Embodiments of the current disclosure relate to the field of encoding and decoding a picture, such as in the field of image or video coding. In particular, embodiments relate to a partitioning tree design and its coding in hybrid video compression, such as in the field of block based image or video coding.

In hybrid video coding, pictures are typically partitioned into smaller variable-sized blocks by which an adaptation to the characteristics of the input video signal can be achieved, which eventually increases the compression efficiency. The partitioning into variable-sized blocks is typically represented by tree structures, such as quadtree, binary tree etc. The associated signaling depends on the chosen tree structure and has an impact on the compression efficiency.

In state-of-the-art hybrid video coding, such as the High-Efficiency Video Coding (HEVC) standard, the input pictures are initially decomposed into disjoint square blocks of a fixed size. Each of these fixed sized square blocks forms the root of a partitioning tree and can be further subdivided into smaller blocks. The blocks that correspond to the leaves of the partitioning tree are used for prediction and transform coding. For these variable-size blocks, the original signal is often predicted; the difference between the original and the prediction signal is referred to as residual signal. The residual signal is transmitted using transform coding. In HEVC, the video pictures are initially partitioned into square blocks, which are referred to as Coding Tree Units (CTUs) and each of the CTUs forms the root of a partitioning tree. HEVC uses quadtree structures for the subdivision into smaller units. At the leaves of the quadtree, the final blocks are referred to as Coding Units (CUs). Each CU forms the root nodes for two further partitioning trees: one for the prediction parameters and another for the transform coding stage. An important property of quadtree structures is that the partitioning syntax element consists of a single bin only. It signals whether or not a current block is split into four equal sized and disjoint blocks; therefore, it is also referred to as a split flag. Figure 1 illustrates the consequence of a single split to the partitioning tree and the result in the two-dimensional picture. The split syntax element is coded in the regular mode of a context-based adaptive entropy coding engine (HEVC uses Context-Based Adaptive Arithmetic Coding, CABAC). Specifically, an adaptive context model is used for coding this syntax element. The context modeling process for the split syntax element of the quadtree employs data on the quadtree depths of the current node

and the already transmitted partitioning trees of neighboring blocks. One out of three available context models is chosen depending on the depths of the neighboring partitioning trees; the following three cases are distinguished: (a) both neighboring depths are greater or equal to the current depth, (b) both neighboring depths are smaller than the current depth, and (c) all other configurations.

In the latest video coding standardization activity of the ITU-T and ISO/IEC, referred to as Versatile Video Coding (WC), non-square block shapes are used. Two alternative partitioning trees have been incorporated into the existing quadtree design: binary and ternary trees. As their name implies, a node can be split into two or three rectangular shapes. Those split shapes are interchangeable, and form a further split tree themselves, a binary-ternary-tree (BTT).

For example, block-based image/video coding and context modelling for content prediction are used for compression of image or video data.

Accordingly, an object of the present disclosure is to provide a concept for encoding and decoding a picture with a high compression efficiency. This object is achieved by the subject matter of the independent claims enclosed herewith.

An aspect of the present disclosure concerns an apparatus for decoding a picture. The apparatus is configured to partition the picture into coding blocks, for example tree leaf blocks, using recursive multi-tree splitting depending on splitting information signaled in a data stream. The apparatus is further configured to decode the picture from coding information which is signaled in the data stream and relates to the coding blocks. The apparatus is configured to partition the picture into the coding blocks depending on splitting information signaled in a data stream, e.g. the data stream, by decoding a split flag of the splitting information from the data stream which indicates whether a predetermined block of the picture is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block becoming one of the coding blocks. That is, for example, if the split flag indicates that the predetermined block is not to be split, the recursive multi-tree splitting is stopped. If the split flag indicates that the predetermined block of the picture is to be split, the partitioning of the picture comprises decoding a quad flag of the splitting information from the data stream which indicates whether the predetermined block of the picture is to be split into four child blocks or not. If the split flag indicates that the predetermined block of the picture is to be split, and if the quad flag indicates that the predetermined block of the picture is not to be split into four child blocks, the partitioning of the picture comprises decoding one or rriore further flags of the splitting information from the data stream which indicate whether the predetermined block of the picture is to be split into two or three child blocks vertically or horizontally. Further, if the split flag indicates that the predetermined block of the picture is to be split, the partitioning of the pic-ture comprises resuming the recursive multi-tree splitting for the child blocks using even further flags of the splitting information. For example, in a further recursion of the recursive multi-tree splitting, one of the child blocks may be the predetermined block. As the apparatus may stop the partitioning, if the split flag indicates that the predetermined block of the picture is to be split, and as the apparatus may decode and/or evaluate the split flag before decoding a further flag, such as the quad flag, the apparatus may only decode one flag, namely the split flag, if the predetermined block is not to be split further. Stopping the recursive partitioning after decoding of only one flag increases the decoding efficiency. Further, if the predetermined block is not to be split further, it may be sufficient to have the split flag in the splitting information, thus decreasing the size of the data stream.

Another aspect concerns an apparatus for decoding a picture. The apparatus is configured to partition the picture into coding blocks using recursive multi-tree splitting depending on splitting information signaled in a data stream. The apparatus is further configured to decode the picture from coding information which is signaled in the data stream and relates to the coding blocks. The apparatus is configured to partition the picture into the coding blocks depending on splitting information signaled in a data stream, e.g. the data stream, by decoding a split flag and a quad flag of the splitting information from the data stream. The split flag indicates whether a predetermined block of the picture is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block becoming one of the coding blocks. The quad flag indicates whether the predeter-mined block of the picture is to be split into four child blocks or not. If the predetermined block of the picture is to be split, but not to be split into four child blocks, the partitioning of the picture comprises obtaining an information about a split direction flag and an information about a triple flag. The apparatus is configured to obtain the information about a split direction flag by decoding a split direction flag from the data stream which indicates whether the predetermined block of the picture is to be split vertically or horizontally, if neither a second nor a third predetermined criterion is fulfilled. If the second predetermined criterion is fulfilled, the apparatus is configured to obtain the information about a split direction flag by inferring that the split direction flag indicates that the predetermined block of the picture is to be split vertically. If the third predetermined criterion is fulfilled, the apparatus is configured to obtain the information about a split direction flag by inferring that the split direction flag indicates that the predetermined block of the picture is to be split horizontally. The apparatus is configured to obtain the information about a split direction flag by decoding a triple flag from the data stream if a fourth predetermined criterion is not fulfilled. The triple flag indicates whether the predetermined block of the picture is to be split into three child blocks or into two child blocks. If the fourth predetermined criterion is fulfilled, the apparatus is configured to obtain the information about a split direction flag by inferring that the triple flag indicates that the predetermined block of the picture is to be split into two child blocks. Further, if the predetermined block of the picture is to be split, the partitioning of the picture comprises resuming the recursive multi-tree splitting for the child blocks using even further flags of the splitting information. The apparatus is further configured to decode the split direction flag from the data stream by context adaptive entropy decoding using a second context. The second context depends on whether, and discriminates between a fulfillment of the following scenarios. In a first scenario, the fourth predetermined criterion would not neither be fulfilled in case of a split direction indicated by the split direction flag being horizontal nor in case of the split direction indicated by the split direction flag being vertical or be fulfilled both in case of a split direction indicated by the split direction flag being horizontal as well as in case of the split direction indicated by the split direction flag being vertical. In a second scenario, the fourth predetermined criterion would be fulfilled in case of the split direction indicated by the split direction flag being horizontal and not be fulfilled in case of the split direction indicated by the split direction flag being vertical. In a third scenario, the fourth predetermined criterion would not be fulfilled in case of the split direction indicated by the split direction flag being horizontal and be fulfilled in case of the split direction indicated by the split direction flag being vertical.

Another aspect concerns an apparatus for decoding a picture, configured to partition the picture into coding blocks using recursive multi-tree splitting depending on splitting information signaled in a data stream. The apparatus is further configured to decode the picture from coding information which is signaled in the data stream and relates to the coding blocks. The apparatus is configured to partition the picture into the coding blocks depending on splitting information signaled in a data stream by decoding a split flag and a quad flag of the splitting information from the data stream. The split flag indicates whether a predetermined block of the picture is to be split or not to be split, the latter implying a stopping of the recursive multi-tree splitting with the predetermined block becoming one of the coding blocks. The quad flag indicates whether the predetermined block of the picture is to be split into four child blocks or not. If the predetermined block of the picture is to be split, but not to be split into four child blocks the apparatus is configured for obtaining an information about a split direction flag and ah information about a triple flag. Obtaining the information about a split direction flag comprises decoding a split direction flag from the data stream which indicates whether the predetermined block of the picture is to be split vertically or horizontally, if neither a second nor a third predetermined criterion is fulfilled. If the second predetermined criterion is fulfilled, obtaining the information about a split direction flag comprises inferring that the split direction flag indicates that the predetermined block of the picture is to be split vertically. If the third predetermined criterion is fulfilled, obtaining the information about a split direction flag comprises inferring that the split direction flag indicates that the predetermined block of the picture is to be split horizontal-ly. Obtaining the information about a triple flag comprises decoding a triple flag from the data stream which indicates whether the predetermined block of the picture is to be split into three child blocks or into two child blocks, if a fourth predetermined criterion is not fulfilled. If the fourth predetermined criterion is fulfilled, obtaining the information about a triple flag comprises inferring that the triple flag indicates that the predetermined block of the picture is to be split into two child blocks. Further, if a fifth predetermined criterion is fulfilled, obtaining the information about a triple flag comprises inferring that the triple flag indicates that the predetermined block of the picture is to be split into three child blocks and suppressing the decoding of the triple flag from the data stream. If the predetermined block of the picture is to be split, the partitioning of the picture comprises resuming the recursive multi-tree splitting for the child blocks using even further flags of the splitting information. Further, the apparatus if configured to decode the split direction flag from the data stream by context adaptive entropy decoding using a second context. The second context depends on whether, and discriminates between, a first number of criteria among the fourth and fifth predetermined criteria being equal, greater and smaller than a second number of criteria among the fourth dnd fifth predetermined criteria. The first number of criteria among the fourth and fifth predetermined criteria would be fulfilled in case of a split direction indicated by the split direction flag being horizontal. The second number of criteria among the fourth and fifth predetermined criteria would be fulfilled in case of the split direction indicated by the split direction flag being vertical.

Another aspect concerns an apparatus for decoding a picture, configured to partition the picture into coding blocks using recursive multi-tree splitting depending on splitting information signaled in a data stream. The apparatus is further configured to decode the picture from coding information which is signaled in the data stream and relates to the coding blocks. The apparatus is configured to. partition the picture into the coding blocks depend-ing on splitting information signaled in a data stream, e.g. the data stream, by decoding a

split flag and a quad flag of the splitting information from the data stream. The split flag indicates whether a predetermined block of the picture is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block becoming one of the coding blocks. The quad flag indicates whether the predetermined block of the picture is to be split into four child blocks or not. If the predetermined block of the picture is to be split, but not to be split into four child blocks, the partitioning of the picture comprises decoding a split direction flag from the data stream and decoding a triple flag from the data stream. The split direction flag indicates whether the predetermined block of the picture is to be split vertically or horizontally. The triple flag indicates whether the predeter-mined block of the picture is to be split into three child blocks or into two child blocks. If the predetermined block of the picture is to be split, the partitioning of the picture comprises resuming the recursive multi-tree splitting for the child blocks using even further flags of the splitting information. The apparatus is further configured to decode the triple flag from the data stream by context adaptive entropy decoding using a third context. The third con-text depends on a number of splits of the recursive multi-tree splitting, e g. a number of recursions of the recursive multi-tree splitting, using which the predetermined block is obtained, or the third context depends on a size of the predetermined block. Alternatively or additionally, the third context depends on whether, and discriminates between the split direction flag indicating a horizontal split direction, and the split direction flag indicating a vertical split direction.

Another aspect concerns an apparatus for decoding a picture, configured to partition the picture into coding blocks using recursive multi-tree splitting depending on splitting information signaled in a data stream. The apparatus if further configured to decode the picture from coding information which is signaled in the data stream and relates to the coding blocks. The apparatus is configured to partition the picture into the coding blocks depending on splitting information signaled in a data stream, e.g. the data stream, by decoding a split flag and a quad flag of the splitting information from the data stream. The split flag indicates whether a predetermined block of the picture is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block becoming one of the coding blocks. The quad flag indicates whether the predetermined block of the picture is to be split into four child blocks or not. If the predetermined block of the picture is to be split, but not to be split into four child blocks, partitioning the picture comprises decoding one or more further flags of the splitting information from the data stream which indicate whether the predetermined block of the picture is to be split into two or three child blocks vertically or horizontally. If the predetermined block of the picture is to be split, par- titioning the picture comprises resuming the recursive multi-tree splitting for the child blocks using even further flags of the splitting information. The apparatus is further configured to select one of a first mode and a second mode. In the first mode, the apparatus is configured to decode the quad flag after the split flag if the split flag indicates that the pre-determined block of the picture is to be split. In the second mode, the apparatus if configured to decode the split flag after the quad flag if the quad flag indicates that the predetermined child block of the picture is not to be split into four child blocks.

Another aspect concerns an apparatus for encoding a picture. The apparatus is configured to partition the picture into coding blocks using recursive multi-tree splitting. The ap-paratus is configured to encode splitting information in a data stream, the splitting information defining the partitioning of the picture. The apparatus is further configured to encode the picture into coding information which relates to the coding blocks and to encode the coding information in the data stream. The apparatus is configured to encode the splitting information in the data stream by encoding a split flag of the splitting information into the data stream. The split flag indicates whether a predetermined block of the picture is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block becoming one of the coding blocks. For example, the split flag may indicate to a decoder decoding the split flag* if the predetermined block is a coding block, e.g. a tree leaf block, or if the predetermined block is further split by another recursion of the recursive multi-tree splitting, thereby instructing the decoder to perform another such recursion. If the split flag indicates that the predetermined block of the picture is to be split, the encoding of the splitting information comprises encoding a quad flag of the splitting information into the data stream. The quad flag indicates whether the predetermined block of the picture is to be split into four child blocks or not. If the split flag indicates that the predetermined block of the picture is to be split, and if the quad flag indicates that the predetermined block of the picture is not to be split into four child blocks, the the encoding of the splitting information further comprises encoding one or more further flags of the splitting information into the data stream. The one or more further flags indicate whether the predetermined block of the picture is to be split into two or three child blocks vertically or horizontally. If the split flag indicates that the predetermined block of the picture is to be split, the encoding of the splitting information further comprises resuming the encoding of the splitting information for the child blocks using even further flags of the splitting information. For example, in a further recursion of the recursive multi-tree splitting, one of the child blocks may be the predetermined block.

Another aspect concerns an apparatus for encoding a picture, configured to partition the picture into coding blocks using recursive multi-tree splitting and to encode splitting information defining the partitioning in a data stream. The apparatus is further configured to encode the picture into coding information which relates to the coding blocks and encode the coding information in the data stream. The apparatus is configured to encode the splitting information in the data stream by encoding a split flag and a quad flag of the splitting information into the data stream. The split flag indicates whether a predetermined block of the picture is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block becoming one of the coding blocks. The quad flag indicates whether the predetermined block of the picture is to be split into four child blocks or not. If the predetermined block of the picture is to be split, but not to be split into four child blocks, and if neither a second nor a third predetermined criterion is fulfilled, the encoding of the splitting information comprises encoding a split direction flag into the data stream. The split direction flag indicates whether the predetermined block of the picture is to be split vertically or horizontally. If the predetermined block of the picture is to be split, but not to be split into four child blocks, and if the second predetermined criterion is fulfilled, the encoding of the splitting information comprises suppressing the encoding of the split direction flag, wherein the split direction flag is to be inferred to indicate that the predetermined block of the picture is to be split vertically, if the second predetermined criterion is fulfilled. If the predetermined block of the picture is to be split, but not to be split into four child blocks, and if the third predetermined criterion is fulfilled, the encoding of the splitting information comprises suppressing the encoding of the split direction flag, wherein same is to be inferred to indicate that the predetermined block of the picture is to be split horizontally, if the third predetermined criterion is fulfilled. If the predetermined block of the picture is to be split, but not to be split into four child blocks, and if a fourth predetermined criterion is not fulfilled, the encoding of the splitting information comprises encoding a triple flag into the data stream. The triple flag indicates whether the predetermined block of the picture is to be split into three child blocks or into two child blocks. If the predetermined block of the picture is to be split, but not to be split into four child blocks, and if the fourth prede-termined criterion is fulfilled, the encoding of the splitting information comprises suppressing the encoding of the triple flag, wherein same is to be inferred to indicate that the predetermined block of the picture is to be split into two child blocks, if the fourth predetermined criterion is fulfilled. If the predetermined block of the picture is to be split, the encoding of the splitting information comprises resuming the encoding of the splitting infor-mation for the child blocks using even further flags of the splitting information. The apparatus is further configured to encode the split direction flag into the data stream by context adaptive entropy encoding using a second context. The second context depends on whether, and discriminates between a fulfillment of the following scenarios. In a first scenario, the fourth predetermined criterion would not neither be fulfilled in case of a split direction indicated by the split direction flag being horizontal nor in case of the split direction indicated by the split direction flag being vertical or be fulfilled both in case of a split direction indicated by the split direction flag being horizontal as well as in case of the split direction indicated by the split direction flag being vertical. In a second scenario, the fourth predetermined criterion would be fulfilled in case of the split direction indicated by the split direction flag being horizontal and not be fulfilled in case of the split direction indicated by the split direction flag being vertical. In a third scenario, the fourth predetermined criterion would not be fulfilled in case of the split direction indicated by the split direction flag being horizontal and be fulfilled in case of the split direction indicated by the split direction flag being vertical.

Another aspect concerns an apparatus for encoding a picture, configured to partition the picture into coding blocks using recursive multi-tree splitting and encode splitting information defining the partitioning in a data stream. The apparatus is further configured to encode the picture into coding information which is signaled in the data stream and relates to the coding blocks and encode the coding information in the data stream. The apparatus is configured to partition the picture into the coding blocks depending on splitting infor-mation signaled in a data stream by encoding a split flag and a quad flag of the splitting information into the data stream. The split flag indicates whether a predetermined block of the picture is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block becoming one of the coding blocks. The quad flag indicates whether the predetermined block of the picture is to be split into four child blocks or not. If the predetermined block of the picture is to be split, but not to be split into four child blocks, and if neither a second nor a third predetermined criterion is fulfilled, the partitioning of the picture comprises encoding a split direction flag into the data stream. The split direction flag indicates whether the predetermined block of the picture is to be split vertically or horizontally. If the predetermined block of the picture is to be split, but not to be split into four child blocks, and if neither a second nor a third predetermined criterion is fulfilled, the partitioning of the picture corhprises suppressing the encoding of the split direction flag wherein same is to be inferred to indicate that predetermined block of the picture is to be split vertically, if the second predetermined criterion is fulfilled. If the predetermined block of the picture is to be split, but not to be split into four child blocks, and if the third predetermined criterion is fulfilled, the partitioning of the picture comprises sup- pressing the encoding of the split direction flag, wherein same is to be inferred to indicate that the predetermined block of the picture is to be split horizontally, if the third predetermined criterion is fulfilled. If the predetermined block of the picture is to be split, but not to be split into four child blocks, and if fourth and fifth predetermined criteria are not fulfilled, the partitioning of the picture comprises encoding a triple flag into the data stream. The triple flag indicates whether the predetermined block of the picture is to be split into three child blocks or into two child blocks. If the predetermined block of the picture is to be split, but not to be split into four child blocks, and if the fourth predetermined criterion is fulfilled, the partitioning of the picture comprises suppressing the encoding the triple flag, wherein same is to be inferred to indicate that the predetermined block of the picture is to be split into two child blocks, if the fourth predetermined criterion is fulfilled. If the predetermined block of the picture is to be split, but not to be split into four child blocks, and if the fifth predetermined criterion is fulfilled, the partitioning of the picture comprises suppressing the encoding of the triple flag, wherein the triple flag is to be inferred to indicate that the predetermined block of the picture is to be split into three child blocks, if the fifth predetermined criterion is fulfilled. If the predetermined block of the picture is to be split, the partitioning of the picture comprises resuming the encoding the splitting information for the child blocks using even further flags of the splitting information. Further, the apparatus is configured to encode the split direction flag into the data stream by context adaptive en-tropy encoding using a second context which depends on whether, and discriminates between a first number being equal, greater or smaller than a second number. The first number is a first number of criteria among the fourth and fifth predetermined criteria which would be fulfilled in case of a split direction indicated by the split direction flag being horizontal. The second number is a second number of criteria among the fourth and fifth pre-determined criteria which would be fulfilled in case of the split direction indicated by the split direction flag being vertical.

Another aspect concerns an apparatus for encoding a picture, configured to partition the picture into coding blocks using recursive multi-tree splitting and encode splitting information defining the partitioning in a data stream. Further, the apparatus is configured to encode the picture into coding information which relates to the coding blocks and encode the coding information in the data stream. The apparatus is configured to encode the splitting information into the data stream by encoding a split flag and a quad flag of the splitting information into the data stream, wherein the split flag indicates whether a predetermined block of the picture is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block becoming one of the coding blocks, and

the quad flag indicates whether the predetermined block of the picture is to be split into four child blocks or not. If the predetermined block of the picture is to be split, but not to be split into four child blocks, the encoding of the splitting information comprises encoding a split direction flag into the data stream and encoding a triple flag into the data stream. The split direction flag indicates whether the predetermined block of the picture is to be split vertically or horizontally. The triple flag indicates whether the predetermined block of the picture is to be split into three child blocks or into two child blocks. If the predetermined block of the picture is to be split, the encoding of the splitting information comprises resuming the encoding of the splitting information for the child blocks using even further flags of the splitting information. The apparatus is configured to encode the triple flag into the data stream by context adaptive entropy encoding using a third context. The third context depends on a number of splits of the recursive multi-tree splitting using which the predetermined block is obtained, or the third context depends on a size of the predetermined block. Additionally or alteratively, the third context depends on whether, and dis-criminates between, the split direction flag indicating a horizontal split direction, and the split direction flag indicating a vertical split direction.

Another aspect concerns an apparatus for encoding a picture, configured to partition the picture into coding blocks using recursive multi-tree splitting and encode splitting information defining the partitioning in a data stream. The apparatus is further configured to encode the picture into coding information which relates to the coding blocks and encode the coding information in the data stream. The apparatus is configured to encode the splitting information into the data stream by encoding a split flag and a quad flag of the splitting information into the data stream, wherein the split flag indicates whether a predetermined block of the picture is to be split qr not to be split thereby stopping the recursive multi-tree splitting with the predetermined block becoming one of the coding blocks, and the quad flag indicates whether the predetermined block of the picture is to be split into four child blocks or not. If the predetermined block of the picture is to be split, but not to be split into four child blocks, the encoding of , the splitting information comprises encoding one or more further flags of the splitting information into the data stream which indicate whether the predetermined block of the -picture is to be split into two or three child blocks vertically or horizontally. If the predetermined block of the picture is to be split, the encoding of the splitting information comprises resuming the encoding of the splitting information for the child blocks using even further flags of the splitting information. The apparatus is configured to select one of a first mode and a second mode. In the first mode, the appa-ratus is configured to encode the quad flag after the split flag if the split flag indicates that the predetermined block of the picture is to be split. In the second mode, the apparatus is configured to encode the split flag after the quad flag if the quad flag indicates that the predetermined child block of the picture is not to be split into four child blocks.

Another aspect concerns a method for decoding a picture, comprising a partitioning of the picture 12’ into coding blocks using recursive multi-tree splitting depending on splitting information signaled in a data stream, and further comprising a decoding the picture 12’ from coding information which is signaled in the data stream and relates to the coding blocks. The method further comprises partitioning the picture 12’ into the coding blocks depending on splitting information signaled in a data stream by decoding a split flag of the splitting information from the data stream which indicates whether a predetermined block of the picture 12' is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block becoming one of the coding blocks. If the split flag indicates that the predetermined block of the picture 12' is to be split, the partitioning of the picture comprises decoding a quad flag of the splitting information from the data stream which indicates whether the predetermined block of the picture 12' is to be split into four child blocks or not. Ilf the quad flag indicates that the predetermined block of the picture 12’ is not to be split into four child blocks, the partitioning of the picture comprises decoding one or more further flags of the splitting information from the data stream which indicate whether the predetermined block of the picture 12’ is to be split into two or three child blocks vertically or horizontally. If the split flag indicates that the predetermined block of the picture 12’ is to be split, the partitioning of the picture comprises resuming the recursive multi-tree splitting for the child blocks using even further flags of the splitting information.

Another aspect concerns a method for decoding a picture, comprising a partitioning of the picture 12’ into coding blocks using recursive multi-tree splitting depending on splitting information signaled in a data stream. The method further comprises decoding the picture 12' from coding information which is signaled in the data stream and relates to the coding blocks. The method comprises partitioning the picture 12’ into the coding blocks depending on splitting information signaled in a data stream by decoding a split flag and a quad flag of the splitting information from the data stream, wherein the split flag indicates whether a predetermined block of the picture 12’ is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block becoming one of the coding blocks, and the quad flag indicates whether the predetermined block of the picture 12’ is to be split into four child blocks or not. If the predetermined block of the pic-ture 12’ is to be split, but not to be split into four child blocks, the partitioning of the picture comprises decoding a split direction flag from the data stream which indicates whether the predetermined block of the picture 12’ is to be split vertically or horizontally, if neither a second nor a third predetermined criterion is fulfilled. If the predetermined block of the picture 12' is to be split, but not to be split into four child blocks, the partitioning of the pic-ture comprises inferring that the split direction flag indicates that the predetermined block of the picture 12’ is to be split vertically, if the second predetermined criterion is fulfilled. If the predetermined block of the picture 12' is to be split, but not to be split into four child blocks, the partitioning of the picture comprises inferring that the split direction flag indicates that the predetermined block of the picture 12’ is to be split horizontally, if the third predetermined criterion is fulfilled. If the predetermined block of the picture 12’ is to be split, but not to be split into four child blocks, the partitioning of the picture comprises decoding a triple flag from the data stream which indicates whether the predetermined block of the picture 12’ is to be split into three child blocks or into two child blocks, if a fourth predetermined criterion is not fulfilled. If the predetermined block of the picture 12’ is to be split, but not to be split into four child blocks, the partitioning of the picture comprises inferring that the triple flag indicates that the predetermined block of the picture 12’ is to be split into two child blocks, if the fourth predetermined criterion is fulfilled. If the predetermined block of the picture 12' is to be split, the partitioning of the picture comprises resuming the recursive multi-tree splitting for the child blocks using even further flags of the splitting information. The method further comprises decoding the split direction flag from the data stream by context adaptive entropy decoding using a second context which depends on whether, and discriminates between, a and which of the following scenarios being fulfilled: (i) the fourth predetermined criterion would not neither be fulfilled in case of a split direction indicated by the split direction flag being horizontal nor in case of the split direction indicated by the split direction flag being vertical or be fulfilled both in case of a split direction indicated by the split direction flag being horizontal as well as in case of the split direction indicated by the split direction flag being vertical, (ii) the fourth predetermined criterion would be fulfilled in case of the split direction indicated by the split direction flag being horizontal and not be fulfilled in case of the split direction indicated by the split direction flag being vertical, and (iii) the fourth predetermined criterion would not be fulfilled in case of the split direction indicated by the split direction flag being horizontal and be fulfilled in case of the split direction indicated by the split direction flag being verti-cal.

Another aspect concerns a method for decoding a picture, comprising a partitioning of the picture 12’ into coding blocks using recursive multi-tree splitting depending on splitting

information signaled in a data stream, and further comprising decoding the picture 12’ from coding information which is signaled in the data stream and relates to the coding blocks. The method comprises partitioning the picture 12’ into the coding blocks depending on splitting information signaled in a data stream by decoding a split flag and a quad flag of the splitting information from the data stream, wherein the split flag indicates whether a predetermined block of the picture 12’ is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block becoming one of the coding blocks, and the quad flag indicates whether the predetermined block of the picture 12' is to be split into four child blocks or not. If the predetermined block of the pic-ture 12' is to be split, but not to be split into four child blocks, the partitioning of the picture comprises decoding a split direction flag from the data stream which indicates whether the predetermined block of the picture 12’ is to be split vertically or horizontally, if neither a second nor a third predetermined criterion is fulfilled. If the predetermined block of the picture 12’ is to be split, but not to be split into four child blocks, the partitioning of the pic-ture further comprises inferring that the split direction flag indicates that the predetermined block of the picture 12’ is to be split vertically, if the second predetermined criterion is fulfilled. If the predetermined block of the picture 12’ is to be split, but not to be split into four child blocks, the partitioning of the picture further comprises inferring that the split direction flag indicates that the predetermined block of the picture 12’ is to be split horizontally, if the third predetermined criterion is fulfilled. If the predetermined block of the picture 12’ is to be split, but not to be split into four child blocks, the partitioning of the picture further comprises decoding a triple flag from the data stream which indicates whether the predetermined block of the picture 12’ is to be split into three child blocks or into two child blocks, if a fourth predetermined criterion is not fulfilled. If the predetermined block of the picture 12' is to be split, but not to be split into four child blocks, the partitioning of the picture further comprises inferring that the triple flag indicates that the predetermined block of the picture 12’ is to be split into two child blocks, if the fourth predetermined criterion is fulfilled, and that the triple flag indicates that the predetermined block of the picture 12' is to be split into three child blocks and suppress the decoding of the triple flag from the data stream, if a fifth predetermined criterion is fulfilled. If the predetermined block of the picture 12’ is to be split, the partitioning of the picture comprises resuming the recursive multi-tree splitting for the child blocks using even further flags of the splitting information. Further, the method comprises decoding the split direction flag from the data stream by context adaptive entropy decoding using a second context which depends on whether, and discriminates between (i) a first number of criteria among the fourth and fifth predetermined criteria which would be fulfilled in case of a split direction indicated by the split di- rection flag being horizontal equals a second number of criteria among the fourth and fifth predetermined criteria which would be fulfilled in case of the split direction indicated by the split direction flag being vertical (ii) the first number being greater than the second number, and (iii) the first number being smaller than the second number.

CLAIMS

1. Apparatus (400) for decoding a picture (12’), configured to

partition the picture (12’) into coding blocks (425) using recursive multi-tree splitting de-pending on splitting information (415) signaled in a data stream (14),

decode the picture (12’) from coding information (440) which is signaled in the data stream (14) and relates to the coding blocks (425),

wherein the apparatus (400) is configured to partition the picture (12’) into the coding blocks (425) depending on splitting information (415) signaled in a data stream (14) by

decoding a split flag (416) of the splitting information (415) from the data stream (14) which indicates whether a predetermined block (411) of the picture (12') is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block (411) becoming one of the coding blocks (425),

if the split flag (416) indicates that the predetermined block (411) of the picture (12’) is to be split,

decoding a quad flag (417) of the splitting information (415) from the data stream (14) which indicates whether the predetermined block (41 1) of the picture (12’) is to be split into four child blocks (412) or not,

if the quad flag (417) indicates that the predetermined block (411) of the picture (12’) is not to be split into four child blocks (412),

decoding one or more further flags (418) of the splitting information (415) from the data stream (14) which indicate whether the predetermined block (41 1) of the picture (12’) is to be split into two or three child blocks (412) vertically or horizontally,

resuming the recursive multi-tree splitting for the child blocks (412) using even further flags of the splitting information (415).

2. Apparatus (400) of claim 1 , configured to

resume the recursive multi-tree splitting for the child blocks (412) using even further flags of the splitting information (415) by, for a predetermined child block of the child blocks (412),

decoding a further split flag (416) of the splitting information (415) from the data stream (14) which indicates whether the predetermined child block of the picture (12’) is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined child block becoming a coding block,

if the further split flag (416) indicates that the predetermined child block of the picture (12’) is to be split,

decoding a further quad flag (417) of the splitting information (415) from the data stream (14) which indicates whether the predetermined child block of the picture (12’) is to be split into four child blocks (412) or not,

if the further quad flag (417) indicates that the predetermined child block of the picture (12’) is not to be split into four child blocks (412),

decoding one or more further flags (418) of the splitting information (415) from the data stream (14) which indicate whether the predetermined child block of the picture (12') is to be split into two or three child blocks (412) vertically or horizontally,

resuming the recursive multi-tree splitting for the child blocks (412) of the predetermined child block using even further flags of the splitting information (415).

3. Apparatus (400) of claim 1 or 2, configured to

Infer, depending on one or more criteria being fulfilled or not, that one or more flags of the splitting information (415) assume a predetermined flag state with not decoding the one or more flags of the splitting information (415) from the data stream (14).

4, Apparatus (400) of claim 3, wherein the one or more criteria relate to one or more of

child block area, child block width, child block height, a current split depth and a split line alignment with a picture border.

5. Apparatus (400) of any of the previous claims, configured to

start the recursive multi-tree splitting at each tree-root block of tree-root blocks into which the picture (12’) is subdivided in rows and columns.

6. Apparatus (400) of any of the previous claims, configured to

start the recursive multi-tree splitting at tree-root blocks into which the picture (12') is subdivided in rows and columns.

7. Apparatus (400) of any of the previous claims, configured to

Infer that the quad flag (417) indicates that the predetermined block (41 1) of the picture (12’) is not to be split into four child blocks (412) and suppress the decoding of the quad flag (417) from the data stream (14), if a first predetermined criterion is fulfilled.

8. Apparatus (400) of any of the previous claims, configured so that the first predetermined criterion is fulfilled if the predetermined block (411) results from a non-quad split of a parent block.

9. Apparatus (400) of any of the previous claims, configured to, in the decoding of one or more further flags (418) of the splitting information (415) from the data stream (14) which indicate whether the predetermined child block of the picture (12’) is to be split into two or three child blocks (412) vertically or horizontally,

decode a split direction flag (518) from the data stream (14) which indicates whether the predetermined block (411) of the picture (12') is to be split vertically or horizontally, and

decode a triple flag (519) from the data stream (14) which indicates whether the predetermined block (411) of the picture (12') is to be split into three child blocks (412) or into two child blocks (412).

10. Apparatus (400) of claim 9, configured to

infer that the split direction flag (518) indicates that the predetermined block (411) of the picture (12’) is to be split vertically and suppress the decoding of the split direction flag (518) from the data stream (14), if a second predetermined criterion is fulfilled, and infer that the split direction flag (518) indicates that the predetermined block (411) of the picture (12’) is to be split horizontally and suppress the decoding of the split direction flag (518) from the data stream (14), if a third predetermined criterion is fulfilled.

11. Apparatus (400) of claim 10, wherein

the second predetermined criterion is fulfilled is halving the predetermined block (411) horizontally would yield a width falling below a predetermined minimum dimension, and

the third predetermined criterion is fulfilled if halving the predetermined block (411) vertically would yield a height falling below the predetermined minimum dimension.

12. Apparatus (400) of any of claims 9 to 11 , configured to

infer that the triple flag (519) indicates that the predetermined block (411) of the picture (12’) is to be split into two child blocks (412) and suppress the decoding of the triple flag (519) from the data stream (14), if a fourth predetermined criterion is fulfilled.

13. Apparatus (400) of any of claims 9 to 11 , configured to

Infer that the triple flag (519) indicates that the predetermined block (411) of the picture (12’) is to be split into two child blocks (412) and suppress the decoding of the triple flag (519) from the data stream (14), if a fourth predetermined criterion is fulfilled, and

infer that the triple flag (519) indicates that the predetermined block (411) of the picture (12’) is to be split into three child blocks (412) and suppress the decoding of the triple flag (519) from the data stream (14), if a fifth predetermined criterion is fulfilled.

14. Apparatus (400) of any of claims 12 and 13, wherein

the fourth predetermined criterion is fulfilled if trisecting the predetermined block (411 ) in a split direction indicated by the direction flag would yield a dimension of the predetermined block (411) along the split direction which split falls below a predetermined minimum dimension.

15. Apparatus (400) of any of claims 12 to 14, wherein

the fifth predetermined criterion is fulfilled if halving the predetermined block (411) in a split direction indicated by the direction flag would yield a dimension of the predetermined block (41 1) along the split direction which exceeds a predetermined maximum dimension.

16. Apparatus (400) of any of the previous claims, configured to

resume the recursive multi-tree splitting for the child blocks (412) using even further flags of the splitting information (415) by, for a predetermined child block of the child blocks (412),

decoding a further quad flag (417) of the splitting information (415) from the data stream (14) which indicates whether the predetermined child block of the picture (12’) is to be split into four child blocks (412) or not,

if the further quad flag (417) indicates that the predetermined child block of the picture (12’) is not to be split into four child blocks (412),

decoding a further split flag (416) of the splitting information (415) from the data stream (14) which indicates whether the predetermined child block of the picture (12’) is to be split, or not to be split thereby stopping the recursive multi-tree splitting with the predetermined child block becoming a coding block,

if the further split flag (416) indicates that the predetermined child block of the picture (12') is to be split,

decoding one or more further flags (418) of the splitting information (415) from the data stream (14) which indicate whether the predetermined child block of the picture (12’) is to be split into two or three child blocks (412) vertically or horizontally,

resuming the recursive multi-tree splitting for the child blocks (412) of the predetermined child block using even even further flags of the splitting information (415).

17. Apparatus (400) of any of the previous claims, configured to

infer that the quad flag (417) indicates that the predetermined block (411) of the picture (12’) is not to be split into four child blocks (412) and suppress the decoding of the quad flag (417) from the data stream (14), if a first predetermined criterion is fulfilled, and decode the split flag (416) of the splitting information (415) from the data stream (14) by context adaptive entropy decoding using a first context which depends on

whether the first predetermined criterion is fulfilled.

18. Apparatus (400) of claim 17, wherein the first context additionally depends on

a number of splits of the recursive multi-tree splitting using which the predetermined block (411) is obtained, or

a size of the predetermined block (411).

19. Apparatus (400) of claim 17, wherein the first context additionally depends on, and discriminates between,

a number of splits of the recursive multi-tree splitting using which the predetermined block (411) is obtained, is below a predetermined threshold number of splits, or

a size of the predetermined block (411) is above a predetermined threshold size.

20. Apparatus (400) of any of claims 17 to 19, wherein the first context additionally depends on

A width of a coding block above the predetermined block (41 1), and

A height of a coding block to the left of the predetermined block (411).

21. Apparatus (400) of any of claims 17 to 19, wherein the first context additionally depends on whether, and discriminates between,

a width of a coding block above the predetermined block (411) is smaller than a width of the predetermined block (41 1) and a height of a coding block to the left of the predetermined block (41 1) is smaller than a height of the predetermined block (41 1),

the width of the coding block above the predetermined block (411) is smaller than the width of the predetermined block (41 1 ) and the height of the coding block to the left of the predetermined block (411) is larger than the height of the predetermined block (411), and

the width of the coding block above the predetermined block (41 1) is smaller than the width of the predetermined block (411) and the height of the coding block to the left of the predetermined block (41 1) is larger than the height of the predetermined block (411) or the width of the coding block above the predetermined block (411) is larger than the width of the predetermined block (41 1) and the height of the coding block to the left of the predetermined block (41 1) is smaller than the height of the predetermined block (411).

22. Apparatus (400) of any of the previous claims, configured to

perform the splitting into four child blocks (412) so that the four child blocks (412) are equally sized and arranged in a (2x2) array, and

perform the recursive multi-tree splitting using a depth first traversal order and traverse child blocks resulting from splitting one parent block from left to right in case of a horizontal split, from top to bottom in case of a vertical split and in a rowwise raster scan order from top left to bottom right in case of a splitting into four child blocks (412).

23. Apparatus (400) of any of the previous claims, configured to

in the decoding of one or more further flags (418) of the splitting information (415) from the data stream (14) which indicate whether the predetermined child block of the picture (12') is to be split into two or three child blocks (412) vertically or horizontally

decode a split direction flag (518) from the data stream (14) which indicates whether the predetermined block (411) of the picture (12’) is to be split vertically or horizontally, and

decode a triple flag (519) from the data stream (14) which indicates whether the predetermined block (411) of the picture (12’) is to be split into three child blocks (412) or into two child blocks (412),

infer that the quad flag (417) indicates that the predetermined block (411) of the picture (12’) is not to be split into four child blocks (412) and suppress the decoding of the quad flag (417) from the data stream (14), if a first predetermined criterion is fulfilled,

infer that the split direction flag (518) indicates that the predetermined block (411 ) of the picture (12') is to be split vertically and suppress the decoding of the split direction flag (518) from the data stream (14), if a second predetermined criterion is fulfilled, and infer that the split direction flag (518) indicates that the predetermined block (411) of the picture (12’) is to be split horizontally and suppress the decoding of the split direction flag (518) from the data stream (14), if a third predetermined criterion is fulfilled, and

infer that the triple flag (519) indicates that the predetermined block (411) of the picture (12’) is to be split into two child blocks (412) and suppress the decoding of the triple flag (519) from the data stream (14), if a fourth predetermined criterion is fulfilled,

decode the split flag (416) of the splitting information (415) from the data stream (14) by context adaptive entropy decoding using a first context which depends on

a sum of addends each of which is associated with, and assumes a non-zero value if, while being zero otherwise,

the first predetermined criterion is not fulfilled,

the second predetermined criterion is not fulfilled,

the third predetermined criterion is not fulfilled,

the second predetermined criterion is not fulfilled and the fourth predetermined criterion would not be fulfilled in case of a split direction indicated by the split direction flag (518) being horizontal, and

the third predetermined criterion is not fulfilled and the fourth predetermined criterion would not be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical, respectively.

24. Apparatus (400) of any of the previous claims, configured to

in the decoding of one or more further flags (418) of the splitting information (415) from the data stream (14) which indicate whether the predetermined child block of the picture (12’) is to be split into two or three child blocks (412) vertically or horizontally

decode a split direction flag (518) from the data stream (14) which indicates whether the predetermined block (411) of the picture (12’) is to be split vertically or horizontally, and

decode a triple flag (519) from the data stream (14) which indicates whether the predetermined block (411) of the picture (12’) is to be split into three child blocks (412) or into two child blocks (412),

infer that the quad flag (417) indicates that the predetermined block (411) of the picture (12’) is not to be split into four child blocks (412) and suppress the decoding of the quad flag (417) from the data stream (14), if a first predetermined criterion is fulfilled,

infer that the split direction flag (518) indicates that the predetermined block (411) of the picture (12’) is to be split vertically and suppress the decoding of the split direction flag (518) from the data stream (14), if a second predetermined criterion is fulfilled, and infer that the split direction flag (518) indicates that the predetermined block (411) of the picture (12') is to be split horizontally and suppress the decoding of the split direction flag (518) from the data stream (14), if a third predetermined criterion is fulfilled, and

infer that the triple flag (519) indicates that the predetermined block (411) of the picture (12') is to be split into two child blocks (412) and suppress the decoding of the triple flag (519) from the data stream (14), if a fourth predetermined criterion is fulfilled, and infer that the triple flag (519) indicates that the predetermined block (411) of the picture (12’) is to be split into three child blocks (412) and suppress the decoding of the triple flag (519) from the data stream (14), if a fifth predetermined criterion is fulfilled,

decode the split flag (416) of the splitting information (415) from the data stream (14) by context adaptive entropy decoding using a first context which depends on

a sum of addends each of which is associated with, and assumes a non-zero value if, while being zero otherwise,

the first predetermined criterion is not fulfilled,

the second predetermined criterion is not fulfilled, and the fifth predetermined criterion would not be fulfilled in case of the split direction indicated by the split direction flag (518) being horizontal,

the third predetermined criterion is not fulfilled, and the fifth predetermined criterion would not be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical,

the second predetermined criterion is not fulfilled and the fourth predetermined criterion would not be fulfilled in case of the split direction indicated by the split direction flag (518) being horizontal, and

the third predetermined criterion is not fulfilled and the fourth predetermined criterion would not be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical, respectively.

25. Apparatus (400) of one of claims 23 and 24, wherein the first context additionally depends on whether, and discriminates between,

a third of the sum of addends plus one is zero, one and two, wherein the non-zero value of the addend associated with the first predetermined criterion being not fulfilled is two, and the non-zero values of the other addends are one.

26. Apparatus (400) of any of claims 23 to 25, wherein the first context additionally depends on

a width of a coding block above the predetermined block (411), and

a height of a coding block to the left of the predetermined block (411).

27. Apparatus (400) of any of claims 23 to 25, wherein the first context additionally depends on whether, and discriminates between,

a width of a coding block above the predetermined block (411) is smaller than a width of the predetermined block (411) and a height of a coding block to the left of the predetermined block (411) is smaller than a height of the predetermined block (411),

the width of the coding block above the predetermined block (411) is smaller than the width of the predetermined block (411) and the height of the coding block to the left of the predetermined block (411) is larger than the height of the predetermined block (411), and

the width of the coding block above the predetermined block (411) is smaller than the width of the predetermined block (411) and the height of the coding block to the left of the predetermined block (411) is larger than the height of the predetermined block (411) or the width of the coding block above the predetermined block (411 ) is larger than the width of the predetermined block (411) and the height of the coding block to the left of the predetermined block (41 1) is smaller than the height of the predetermined block (41 1).

28. Apparatus (400) of any of the previous claims, configured to, in the decoding of one or more further flags (418) of the splitting information (415) from the data stream (14) which indicate whether the predetermined child block of the picture (12') is to be split into two or three child blocks (412) vertically or horizontally

decode a split direction flag (518) from the data stream (14) which indicates whether the predetermined block (41 1) of the picture (12’) is to be split vertically or horizontally, if neither a second nor a third predetermined criterion is fulfilled,

infer that the split direction flag (518) indicates that the predetermined block (411) of the picture (12') is to be split vertically, if the second predetermined criterion is fulfilled, and

infer that the split direction flag (518) indicates that the predetermined block (411) of the picture (12’) is to be split horizontally, if the third predetermined criterion is fulfilled,

decode a triple flag (519) from the data stream (14) which indicates whether the predetermined block (411) of the picture (12’) is to be split into three child blocks (412) or into two child blocks (412), if a fourth predetermined criterion is not fulfilled, and

infer that the triple flag (519) indicates that the predetermined block (411) of the picture (12') is to be split into two child blocks (412), if the fourth predetermined criterion is fulfilled,

decode the split direction flag (518) from the data stream (14) by context adaptive entropy decoding using a second context (552) which depends on whether, and discriminates between,

the fourth predetermined criterion would not neither be fulfilled in case of a split direction indicated by the split direction flag (518) being horizontal nor in case of the split direction indicated by the split direction flag (518) being vertical or be fulfilled both in case of a split direction indicated by the split direction flag (518) being horizontal as well as in case of the split direction indicated by the split direction flag (518) being vertical,

the fourth predetermined criterion would be fulfilled in case of the split direction indicated by the split direction flag (518) being horizontal and not be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical, and

the fourth predetermined criterion would not be fulfilled in case of the split direction indicated by the split direction flag (518) being horizontal and be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical.

29. Apparatus (400) of any of the previous claims, configured to, in the decoding of one or more further flags (418) of the splitting information (415) from the data stream (14) which indicate whether the predetermined child block of the picture (12’) is to be split into two or three child blocks (412) vertically or horizontally

decode a split direction flag (518) from the data stream (14) which indicates whether the predetermined block (411) of the picture (12') is to be split vertically or horizontally, if neither a second nor a third predetermined criterion is fulfilled,

infer that the split direction flag (518) indicates that the predetermined block (411) of the picture (12’) is to be split vertically, if the second predetermined criterion is fulfilled, and

infer that the split direction flag (518) indicates that the predetermined block (411) of the picture (12’) is to be split horizontally, if the third predetermined criterion is fulfilled,

decode a triple flag (519) from the data stream (14) which indicates whether the predetermined block (411) of the picture (12’) is to be split into three child blocks (412) or into two child blocks (412), if fourth and fifth predetermined criteria are not fulfilled, and

infer that the triple flag (519) indicates that the predetermined block (411) of the picture (12’) is to be split into two child blocks (412), if the fourth predetermined criterion is fulfilled, and infer that the triple flag (519) indicates that the predetermined block (411) of the picture (12’) is to be split into three child blocks (412) and suppress the decoding of the triple flag (519) from the data stream (14), if the fifth predetermined criterion is fulfilled,

decode the split direction flag (518) from the data stream (14) by context adaptive entropy decoding using a second context (552) which depends on whether, and discriminates between,

a first number of criteria among the fourth and fifth predetermined criteria which would be fulfilled in case of a split direction indicated by the split direction flag (518) being horizontal equals a second number of criteria among the fourth and fifth predetermined criteria which would be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical,

the first number being greater than the second number, and

the first number being smaller than the second number.

30. Apparatus (500) for decoding a picture (12’), configured to

partition the picture (12’) into coding blocks (425) using recursive multi-tree splitting depending on splitting information (415) signaled in a data stream (14) I

decode the picture (12’) from coding information (440) which is signaled in the data stream (14) and relates to the coding blocks (425),

wherein the apparatus (500) is configured to partition the picture (12’) into the coding blocks (425) depending on splitting information (415) signaled in a data stream (14) by

decoding a split flag (416) and a quad flag (417) of the splitting information (415) from the data stream (14), wherein the split flag (416) indicates whether a prede-

termined block (411) of the picture (12’) is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block (411) becoming one of the coding blocks (425), and the quad flag (417) indicates whether the predetermined block (411) of the picture (12') is to be split into four child blocks (412) or not,

if the predetermined block (411) of the picture (12‘) is to be split, but not to be split into four child blocks (412),

decoding a split direction flag (518) from the data stream (14) which indicates whether the predetermined block (411) of the picture (12’) is to be split vertically or horizontally, if neither a second nor a third predetermined criterion is fulfilled,

inferring that the split direction flag (518) indicates that the predetermined block (411) of the picture (12’) is to be split vertically, if the second predetermined criterion is fulfilled, and

inferring that the split direction flag (518) indicates that the predetermined block (411) of the picture (12’) is to be split horizontally, if the third predetermined criterion is fulfilled,

decoding a triple flag (519) from the data stream (14) which indicates whether the predetermined block (411) of the picture (12’) is to be split into three child blocks (412) or into two child blocks (412), if a fourth predetermined criterion is not fulfilled, and

inferring that the triple flag (519) indicates that the predetermined block (41 1) of the picture (12’) is to be split into two child blocks (412), if the fourth predetermined criterion is fulfilled,

if the predetermined block (411) of the picture (12’) is to be split,

resuming the recursive multi-tree splitting for the child blocks (412) using even further flags of the splitting information (415),

decode the split direction flag (518) from the data stream (14) by context adaptive entropy decoding using a second context (552) which depends on whether, and discriminates be-tween,

the fourth predetermined criterion would not neither be fulfilled in case of a split direction indicated by the split direction flag (518) being horizontal nor in case of the split direction indicated by the split direction flag (518) being vertical or be fulfilled both in case of a split direction indicated by the split direction flag (518) being horizontal as well as in case of the split direction indicated by the split direction flag (518) being vertical,

the fourth predetermined criterion would be fulfilled in case of the split direction indicated by the split direction flag (518) being horizontal and not be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical, and

the fourth predetermined criterion would not be fulfilled in case of the split direction indicated by the split direction flag (518) being horizontal and be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical.

31. Apparatus (600) for decoding a picture (12’), configured to

partition the picture (12') into coding blocks (425) using recursive multi-tree splitting depending on splitting information (415) signaled in a data stream (14),

decode the picture (12’) from coding information (440) which is signaled in the data stream (14) and relates to the coding blocks (425),

wherein the apparatus (600) is configured to partition the picture (12’) into the coding blocks (425) depending on splitting information (415) signaled in a data stream (14) by

decoding a split flag (416) and a quad flag (417) of the splitting information (415) from the data stream (14), wherein the split flag (416) indicates whether a predetermined block (411) of the picture (12’) is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block (411) becoming one of the coding blocks (425), and the quad flag (417) indicates whether the predetermined block (41 1) of the picture (12’) is to be split into four child blocks (412) or not,

if the predetermined block (411) of the picture (12’) is to be split, but not to be split into four child blocks (412),

decoding a split direction flag (518) from the data stream (14) which indicates whether the predetermined block (411) of the picture (12’) is to be split vertically or horizontally, if neither a second nor a third predetermined criterion is fulfilled,

inferring that the split direction flag (518) indicates that the predetermined block (411) of the picture (12') is to be split vertically, if the second predetermined criterion is fulfilled, and

inferring that the split direction flag (518) indicates that the predetermined block (41 1) of the picture (12’) is to be split horizontally, if the third predetermined criterion is fulfilled,

decoding a triple flag (519) from the data stream (14) which indicates whether the predetermined block (411) of the picture (12’) is to be split into three child blocks (412) or into two child blocks (412), if a fourth predetermined criterion is not fulfilled, and

inferring that the triple flag (519) indicates that the predetermined block (411) of the picture (12’) is to be split into two child blocks (412), if the fourth predetermined criterion is fulfilled, and that the triple flag (519) indicates that the predetermined block (411) of the picture (12’) is to be split into three child blocks (412) and suppress the decoding of the triple flag (519) from the data stream (14), if a fifth predetermined criterion is fulfilled,

if the predetermined block (41 1) of the picture (12’) is to be split,

resuming the recursive multi-tree splitting for the child blocks (412) using even further flags of the splitting information (415),

decode the split direction flag (518) from the data stream (14) by context adaptive entropy decoding using a second context (552) which depends on whether, and discriminates between,

a first number of criteria among the fourth and fifth predetermined criteria which would be fulfilled in case of a split direction indicated by the split direction flag (518) being horizontal equals a second number of criteria among the fourth and fifth predetermined criteria which would be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical,

the first number being greater than the second number, and

the first number being smaller than the second number.

32. Apparatus (400;500;600) of claim 28 or 30 or 31 , wherein the second context (552) additionally depends on whether, and discriminates between,

a width of the predetermined block (411) equaling a height of the current block, and

the width of the predetermined block (411 ) being larger than the height of the current block, and

the width of the predetermined block (41 1) being smaller than the height of the current block.

33. Apparatus (400;500;600) of claim 28 or any of the claims 30 to 32, wherein the second context (552),

if the fourth predetermined criterion would not neither be fulfilled in case of a split direction indicated by the split direction flag (518) being horizontal nor in case of the split direction indicated by the split direction flag (518) being vertical or be fulfilled both in case of a split direction indicated by the split direction flag (518) being horizontal as well as in case of the split direction indicated by the split direction flag (518) being vertical, additionally depends on whether, and discriminates between,

a width of the predetermined block (411) equaling a height of the current block, and

the width of the predetermined block (411) being larger than the height of the current block, and

the width of the predetermined block (41 1) being smaller than the height of the current block, and

if the fourth predetermined criterion would be fulfilled in either one of the case of the split direction indicated by the split direction flag (518) being horizontal and the case of the split direction indicated by the split direction flag (518) being vertical, Is non-discriminative between,

the width of the predetermined block (411) equaling the height of the current block, and

the width of the predetermined block (411) being larger than the height of the current block, and

the width of the predetermined block (411) being smaller than the height of the current block.

34. Apparatus (400;500;600) of claim 28 or 30, wherein the second context (552) additionally depends on whether, and discriminates between,

a first ratio between a width of the predetermined block (411) and a width of a coding block above the predetermined block (411) equaling a second ratio between a height of the current block and a height of a coding block to the left of the predetermined block (411), and

the first ratio being larger than the second ratio, and

the first ratio being smaller than the second ratio.

35. Apparatus (400;500;600) of claim 28 or any of the claims 30 to 34, wherein the second context (552),

if the fourth predetermined criterion would not neither be fulfilled in case of a split direction indicated by the split direction flag (518) being horizontal nor in case of the split direction indicated by the split direction flag (518) being vertical or be fulfilled both in case of a split direction indicated by the split direction flag (518) being horizontal as well as in case of the split direction indicated by the split direction flag (518) being vertical, additionally depends on whether, and discriminates between,

a first ratio between a width of the predetermined block (411) and a width of a coding block above the predetermined block (411) equaling a second ratio between a height of the current block and a height of a coding block to the left of the predetermined block (411), and

the first ratio being larger than the second ratio, and

the first ratio being smaller than the second ratio,

if the fourth predetermined criterion would be fulfilled in either one of the case of the split direction indicated by the split direction flag (518) being horizontal and the case of the split direction indicated by the split direction flag (518) being vertical, is non-discriminative between,

a first ratio between a width of the predetermined block (411) and a width of a coding block above the predetermined block (411 ) equaling a second ratio between a height of the current block and a height of a coding block to the left of the predetermined block (411), and

the first ratio being larger than the second ratio, and

the first ratio being smaller than the second ratio.

36. Apparatus (400;500;600) of claim 28 or any of the claims 30 to 35, wherein the second context (552) is non-discriminative between,

whether the fourth predetermined criterion would neither be fulfilled In case of the split direction indicated by the split direction flag (518) being horizontal nor in case of the split direction indicated by the split direction flag (518) being vertical and

whether the fourth predetermined criterion would be fulfilled both in case of a split direction indicated by the split direction flag (518) being horizontal as well as in case of the split direction indicated by the split direction flag (518) being vertical.

37. Apparatus (400;500;600) of claim 28 or any of the claims 30 to 36, configured to

decode the triple flag (519) from the data stream (14) by context adaptive entropy decoding using a third context (853) which depends on,

a number of splits of the recursive multi-tree splitting using which the predetermined block (411) is obtained, or

a size of the predetermined block (41 1).

38. Apparatus (400;500;600) of claim 28 or any of the claims 30 to 37, configured to

decode the triple flag (519) from the data stream (14) by context adaptive entropy decoding using a third context (853) which depends on whether, and discriminates between,

the split direction flag (518) indicating a horizontal split direction, and

the split direction flag (518) indicating a vertical split direction.

39. Apparatus (800) for decoding a picture (12’), configured to

partition the picture (12’) into coding blocks (425) using recursive multi-tree splitting depending on splitting information (415) signaled in a data stream (14),

decode the picture (12’) from coding information (440) which is signaled in the data stream (14) and relates to the coding blocks (425),

wherein the apparatus (800) is configured to partition the picture (12’) into the coding blocks (425) depending on splitting informatiori (415) signaled in a data stream (14) by

decoding a split flag (416) and a quad flag (417) of the splitting information (415) from the data stream (14), wherein the split flag (416) indicates whether a predetermined block (411) of the picture (12‘) is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block (411) becoming one of the coding blocks (425), and the quad flag (417) indicates whether the predetermined block (411) of the picture (12') is to be split into four child blocks (412) or not,

if the predetermined block (411) of the picture (12’) is to be split, but not to be split into four child blocks (412),

decoding a split direction flag (518) from the data stream (14) which indicates whether the predetermined block (41 1) of the picture (12’) is to be split vertically or horizontally, and

decoding a triple flag (519) from the data stream 14 which indicates whether the predetermined block (411) of the picture (12’) is to be split into three child blocks (412) or into two child blocks (412),

if the predetermined block (411) of the picture (12’) is to be split,

resuming the recursive multi-tree splitting for the child blocks (412) using even further flags of the splitting information (415),

decode the triple flag (519) from the data stream (14) by context adaptive entropy decoding using a third context (853) which

depends on

a number of splits of the recursive multi-tree splitting using which the predetermined block (411 ) is obtained, or

a size of the predetermined block (411 ), and/or

depends on whether, and discriminates between,

the split direction flag (518) indicating a horizontal split direction, and

the split direction flag (518) indicating a vertical split direction.

40. Apparatus (900) for decoding a picture (12’), configured to

partition the picture (12') into coding blocks (425) using recursive multi-tree splitting de-pending on splitting information (415) signaled in a data stream (14),

decode the picture (12’) from coding information (440) which is signaled in the data stream (14) and relates to the coding blocks (425),

wherein the apparatus (900) is configured to partition the picture (12’) into the coding blocks (425) depending on splitting information (415) signaled in a data stream (14) by

decoding a split flag (416) and a quad flag (417) of the splitting information (415) from the data stream (14), wherein the split flag (416) indicates whether a predetermined block (411) of the picture (12’) is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block (411) becoming one of the coding blocks (425), and the quad flag (417) indicates whether the predetermined block (41 1 ) of the picture (12’) is to be split into four child blocks (412) or not,

if the predetermined block (411) of the picture (12’) is to be split, but not to be split into four child blocks (412),

decoding one or more further flags (418) of the splitting information (415) from the data stream (14) which indicate whether the predetermined block (411) of the picture (12’) is to be split into two or three child blocks (412) vertically or horizontally,

if the predetermined block (41 1) of the picture (12') is to be split,

resuming the recursive multi-tree splitting for the child blocks (412) using even further flags of the splitting information (415),

wherein the apparatus (900) is configured to select one of a first mode and a second mode, and,

in the first mode, decode the quad flag (417) after the split flag (416) if the split flag (416) indicates that the predetermined block (411) of the picture (12’) is to be split, and

in the second mode, decode the split flag (416) after the quad flag (417) if the quad flag (417) indicates that the predetermined child block of the picture (12’) is not to be split into four child blocks (412).

41. Apparatus of claim 40, configured to

perform the selection depending on a mode signalization in the data stream (14).

42. Apparatus of claim 40, configured to

perform the selection backward adaptively.

43. Apparatus of claim 40, configured to

perform the selection depending on an evaluation of one or more of

block sizes of a set of previous coding blocks (425),

number of splits from which ai set of previously coding blocks (425) results,

a quantization parameter signaled in the data stream (14),

44. Apparatus for encoding a picture (12), configured to

partition the picture (12) into coding blocks (425) using recursive multi-tree splitting en-code splitting information (415) defining the partitioning in a data stream (14),

encode the picture (12) into coding information (440) which relates to the coding blocks (425) and encode the coding information (440) in the data stream (14),

wherein the apparatus is configured to encode the splitting information (415) in the data stream (14) by

encoding a split flag (416) of the splitting information (415) into the data stream (14) which indicates whether a predetermined block (411) of the picture (12) is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block (411) becoming one of the coding blocks (425),

if the split flag (416) indicates that the predetermined block (411) of the picture (12) is to be split,

encoding a quad flag (417) of the splitting information (415) into the data stream (14) which indicates whether the predetermined block (411) of the picture (12) is to be split into four child blocks (412) or not,

if the quad flag (417) indicates that the predetermined block (41 1) of the picture (12) is not to be split into four child blocks (412),

encoding one or more further flags (418) of the splitting information (415) into the data stream (14) which indicate whether the predetermined block (411) of the picture (12) is to be split into two or three child blocks (412) vertically or horizontally,

resuming the encoding the splitting information (415) for the child blocks (412) using even further flags of the splitting information (415).

45. Apparatus of claim 44, configured to

resume the encoding the splitting information (415) for the child blocks (412) using even further flags of the splitting information (415) by, for a predetermined child block of the child blocks (412),

encoding a further split flag (416) of the splitting information (415) into the data stream (14) which indicates whether the predetermined child block of the picture (12) is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined child block becoming a coding block,

if the further split flag (416) indicates that the predetermined child block of the picture (12) is to be split,

encoding a further quad flag (417) of the splitting information (415) into the data stream (14) which indicates whether the predetermined child block of the picture (12) is to be split into four child blocks (412) or not,

if the further quad flag (417) indicates that the predetermined child block of the picture (12) is not to be split into four child blocks (412),

encoding one or more further flags (418) of the splitting information (415) into the data stream (14) which indicate whether the predetermined child block of the picture (12) is to be split into two or three child blocks (412) vertically or horizontally,

resuming the encoding the splitting information (415) for the child blocks (412) of the predetermined child block using even even further flags of the splitting information (415).

46. Apparatus of claim 44 or 45, configured to

not encode into the data stream (14), depending on one or more criteria being fulfilled or not, one or more flags of the splitting information (415) which assume a predetermined flag state wherein the one or more flags of the splitting information (415) are to be inferred to assume the predetermined flag state depending on one or more criteria being fulfilled or not.

47. Apparatus of claim 46, wherein the one or more criteria relate to one or more of

child block area, child block width, child block height, a current split depth and a split line alignment with a picture (12) border.

48. Apparatus of any of the previous claims, configured to

start the recursive multi-tree splitting at each tree-root block of tree-root blocks into which the picture (12) is subdivided in rows and columns.

49. Apparatus of any of the previous claims, configured to

start the recursive multi-tree splitting at tree-root blocks into which the picture (12) is subdivided in rows and columns.

50. Apparatus of any of the previous claims, configured to

suppress the encoding of the quad flag (417) into the data stream (14), if a first predetermined criterion is fulfilled so that that the quad flag (417) is to be inferred to indicate that the predetermined block (411) of the picture (12) is not to be split into four child blocks (412) if the first predetermined criterion is fulfilled.

51. Apparatus of any of the previous claims, configured so that the a first predetermined criterion is fulfilled is the predetermined block (411 ) results from a non-quad split of a parent block.

52. Apparatus of any of the previous claims, configured to, in the encoding of one or more further flags (418) of the splitting information (415) into the data stream (14) which indicate whether the predetermined child block of the picture (12) is to be split into two or three child blocks (412) vertically or horizontally

encode a split direction flag (518) into the data stream (14) which indicates whether the predetermined block (411) of the picture (12) is to be split vertically or horizontally, and

encode a triple flag (519) into the data stream (14) which indicates whether the predetermined block (411 ) of the picture (12) is to be split into three child blocks (412) or into two child blocks (412).

53. Apparatus of claim 52, configured to

suppress the encoding of the split direction flag (518) into the data stream (14), if a second predetermined criterion is fulfilled, wheren the split direction flag (518) is to be inferred to indicate that the predetermined block (411 ) of the picture (12) is to be split vertically if the second predetermined criterion is fulfilled, and

, suppress the encoding of the split direction flag (518) into the data stream (14), if a third predetermined criterion is fulfilled wherein it is to be inferred that the split direction flag (518) indicates that the predetermined block (411) of the picture (12) is to be split horizontally, if the third predetermined criterion is fulfilled.

54. Apparatus of claim 53, wherein

the second predetermined criterion is fulfilled is halving the predetermined block (411) horizontally would yield a width falling below a predetermined minimum dimension, and

the third predetermined criterion is fulfilled if halving the predetermined block (411) vertically would yield a height falling below the predetermined minimum dimension.

55. Apparatus of any of claims 52 to 54, configured to

suppress the encoding of the triple flag (519) into the data stream (14), if a fourth predetermined criterion is fulfilled wherein the triple flag (519) is to be inferred to indicate that the predetermined block (41 1) of the picture (12) is to be split into two child blocks (412) if the fourth predetermined criterion is fulfilled.

56. Apparatus of any of claims 52 to 54, configured to

suppress the encoding of the triple flag (519) into the data stream (14), if a fourth predetermined criterion is fulfilled wherein the triple flag (519) I to be inferred to indicate that the predetermined block (411 ) of the picture (12) is to be split into two child blocks 412if a fourth predetermined criterion is fulfilled, and

suppress the encoding of the triple flag (519) into the data stream (14), if a fifth predetermined criterion is fulfilled wherein the triple flag (519) is to be inferred to indicate that the predetermined block (411) of the picture (12) is to be split into three child blocks (412) if the fifth predetermined criterion is fulfilled.

57. Apparatus of any of claims 55 and 56, wherein

the fourth predetermined criterion is fulfilled if trisecting the predetermined block (411) in a split direction indicated by the direction flag would yield a dimension of the predetermined

block (41 1) along the split direction which split falls below a predetermined minimum dimension.

58. Apparatus of any of claims 55 to 57, wherein

the fifth predetermined criterion is fulfilled if halving the predetermined block (411) in a split direction indicated by the direction flag would yield a dimension of the predetermined block (411) along the split direction which exceeds a predetermined maximum dimension.

59. Apparatus of any of the previous claims, configured to

resume the encoding the splitting information (415) for the child blocks (412) using even further flags of the splitting information (415) by, for a predetermined child block of the child blocks (412),

encoding a further quad flag (417) of the splitting information (415) into the data stream (14) which indicates whether the predetermined child block of the picture (12) is to be split into four child blocks (412) or not,

if the further quad flag (417) indicates that the predetermined child block of the picture (12) is not to be split into four child blocks (412),

encoding a further split flag (416) of the splitting information (415) into the data stream (14) which indicates whether the predetermined child block of the picture (12) is to be split, or not to be split thereby stopping the recursive multi-tree splitting with the predetermined child block becoming a coding block,

if the further split flag (416) indicates that the predetermined child block of the picture (12) is to be split,

encoding one or more further flags (418) of the splitting information (415) into the data stream (14) which indicate whether the predetermined child block of the picture (12) is to be split into two or three child blocks (412) vertically or horizontally,

resuming the encoding the splitting information (415) for the child blocks (412) of the predetermined child block using even even further flags of the splitting information (415).

60. Apparatus of any of the previous claims, configured to

suppress the encoding of the quad flag (417) into the data stream (14), if a first predetermined criterion is fulfilled wherein the quad flag (417) is to be inferred to indicate that the predetermined block (411 ) of the picture (12) is not to be split into four child blocks (412) if the first predetermined criterion is fulfilled, and

encode the split flag (416) of the splitting information (415) into the data stream (14) by context adaptive entropy encoding using a first context which depends on

whether the first predetermined criterion is fulfilled.

61. Apparatus of claim 60, wherein the first context additionally depends on

a number of splits of the recursive multi-tree splitting using which the predetermined block (411) is obtained, or

a size of the predetermined block (411).

62. Apparatus of claim 60, wherein the first context additionally depends on, and discriminates between,

a number of splits of the recursive multi-tree splitting using which the predetermined block (411) is obtained, is below a predetermined threshold number of splits, or

a size of the predetermined block (411) is above a predetermined threshold size.

63. Apparatus of any of claims 60 to 62, wherein the first context additionally depends on

a width of a coding block above the predetermined block (411 ), and

a height of a coding block to the left of the predetermined block (411 ).

64. Apparatus of any of claims 60 to 62, wherein the first context additionally depends on whether, and discriminates between,

a width of a coding block above the predetermined block (411) is smaller than a width of the predetermined block (411) and a height of a coding block to the left of the predetermined block (411) is smaller than a height of the predetermined block (411),

the width of the coding block above the predetermined block (41 1) is smaller than the width of the predetermined block (41 1) and the height of the coding block to the left of the predetermined block (411) is larger than the height of the predetermined block (411 ), and

the width of the coding block above the predetermined block (411) is smaller than the width of the predetermined block (411) and the height of the coding block to the left of the predetermined block (411) is larger than the height of the predetermined block (411) or the width of the coding block above the predetermined block (41 1 ) is larger than the width of the predetermined block (411 ) and the height of the coding block to the left of the predetermined block (411) is smaller than the height of the predetermined block (41 1).

65. Apparatus of any of the previous claims, configured to

perform the splitting into four child blocks (412) so that the four child blocks (412) are equally sized and arranged in a (2x2) array, and

perform the recursive multi-tree splitting using a depth first traversal order and traverse child blocks (412) resulting from splitting one parent block from left to right in case of a horizontal split, from top to bottom in case of a vertical split and in a row-wise raster can order from top left to bottom right in case of a splitting into four child blocks (412).

66. Apparatus of any of the previous claims, configured to

in the encoding of one or more further flags (418) of the splitting information (415) into the data stream (14) which indicate whether the predetermined child block of the picture (12) is to be split into two or three child blocks (412) vertically or horizontally

encode a split direction flag (518) into the data stream (14) which indicates whether the predetermined block (411 ) of the picture (12) is to be split vertically or horizontally, and

encode a triple flag (519) into the data stream (14) which indicates whether the predetermined block (411) of the picture (12) is to be split into three child blocks (412) or into two child blocks (412),

suppress the encoding of the quad flag (417) into the data stream (14), if a first predeter-mined criterion is fulfilled wherein the quad flag (417) is to be inferred to indicate that the predetermined block (411 ) of the picture (12) is not to be split into four child blocks (412) if the first predetermined criterion is fulfilled,

suppress the encoding of the split direction flag (518) into the data stream (14), if a second predetermined criterion is fulfilled wherein the split direction flag (518) is to be inferred to indicate that the predetermined block (411) of the picture (12) is to be split vertically if the second predetermined criterion is fulfilled, and suppress the encoding of the split direction flag (518) into the data stream (14), if a third predetermined criterion is fulfilled wherein the split direction flag (518) is inferred to indicate that the predetermined block (411) of the picture (12) is to be split horizontally if the third predetermined criterion is ful-filled, and

suppress the encoding of the triple flag (519) into the data stream (14), if a fourth predetermined criterion is fulfilled wherein the triple flag (519) is inferred to indicate that the predetermined block (411) of the picture (12) is to be split into two child blocks (412) if the fourth predetermined criterion is fulfilled,

encode the split flag (416) of the splitting information (415) into the data stream (14) by context adaptive entropy encoding using a first context which depends on

a sum of addends each of which is associated with, and assumes a non-zero value if, while being zero otherwise,

the first predetermined criterion is not fulfilled,

the second predetermined criterion is not fulfilled,

the third predetermined criterion is not fulfilled,

the second predetermined criterion is not fulfilled and the fourth predetermined criterion would not be fulfilled in case of a split direction indicated by the split direction flag (518) being horizontal, and

the third predetermined criterion is not fulfilled and the fourth predetermined criterion would not be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical, respectively.

67. Apparatus of any of the previous claims, configured to

in the encoding of one or more further flags (418) of the splitting information (415) into the data stream (14) which indicate whether the predetermined child block of the picture (12) is to be split into two or three child blocks (412) vertically or horizontally

encode a split direction flag (518) into the data stream (14) which indicates whether the predetermined block (411) of the picture (12) is to be split vertically or horizontally, and

encode a triple flag (519) into the data stream (14) which indicates whether the predetermined block (411) of the picture (12) is to be split into three child blocks (412) or into two child blocks (412),

suppress the encoding of the quad flag (417) into the data stream (14), if a first predetermined criterion is fulfilled wherein the quad flag (417) is to be inferred to indicate that the predetermined block (411) of the picture (12) is not to be split into four child blocks (412) if the first predetermined criterion is fulfilled,

suppress the encoding of the split direction flag (518) into the data stream (14), if a sec-ond predetermined criterion is fulfilled wherein the split direction flag (518) is to be inferred to indicate that the predetermined block (411) of the picture (12) is to be split vertically if the second predetermined criterion is fulfilled, and suppress the encoding of the split direction flag (518) into the data stream (14), if a third predetermined criterion is fulfilled wherein the split direction flag (518) is inferred to indicate that the predetermined block (411) of the picture (12) is to be split horizontally if the third predetermined criterion is fulfilled, and

suppress the encoding of the triple flag (519) into the data stream (14), if a fourth predetermined criterion is fulfilled wherein the triple flag (519) I to be inferred to indicate that the predetermined block (411) of the picture (12) is to be split into two child blocks 412if a fourth predetermined criterion is fulfilled, and suppress the encoding of the triple flag (519) into the data stream (14), if a fifth predetermined criterion is fulfilled wherein the triple flag (519) is to be inferred to indicate that the predetermined block (411) of the picture (12) is to be split into three child blocks (412) if the fifth predetermined criterion is fulfilled,

encode the split flag (416) of the splitting information (415) into the data stream (14) by context adaptive entropy encoding using a first context which depends on

a sum of addends each of which is associated with, and assumes a non-zero value if, while being zero otherwise,

the first predetermined criterion is not fulfilled,

the second predetermined criterion is not fulfilled, and the fifth predetermined criterion would not be fulfilled in case of the split direction indicated by the split direction flag (518) being horizontal,

the third predetermined criterion is not fulfilled, and the fifth predetermined criterion would not be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical,

the second predetermined criterion is not fulfilled and the fourth predetermined criterion would not be fulfilled in case of the split direction indicated by the split direction flag (518) being horizontal, and

the third predetermined criterion is not fulfilled and the fourth predetermined criterion would not be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical, respectively.

68. Apparatus of one of claims 66 and 67, wherein the first context additionally depends on whether, and discriminates between,

a third of the sum of addends plus one is zero, one and two, wherein the non-zero value of the addend associated with the first predetermined criterion being not fulfilled is two, and the non-zero values of the other addends are one.

69. Apparatus of any of claims 66 to 68, wherein the first context additionally depends on

a width of a coding block above the predetermined block (411), and

a height of a coding block to the left of the predetermined block (411).

70. Apparatus of any of claims 66 to 68, wherein the first context additionally depends on whether, and discriminates between,

a width of a coding block above the predetermined block (411) is smaller than a width of the predetermined block (411) and a height of a coding block to the left of the predetermined block (41 1) is smaller than a height of the predetermined block (411),

the width of the coding block above the predetermined block (411) is smaller than the width of the predetermined block (411) and the height of the coding block to the left of the predetermined block (41 1) is larger than the height of the predetermined block (411), and

the width of the coding block above the predetermined block (411) is smaller than the width of the predetermined block (411) and the height of the coding block to the left of the predetermined block (41 1) is larger than the height of the predetermined block (411) or the width of the coding block above the predetermined block (411) is larger than the width of the predetermined block (411 ) and the height of the coding block to the left of the predetermined block (411) is smaller than the height of the predetermined block (411).

71. Apparatus of any of the previous claims, configured to, in the encoding of one or more further flags (418) of the splitting information (415) into the data stream (14) which indicate whether the predetermined child block of the picture (12) is to be split into two or three child blocks (412) vertically or horizontally

encode a split direction flag (518) into the data stream (14) which indicates whether the predetermined block (41 1) of the picture (12) is to be split vertically or horizontally, if neither a second nor a third predetermined criterion is fulfilled,

suppress the encoding of the split direction flag (518) into the data stream (14) wherein same is to be inferred to indicate that the predetermined block (411) of the picture (12) is to be split vertically, if the second predetermined criterion is fulfilled, and

suppress the encoding of the split direction flag (518) into the data stream (14) wherein same is to be inferred to indicate that the predetermined block (411 ) of the picture (12) is to be split horizontally, if the third predetermined criterion is fulfilled,

encode a triple flag (519) into the data stream (14) which indicates whether the predetermined block (41 1 ) of the picture (12) is to be split into three child blocks (412) or into two child blocks (412), if a fourth predetermined criterion is not fulfilled, and

suppress the encoding of the triple flag (519) into the data stream (14) wherein same is to be inferred to indicate that the predetermined block (411) of the picture (12) is to be split into two child blocks (412), if the fourth predetermined criterion is fulfilled,

encode the split direction flag (518) into the data stream (14) by context adaptive entropy encoding using a second context (552) which depends on whether, and discriminates be-tween,

the fourth predetermined criterion would not neither be fulfilled in case of a split direction indicated by the split direction flag (518) being horizontal nor in case of the split direction indicated by the split direction flag (518) being vertical or be fulfilled both in case of a split direction indicated by the split direction flag (518) being horizontal as well as in case of the split direction indicated by the split direction flag (518) being vertical,

the fourth predetermined criterion would be fulfilled in case of the split direction indicated by the split direction flag (518) being horizontal and not be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical, and

the fourth predetermined criterion would not be fulfilled in case of the split direction indicated by the split direction flag (518) being horizontal and be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical.

72. Apparatus of any of the previous claims, configured to, in the encoding of one or more further flags (418) of the splitting information (415) into the data stream (14) which indicate whether the predetermined child block of the picture (12) is to be split into two or three child blocks (412) vertically or horizontally

encode a split direction flag (518) into the data stream (14) which indicates whether the predetermined block (411) of the picture (12) is to be split vertically or horizontally, if neither a second nor a third predetermined criterion is fulfilled,

suppress the encoding of the split direction flag (518) into the data stream (14) wherein same is to be inferred to indicate that the predetermined block (411) of the picture (12) is to be split vertically, if the second predetermined criterion is fulfilled, and

suppress the encoding of the split direction flag (518) into the data stream (14) wherein same is to be inferred to indicate that the predetermined block (411) of the picture (12) is to be split horizontally, if the third predetermined criterion is fulfilled,

encode a triple flag (519) into the data stream (14) which indicates whether the predetermined block (41 1) of the picture (12) is to be split into three child blocks (412) or into two child blocks (412), if fourth and fifth predetermined criteria are not fulfilled, and

suppress the encoding of the triple flag (519) into the data stream (14) wherein same is to be inferred to indicate that the predetermined block (411) of the picture (12) is to be split into two child blocks (412), if the fourth predetermined criterion is fulfilled, and

suppress the encoding of the triple flag (519) into the data stream (14) wherein same is to be inferred to indicate that the predetermined block (411) of the picture (12) is to be split into three child blocks (412) and suppress the encoding of the triple flag (519) into the data stream (14), if the fifth predetermined criterion is fulfilled,

encode the split direction flag (518) into the data stream (14) by context adaptive entropy encoding using a second context (552) which depends on whether, and discriminates be-tween,

a first number of criteria among the fourth and fifth predetermined criteria which would be fulfilled in case of a split direction indicated by the split direction flag (518) being horizontal equals a second number of criteria among the fourth and fifth predetermined criteria which would be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical,

the first number being greater than the second number, and

the first number being smaller than the second number.

73. Apparatus for encoding a picture (12), configured to

partition the picture (12) into coding blocks (425) using recursive multi-tree splitting and encode splitting information (415) defining the partitioning in a data stream (14),

encode the picture (12) into coding information (440) which relates to the coding blocks (425) and encode the coding information (440) in the data stream (14),

wherein the apparatus is configured to encode the splitting information (415) in the data stream (14) by

encoding a split flag (416) and a quad flag (417) of the splitting information (415) into the data stream (14), wherein the split flag (416) indicates whether a predetermined block (411) of the picture (12) is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block (411) becoming one of the coding blocks (425), and the quad flag (417) indicates whether the predetermined block (41 1) of the picture (12) is to be split into four child blocks (412) or not,

if the predetermined block (411) of the picture (12) is to be split, but not to be split into four child blocks (412),

encoding a split direction flag (518) into the data stream (14) which indicates whether the predetermined block (411) of the picture (12) is to be split vertically or horizontally, if neither a second nor a third predetermined criterion is fulfilled,

suppress the encoding of the split direction flag (518) if the second predetermined criterion is fulfilled wherein same is to be inferred to indicate that predetermined block (411 ) of the picture (12) is to be split vertically, If the second predetermined criterion is fulfilled, and

suppress the encoding of the split direction flag (518) if the third predetermined criterion Is fulfilled wherein same is to be inferred to indicate that the predetermined block (411) of the picture (12) is to be split horizontally, if the third predetermined criterion is fulfilled,

encoding a triple flag (519) into the data stream (14) which indicates whether the predetermined block (411) of the picture (12) is to be split into three child blocks (412) or into two child blocks (412), if a fourth predetermined criterion is not fulfilled, and

suppress the encoding the triple flag (519) if the fourth predetermined criterion is fulfilled wherein same is to be inferred to indicate that the predetermined block (411) of the picture (12) is to be split into two child blocks (412), if the fourth predetermined criterion is fulfilled,

if the predetermined block (411) of the picture (12) is to be split,

resuming the encoding of the splitting information (415) for the child blocks (412) using even further flags of the splitting information (415),

encode the split direction flag (518) into the data stream (14) by context adaptive entropy encoding using a second context (552) which depends on whether, and discriminates between,

the fourth predetermined criterion would not neither be fulfilled in case of a split direction indicated by the split direction flag (518) being horizontal nor in case of the split direction indicated by the split direction flag (518) being vertical or be fulfilled both in case of a split direction indicated by the split direction flag (518) being horizontal as well as in case of the split direction indicated by the split direction flag (518) being vertical,

the fourth predetermined criterion would be fulfilled in case of the split direction indicated by the split direction flag (518) being horizontal and not be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical, and

the fourth predetermined criterion would not be fulfilled in case of the split direction indicated by the split direction flag (518) being horizontal and be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical.

74. Apparatus for encoding a picture (12), configured to

partition the picture (12) into coding blocks .(425) using recursive multi-tree splitting and encode splitting information (415) defining the partitioning in a data stream (14),

encode the picture (12) into coding information (440) which is signaled in the data stream (14) and relates to the coding blocks (425) and encode the coding information (440) in the data stream (14),

wherein the apparatus is configured to partition the picture (12) into the coding blocks (425) depending on splitting information (415) signaled in a data stream (14) by

encoding a split flag (416) and a quad flag (417) of the splitting information (415) into the data stream (14), wherein the split flag (416) indicates whether a predetermined block (411) of the picture (12) is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block (411) becoming one of the coding blocks (425), and the quad flag (417) indicates whether the predetermined block (411) of the picture (12) is to be split into four child blocks (412) or not,

if the predetermined block (411) of the picture (12) is to be split, but not to be split into four child blocks (412),

encoding a split direction flag (518) into the data stream (14) which indicates whether the predetermined block (411) of the picture (12) is to be split vertically or horizontally, if neither a second nor a third predetermined criterion is fulfilled,

suppress the encoding of the split direction flag (518) if the second predetermined criterion is fulfilled wherein same is to be inferred to indicate that predetermined block (411) of the picture (12) is to be split vertically, if the second predetermined criterion is fulfilled, and

suppress the encoding of the split direction flag (518) if the third predetermined criterion is fulfilled wherein same is to be inferred to indicate that the predetermined block (411) of the picture (12) is to be split horizontally, if the third predetermined criterion is fulfilled,

encoding a triple flag (519) into the data stream (14) which indicates whether the predetermined block (411) of the picture (12) is to be split into three child blocks (412) or into two child blocks (412), if fourth and fifth predetermined criteria are not fulfilled, and

suppress the encoding the triple flag (519) if the fourth predetermined criterion is fulfilled wherein same is to be inferred to indicate that the predetermined block (411) of the picture (12) is to be split into two child blocks (412), if the fourth predetermined criterion is fulfilled, and

suppress the encoding the triple flag (519) if the fifth predetermined criterion is fulfilled, wherein the triple flag (519) is to be inferred to indicate that the predetermined block (41 1) of the picture (12) is to be split into three child blocks (412), if the fifth predetermined criterion is fulfilled,

if the predetermined block (411) of the picture (12) is to be split,

resuming the encoding the splitting information (415) for the child blocks (412) using even further flags of the splitting information (415),

encode the split direction flag (518) into the data stream (14) by context adaptive entropy encoding using a second context (552) which depends on whether, and discriminates between,

a first number of criteria among the fourth and fifth predetermined criteria which would be fulfilled in case of a split direction indicated by the split direction flag (518) being horizontal equals a second number of criteria among the fourth and fifth predetermined criteria which would be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical,

the first number being greater than the second number, and

the first number being smaller than the second number.

75. Apparatus of one of the claims 71 or 73 or 74, wherein the second context (552) additionally depends on whether, and discriminates between,

a width of the predetermined block (411) equaling a height of the current block, and

the width of the predetermined block (411 ) being larger than the height of the current block, and

the width of the predetermined block (411) being smaller than the height of the current block.

76. Apparatus of claim 71 or any of the claims 73 to 75, wherein the second context (552),

if the fourth predetermined criterion would not neither be fulfilled in case of a split direction indicated by the split direction flag (518) being horizontal nor in case of the split direction indicated by the split direction flag (518) being vertical or be fulfilled both in case of a split direction indicated by the split direction flag (518) being horizontal as well as in case of the split direction indicated by the split direction flag (518) being vertical, additionally depends on whether, and discriminates between,

a width of the predetermined block (411) equaling a height of the current block, and

the width of the predetermined block (411 ) being larger than the height of the current block, and

the width of the predetermined block (411) being smaller than the height of the current block, and

if the fourth predetermined criterion would be fulfilled in either one of the case of the split direction indicated by the split direction flag (518) being horizontal and the case of the split direction indicated by the split direction flag (518) being vertical, is non-discriminative between,

the width of the predetermined block (411) equaling the height of the current block, and

the width of the predetermined block (41 1) being larger than the height of the current block, and

the width of the predetermined block (411) being smaller than the height of the current block.

77. Apparatus of claim 71 or 73, wherein the second context (552) additionally depends on whether, and discriminates between,

a first ratio between a width of the predetermined block (41 1) and a width of a coding block above the predetermined block (41 1) equaling a second ratio between a height of the current block and a height of a coding block to the left of the predetermined block (411), and

the first ratio being larger than the second ratio, and

the first ratio being smaller than the second ratio.

78. Apparatus of claim 71 or any previous claim 73, wherein the second context (552),

if the fourth predetermined criterion would not neither be fulfilled in case of a split direction indicated by the split direction flag (518) being horizontal nor in case of the split direction indicated by the split direction flag (518) being vertical or be fulfilled both in case of a split direction indicated by the split direction flag (518) being horizontal as well as in case of the split direction indicated by the split direction flag (518) being vertical, additionally depends on whether, and discriminates between,

a first ratio between a width of the predetermined block (411) and a width of a coding block above the predetermined block (411) equaling a second ratio be-

tween a height of the current block and a height of a coding block to the left of the predetermined block (411), and

the first ratio being larger than the second ratio, and

the first ratio being smaller than the second ratio,

if the fourth predetermined criterion would be fulfilled in either one of the case of the split direction indicated by the split direction flag (518) being horizontal and the case of the split direction indicated by the split direction flag (518) being vertical, is non-discriminative between,

a first ratio between a width of the predetermined block (411) and a width of a coding block above the predetermined block (411) equaling a second ratio between a height of the current block and a height of a coding block to the left of the predetermined block (411), and

the first ratio being larger than the second ratio, and

the first ratio being smaller than the second ratio.

79. Apparatus of claim 71 or any of the claims 73 to 78, wherein the second context (552) is non-discriminative between,

whether the fourth predetermined criterion would neither be fulfilled in case of the split direction indicated by the split direction flag (518) being horizontal nor in case of the split direction indicated by the split direction flag (518) being vertical and

whether the fourth predetermined criterion would be fulfilled both in case of a split direction indicated by the split direction flag (518) being horizontal as well as in case of the split direction indicated by the split direction flag (518) being vertical.

80. Apparatus of claim 71 or any of the claims 73 to 79, configured to

encode the triple flag (519) into the data stream (14) by context adaptive entropy encoding using a third context (853) which depends on whether, and discriminates between i

a number of splits of the recursive multi-tree splitting using which the predetermined block (411) is obtained, or

a size of the predetermined block (411).

81. Apparatus of claim 71 or any of the claims 73 to 80, configured to

encode the triple flag (519) into the data stream (14) by context adaptive entropy encoding using a third context (853) which depends on whether, and discriminates between,

the split direction flag (518) indicating a horizontal split direction, and

the split direction flag (518) indicating a vertical split direction.

82. Apparatus for encoding a picture (12), configured to

partition the picture (12) into coding blocks (425) using recursive multi-tree splitting and encode splitting information (415) defining the partitioning in a data stream (14),

encode the picture (12) into coding information (440) which relates to the coding blocks (425) and encode the coding information (440) in the data stream (14),

wherein the apparatus is configured to encode the splitting information (415) into the data stream (14) by

encoding a split flag (416) and a quad flag (417) of the splitting information (415) into the data stream (14), wherein the split flag (416) indicates whether a predetermined block (411) of the picture (12) is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block (411) becoming one of the coding blocks (425), and the quad flag (417) indicates whether the predetermined block (411) of the picture (12) is to be split into four child blocks (412) or not,

if the predetermined block (411) of the picture (12) is to be split, but not to be split into four child blocks (412),

encoding a split direction flag (518) into the data stream (14) which indicates whether the predetermined block (411) of the picture (12) is to be split vertically or horizontally, and

encoding a triple flag (519) into the data stream (14) which indicates whether the predetermined block (41 1) of the picture (12) is to be split into three child blocks (412) or into two child blocks (412),

if the predetermined block (411) of the picture (12) is to be split,

resuming the encoding the splitting information (415) for the child blocks (412) using even further flags of the splitting information (415),

encode the triple flag (519) into the data stream (14) by context adaptive entropy encoding using a third context (853) which

depends on

a number of splits of the recursive multi-tree splitting using which the predetermined block (411) is obtained, or

a size of the predetermined block (411), and/or

depends on whether, and discriminates between

the split direction flag (518) indicating a horizontal split direction, and

the split direction flag (518) indicating a vertical split direction.

83. Apparatus for encoding a picture (12), configured to

partition the picture (12) into coding blocks (425) using recursive multi-tree splitting and encode splitting information (415) defining the partitioning in a data stream (14),

encode the picture (12) into coding information (440) which relates to the coding blocks (425) and encode the coding information (440) in the data stream (14),

wherein the apparatus is configured to encode the splitting information (415) into the data stream (14) by

encoding a split flag (416) and a quad flag (417) of the splitting information (415) into the data stream (14), wherein the split flag (416) indicates whether a predetermined block (411) of the picture (12) is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block (411) becoming one of the coding blocks (425), and the quad flag (417) indicates whether the predetermined block (411) of the picture (12) is to be split into four child blocks (412) or not,

if the predetermined block (411) of the picture (12) is to be split, but not to be split into four child blocks (412),

encoding one or more further flags (418) of the splitting information (415) into the data stream (14) which indicate whether the predetermined block (41 1) of the picture (12) is to be split into two or three child blocks (412) vertically or horizontally,

if the predetermined block (411) of the picture (12) is to be split,

resuming the encoding the splitting information (415) for the child blocks (412) using even further flags of the splitting information (415),

wherein the apparatus is configured to select one of a first mode and a second mode, and

in the first mode, encode the quad flag (417) after the split flag (416) if the split flag (416) indicates that the predetermined block (411) of the picture (12) is to be split, and

in the second mode, encode the split flag (416) after the quad flag (417) if the quad flag (417) indicates that the predetermined child block of the picture (12) is not to be split into four child blocks (412).

84. Apparatus of claim 83, configured to

perform the selection depending on a mode signalization in the data stream (14).

85. Apparatus of claim 83, configured to

perform the selection backward adaptively.

86. Apparatus of claim 83, configured to

perform the selection depending on an evaluation of one or more of

block sizes of a set of previously coding blocks (425),

number of splits from which a set of previously coding blocks (425) results,

a quantization parameter signaled in the data stream (14).

87. Method for decoding a picture (12’), comprising:

partitioning the picture (12') into coding blocks (425) using recursive multi-tree splitting depending on splitting information (415) signaled in a data stream (14),

decoding the picture (12') from coding information (440) which is signaled in the data stream (14) and relates to the coding blocks (425),

wherein the method comprises partitioning the picture (12') into the coding blocks (425) depending on splitting information (415) signaled in a data stream (14) by

decoding a split flag (416) of the splitting information (415) from the data stream (14) which indicates whether a predetermined block (411) of the picture (12’) is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block (411) becoming one of the coding blocks (425),

if the split flag (416) indicates that the predetermined block (411) of the picture (12') is to be split,

decoding a quad flag (417) of the splitting information (415) from the data stream (14) which indicates whether the predetermined block (411) of the picture (12’) is to be split into four child blocks (412) or not,

if the quad flag (417) indicates that the predetermined block (411) of the picture (12’) is not to be split into four child blocks (412),

decoding one or more further flags (418) of the splitting information (415) from the data stream (14) which indicate whether the predetermined block (411) of the picture (12’) is to be split into two or three child blocks (412) vertically or horizontally,

resuming the recursive multi-tree splitting for the child blocks (412) using even further flags of the splitting information (415).

88. Method for decoding a picture (12’), comprising

partitioning the picture (12’) into coding blocks (425) using recursive multi-tree splitting depending on splitting information (415) signaled in a data stream (14),

decoding the picture (12’) from coding information (440) which is signaled in the data stream (14) and relates to the coding blocks (425),

wherein the method comprises partitioning the picture (12’) into the coding blocks (425) depending on splitting information (415) signaled in a data stream (14) by

decoding a split flag (416) and a quad flag (417) of the splitting information (415) from the data stream (14), wherein the split flag (416) indicates whether a predetermined block (411) of the picture (12’) is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block (411) becoming one of the coding blocks (425), and the quad flag (417) indicates whether the predetermined block (41 1) of the picture (12’) is to be split into four child blocks (412) or not,

if the predetermined block (41 1) of the picture (12’) is to be split, but not to be split into four child blocks (412),

decoding a split direction flag (518) from the data stream (14) which indicates whether the predetermined block (411) of the picture (12’) is to be split vertically or horizontally, if neither a second nor a third predetermined criterion is fulfilled,

inferring that the split direction flag (518) indicates that the predetermined block (41 1) of the picture (12’) is to be split vertically, if the second predetermined criterion is fulfilled, and

inferring that the split direction flag (518) indicates that the predetermined block (41 1) of the picture (12’) is to be split horizontally, if the third predetermined criterion is fulfilled,

decoding a triple flag (519) from the data stream (14) which indicates whether the predetermined block (41 1 ) of the picture (12’) is to be split into three child blocks (412) or into two child blocks (412), if a fourth predetermined criterion is not fulfilled, and

inferring that the triple flag (519) indicates that the predetermined block (411) of the picture (12’) is to be split into two child blocks (412), if the fourth predetermined criterion is fulfilled,

if the predetermined block (411) of the picture (12’) is to be split,

resuming the recursive multi-tree splitting for the child blocks (412) using even further flags of the splitting information (415),

decoding the split direction flag (518) from the data stream (14) by context adaptive entro-py decoding using a second context (552) which depends on whether, and discriminates between,

the fourth predetermined criterion would not neither be fulfilled in case of a split direction indicated by the split direction flag (518) being horizontal nor in case of the split direction indicated by the split direction flag (518) being vertical or be fulfilled both in case of a split direction indicated by the split direction flag (518) being horizontal as well as in case of the split direction indicated by the split direction flag (518) being vertical,

the fourth predetermined criterion would be fulfilled in case of the split direction indicated by the split direction flag (518) being horizontal and not be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical, and

the fourth predetermined criterion would not be fulfilled in case of the split direction indicated by the split direction flag (518) being horizontal and be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical.

89. Method for decoding a picture (12’), comprising:

partitioning the picture (12’) into coding blocks (425) using recursive multi-tree splitting depending on splitting information (415) signaled in a data stream (14),

decoding the picture (12’) from coding information (440) which is signaled in the data stream (14) and relates to the coding blocks (425),

wherein the method comprises partitioning the picture (12’) into the coding blocks (425) depending on splitting information (415) signaled in a data stream (14) by

decoding a split flag (416) and a quad flag (417) of the splitting information (415) from the data stream (14), wherein the split flag (416) indicates whether a predetermined block (411 ) of the picture (12’) is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block (411 ) becoming one of the coding blocks (425), and the quad flag (417) indicates whether the predetermined block (41 1 ) of the picture (12') is to be split into four child blocks (412) or not,

if the predetermined block (411) of the picture (12’) is to be split, but not to be split into four child blocks (412),

decoding a split direction flag (518) from the data stream (14) which indicates whether the predetermined block (411) of the picture (12’) is to be split vertically or horizontally, if neither a second nor a third predetermined criterion is fulfilled,

inferring that the split direction flag (518) indicates that the predetermined block (411 ) of the picture (12’) is to be split vertically, if the second predetermined criterion is fulfilled, and

inferring that the split direction flag (518) indicates that the predetermined block (411) of the picture (12’) is to be split horizontally, if the third predetermined criterion is fulfilled,

decoding a triple flag (519) from the data stream (14) which indicates whether the predetermined block (411) of the picture (12’) is to be split into three child blocks (412) or into two child blocks (412), if a fourth predetermined criterion is not fulfilled, and

inferring that the triple flag (519) indicates that the predetermined block (41 1 ) of the picture (12’) is to be split into two child blocks (412), if the fourth predetermined criterion is fulfilled, and that the triple flag (519) Indicates that the predetermined block (411) of the picture (12') is to be split into three child blocks (412) and suppress the decoding of the triple flag (519) from the data stream (14), if a fifth predetermined criterion is fulfilled,

if the predetermined block (41 1) of the picture (12’) is to be split,

resuming the recursive multi-tree splitting for the child blocks (412) using even further flags of the splitting information (415),

decoding the split direction flag (518) from the data stream (14) by context adaptive entropy decoding using a second context (552) which depends on whether, and discriminates between,

a first number of criteria among the fourth and fifth predetermined criteria which would be fulfilled in case of a split direction indicated by the split direction flag (518) being horizontal equals a second number of criteria among the fourth and fifth predetermined criteria which would be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical,

the first number being greater than the second number, and

the first number being smaller than the second number.

90. Method for decoding a picture (12’), comprising:

partitioning the picture (12’) into coding blocks (425) using recursive multi-tree splitting depending on splitting information (415) signaled in a data stream (14),

decoding the picture (12') from coding information (440) which is signaled in the data stream (14) and relates to the coding blocks (425),

wherein the method comprises partitioning the picture (12’) into the coding blocks (425) depending on splitting information (415) signaled in a data stream (14) by

decoding a split flag (416) and a quad flag (417) of the splitting information (415) from the data stream (14), wherein the split flag (416) indicates whether a predetermined block (411) of the picture (12’) is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block (411) becoming one of the coding blocks (425), and the quad flag (417) indicates whether the predetermined block (411) of the picture (12’) is to be split into four child blocks (412) or not,

if the predetermined block (411) of the picture (12’) is to be split, but not to be split into four child blocks (412),

decoding a split direction flag (518) from the data stream (14) which indicates whether the predetermined block (411) of the picture (12’) is to be split vertically or horizontally, and

decoding a triple flag (519) from the data stream (14) which indicates whether the predetermined block (411) of the picture (12’) is to be split into three child blocks (412) or into two child blocks (412),

if the predetermined block (411) of the picture (12') is to be split,

resuming the recursive multi-tree splitting for the child blocks (412) using even further flags of the splitting information (415),

decoding the triple flag (519) from the data stream (14) by context adaptive entropy de-coding using a third context (853) which

depends on

a number of splits of the recursive multi-tree splitting using which the predetermined block (41 1) is obtained, or

a size of the predetermined block (41 1 ), and/or

depends on whether, and discriminates between,

the split direction flag (518) indicating a horizontal split direction, and

the split direction flag (518) indicating a vertical split direction.

91. Method for decoding a picture (12’), comprising:

partitioning the picture (12’) into coding blocks (425) using recursive multi-tree splitting depending on splitting information (415) signaled in a data stream (14),

decoding the picture (12') from coding information (440) which is signaled in the data stream (14) and relates to the coding blocks (425) i

wherein the method comprises partitioning the picture (12’) into the coding blocks (425) depending on splitting information (415) signaled in a data stream (14) by

decoding a split flag (416) and a quad flag (417) of the splitting information (415) from the data stream (14), wherein the split flag (416) indicates whether a predetermined block (411 ) of the picture (12’) is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block (411) becoming one of the coding blocks (425), and the quad flag (417) indicates whether the predetermined block (41 1) of the picture (12’) is to be split into four child blocks (412) or not,

if the predetermined block (411) of the picture (12’) is to be split, but not to be split into four child blocks (412),

decoding one or more further flags (418) of the splitting information (415) from the data stream (14) which indicate whether the predetermined block (411 ) of the picture (12’) is to be split into two or three child blocks (412) vertically or horizontally,

if the predetermined block (41 1 )- of the picture (12’) is to be split,

resuming the recursive multi-tree splitting for the child blocks (412) using even further flags of the splitting information (415),

wherein the method comprises selecting one of a first mode and a second mode, and,

in the first mode, decode the quad flag (417) after the split flag (416) if the split flag (416) indicates that the predetermined block (41 1) of the picture (12') is to be split, and

in the second mode, decode the split flag (416) after the quad flag (417) if the quad flag (417) indicates that the predetermined child block of the picture (12’) is not to be split into four child blocks (412).

92. Method for encoding a picture (12), performed by an apparatus of claim 44.

93. Method for encoding a picture (12), performed by an apparatus of claim 73.

94. Method for encoding a picture (12), performed by an apparatus of claim 74.

95. Method for encoding a picture (12), performed by an apparatus of claim 82:

96. Method for encoding a picture (12), performed by an apparatus of claim 83.

97 Method for encoding a picture (12), comprising

partitioning the picture (12) into coding blocks (425) using recursive multi-tree splitting and encoding splitting information (415) defining the partitioning in a data stream (14),

encoding the picture (12) into coding information (440) which relates to the coding blocks (425) and encoding the coding information (440) in the data stream (14),

wherein the method comprises encoding the splitting information (415) in the data stream (14) by

encoding a split flag (416) of the splitting information (415) into the data stream (14) which indicates whether a predetermined block (411) of the picture (12) is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block (411) becoming one of the coding blocks (425),

if the split flag (416) indicates that the predetermined block (411) of the picture (12) is to be split,

encoding a quad flag (417) of the splitting information (415) into the data stream (14) which indicates whether the predetermined block (411) of the picture (12) is to be split into four child blocks (412) or not,

if the quad flag (417) indicates that the predetermined block (41 1) of the picture (12) is not to be split into four child blocks (412),

encoding one or more further flags (418) of the splitting information (415) into the data stream (14) which indicate whether the predetermined block (411) of the picture (12) is to be split into two or three child blocks (412) vertically or horizontally,

resuming the encoding the splitting information (415) for the child blocks (412) using even further flags of the splitting information (415).

98. Method for encoding a picture (12), comprising

partitioning the picture (12) into coding blocks (425) using recursive multi-tree splitting and encoding splitting information (415) defining the partitioning in a data stream (14),

encoding the picture (12) into coding information (440) which relates to the coding blocks (425) and encode the coding information (440) in the data stream (14),

wherein the method comprises encoding the splitting information (415) in the data stream (14) by

encoding a split flag (416) and a quad flag (417) of the splitting information (415) into the data stream (14), wherein the split flag (416) indicates whether a predetermined block (41 1) of the picture (12) is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block (411) becoming one of the coding blocks (425), and the quad flag (417) indicates whether the predetermined block (411) of the picture (12) is to be split into four child blocks (412) or not,

if the predetermined block (41 1) of the picture (12) is to be split, but not to be split into four child blocks (412),

encoding a split direction flag (518) into the data stream (14) which indicates whether the predetermined block (411) of the picture (12) is to be split vertically or horizontally, if neither a second nor a third predetermined criterion is fulfilled,

suppress the encoding of the split direction flag (518) if the second predetermined criterion is fulfilled wherein same is to be inferred to indicate that predetermined block (411) of the picture (12) is to be split vertically, if the second predetermined criterion is fulfilled, and

suppressing the encoding of the split direction flag (518) if the third predetermined criterion is fulfilled wherein same is to be inferred to indicate that the predetermined block (411 ) of the picture (12) is to be split horizontally, if the third predetermined criterion is fulfilled,

encoding a triple flag (519) into the data stream (14) which indicates whether the predetermined block (411) of the picture (12) is to be split into three child blocks (412) or into two child blocks (412), if a fourth predetermined criterion is not fulfilled, and

suppressing the encoding the triple flag (519) if the fourth predetermined criterion is fulfilled wherein same is to be inferred to indicate that the predetermined block (41 1 ) of the picture (12) is to be split into two child blocks (412), if the fourth predetermined criterion is fulfilled,

if the predetermined block (41 1) of the picture (12) is to be split,

resuming the encoding of the splitting information (415) for the child blocks (412) using even further flags of the splitting information (415),

encoding the split direction flag (518) into the data stream (14) by context adaptive entropy encoding using a second context (552) which depends on whether, and discriminates between,

the fourth predetermined criterion would not neither be fulfilled in case of a split direction indicated by the split direction flag (518) being horizontal nor in case of the split direction indicated by the split direction flag (518) being vertical or be fulfilled both in case of a split direction indicated by the split direction flag (518) being horizontal as well as in case of the split direction indicated by the split direction flag (518) being vertical,

the fourth predetermined criterion would be fulfilled in case of the split direction indicated by the split direction flag (518) being horizontal and not be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical, and

the fourth predetermined criterion would not be fulfilled in case of the split direction indicated by the split direction flag (518) being horizontal and be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical.

99. Method for encoding a picture (12), comprising

partitioning the picture (12) into coding blocks (425) using recursive multi-tree splitting and encoding splitting information (415) defining the partitioning in a data stream (14),

encoding the picture (12) into coding information (440) which is signaled in the data stream (14) and relates to the coding blocks (425) and encode the coding information (440) in the data stream (14),

wherein the method comprises partitioning the picture (12) into the coding blocks (425) depending on splitting information (415) signaled in a data stream (14) by

encoding a split flag (416) and a quad flag (417) of the splitting information (415) into the data stream (14), wherein the split flag (416) indicates whether a predetermined block (41 1) of the picture (12) is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block (411) becoming one of the coding blocks (425), and the quad flag (417) indicates whether the predetermined block (41 1) of the picture (12) is to be split into four child blocks (412) or not,

if the predetermined block (41 1) of the picture (12) is to be split, but not to be split into four child blocks (412),

encoding a split direction flag (518) into the data stream (14) which indicates whether the predetermined block (411) of the picture (12) is to be split vertically or horizontally, if neither a second nor a third predetermined criterion is fulfilled,

suppressing the encoding of the split direction flag (518) if the second predetermined criterion is fulfilled wherein same is to be inferred to indicate that predetermined block (411) of the picture (12) is to be split vertically, if the second predetermined criterion is fulfilled, and

suppressing the encoding of the split direction flag (518) if the third predetermined criterion is fulfilled wherein same is to be inferred to indicate that the predetermined block (411) of the picture (12) is to be split horizontally, if the third predetermined criterion is fulfilled,

encoding a triple flag (519) into the data stream (14) which indicates whether the predetermined block (411) of the picture (12) is to be split into three child blocks (412) or into two child blocks (412), if fourth and fifth predetermined criteria are not fulfilled, and

suppressing the encoding the triple flag (519) if the fourth predetermined criterion is fulfilled wherein same is to be inferred to indicate that the predetermined block (41 1) of the picture (12) is to be split into two child blocks (412), if the fourth predetermined criterion is fulfilled, and

suppressing the encoding the triple flag (519) if the fifth predetermined criterion is fulfilled, wherein the triple flag (519) is to be inferred to indicate that the predetermined block (411) of the picture (12) is to be split into three child blocks (412), if the fifth predetermined criterion is fulfilled,

if the predetermined block (411) of the picture (12) is to be split,

resuming the encoding the splitting information (415) for the child blocks (412) using even further flags of the splitting information (415),

encoding the split direction flag (518) into the data stream (14) by context adaptive entropy encoding using a second context (552) which depends on whether, and discriminates between,

a first number of criteria among the fourth and fifth predetermined criteria which would be fulfilled in case of a split direction indicated by the split direction flag (518) being horizontal equals a second number of criteria among the fourth and fifth predetermined criteria which would be fulfilled in case of the split direction indicated by the split direction flag (518) being vertical,

the first number being greater than the second number, and

the first number being smaller than the second number.

100. Method for encoding a picture (12), comprising

partitioning the picture (12) into coding blocks (425) using recursive multi-tree splitting and encoding splitting information (415) defining the partitioning in a data stream (14),

encoding the picture (12) into coding information (440) which relates to the coding blocks (425) and encode the coding information (440) in the data stream (14),

wherein the method comprises encoding the splitting information (415) into the data stream (14) by

encoding a split flag (416) and a quad flag (417) of the splitting information (415) into the data stream (14), wherein the split flag (416) indicates whether a predetermined block (411) of the picture (12) is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block (411) becoming one of the coding blocks (425), and the quad flag (417) indicates whether the predetermined block (411) of the picture (12) is to be split into four child blocks (412) or not,

if the predetermined block (411) of the picture (12) is to be split, but not to be split into four child blocks (412),

encoding a split direction flag (518) into the data stream (14) which indicates whether the predetermined block (411) of the picture (12) is to be split vertically or horizontally, and

encoding a triple flag (519) into the data stream (14) which indicates whether the predetermined block (411) of the picture (12) is to be split into three child blocks (412) or into two child blocks (412),

if the predetermined block (411) of the. picture (12) is to be split,

resuming the encoding the splitting information (415) for the child blocks (412) using even further flags of the splitting information (415),

encoding the triple flag (519) into the data stream (14) by context adaptive entropy encod-ing using a third context (853) which

depends on

a number of splits of the recursive multi-tree splitting using which the predetermined block (41 1 ) is obtained, or

a size of the predetermined block (411), and/or

depends on whether, and discriminates between,

the split direction flag (518) indicating a horizontal split direction, and

the split direction flag (518) indicating a vertical split direction.

101. Method for encoding a picture (12), comprising

partitioning the picture (12) into coding blocks (425) using recursive multi-tree splitting and encode splitting information (415) defining the partitioning in a data stream (14),

encoding the picture (12) into coding information (440) which relates to the coding blocks (425) and encode the coding information (440) in the data stream (14),

wherein the method comprises encoding the splitting information (415) into the data stream (14) by

encoding a split flag (416) and a quad flag (417) of the splitting information (415) into the data stream (14), wherein the split flag (416) indicates whether a predetermined block (411) of the picture (12) is to be split or not to be split thereby stopping the recursive multi-tree splitting with the predetermined block (411) becoming one of the coding blocks (425), and the quad flag (417) indicates whether the predetermined block (411) of the picture (12) is to be split into four child blocks (412) or not,

if the predetermined block (411) of the picture (12) is to be split, but not to be split into four child blocks (412);

encoding one or more further flags (418) of the splitting information (415) into the data stream (14) which indicate whether the predetermined block (411) of the picture (12) is to be split into two or three child blocks (412) vertically or horizontally,

if the predetermined block (411) of the; picture (12) is to be split,

resuming the encoding the splitting information (415) for the child blocks (412) using even further flags of the splitting information (415),

wherein the method comprises selecting one of a first mode and a second mode, and,

in the first mode, encoding the quad flag (417) after the split flag (416) if the split flag (416) indicates that the predetermined block (411) of the picture (12) is to be split, and

in the second mode, encoding the split flag (416) after the quad flag (417) if the quad flag (417) indicates that the predetermined child block of the picture (12) is not to be split into four child blocks (412).

102. Data stream encoded by a method according to any one of claims 92 to 101.

103. Computer program having a program code for executing a method according to any one of claims 87 to 101 , when the program runs on one or several computers.