Transform Coefficient Block Coding Description
The present application is concerned with the coding of pictures and videos using trans¬form coefficient block coding.
In other words, the present application to the field of digital signal processing and, in par-ticular, to methods and devices for image and video decoders and encoders.
It is the object of the present invention to provide concepts for more efficiently coding a picture and/or a video a data stream.
This object is achieved by the subject-matter of the independent claims of the present application.
In accordance with a first aspect of the present application, a coding efficiency increase in picture coding is achieved by using a context or context model for entropy encod-ing/decoding a certain transform coefficient block of a certain color component which de-pends on the transform coefficient block of a different color component. That is, a block of a picture is separately subject to a transformation for a first color component and a second color component, respectively, so as to obtain a first transform coefficient block for the first color component and second transform coefficient block for the second color component, and an entropy encoding/decoding the second transform coefficient block context-adaptively, the context used is selected dependent on the first transform coefficient block. Both transformations might relate to a prediction residual determined for the block for each color component, but this is merely optional. In any case, rendering the context used for entropy encoding/decoding the second transform coefficient block dependent on the first transform coefficient block improves the probability estimation underlying the entropy encoding/decoding and, accordingly, increases the coding efficiency. In accordance with an embodiment, the context dependency on the first transform coefficient block is used, or applied for, an indication coded into the data stream for the first and second transform coefficient blocks, which indicates whether the transform coefficients within the respective transform coefficient block are encoded into the data stream, or whether the encoding of

the transform coefficients of the respective transform coefficient block is skipped and all transform coefficients within the respective transform coefficient block are zero. This indi-cation might be a flag signaled for both transform coefficient blocks in the data stream. Thus, in accordance with this embodiment, encoding/decoding of the indication for the second transform coefficient block is performed using context-adaptive entropy encod-ing/decoding using a context which depends on the first transform coefficient block such as depending on the indication signaled in the data stream for the first transform coeffi¬cient block or quantization levels of transform coefficients of the first transform coefficient block.
In accordance with a second aspect of the present application picture coding using trans-form coefficient block entropy coding is rendered more efficient by spending a separate set of contexts for entropy coding a quantization level of certain transform coefficients. In particular, a transform coefficient block which represents a block of the picture is assumed to be coded into the data stream using a scan pattern which sequentially traverses the transform coefficients of the transform coefficient block. Accordingly, encoding/decoding data representing a coding set of transform coefficients traversed by the scan pattern from a first termination coefficient position onwards in a predetermined direction to a second termination coefficient position is done using entropy encoding/decoding. The data com-prises quantization levels of the transform coefficients in the coded set of transform coeffi-cients. The encoding/decoding the quantization levels is done context-adaptively using a first set of contexts for the quantization level of the transform coefficient at the first termi-nation coefficient position or at the second termination coefficient position, wherein this first set of contexts is disjoined to a second set of contexts used for any other transform coefficient in the coded set of transform coefficients. For instance, a separate context set is used for the DC transform coefficient of the transform coefficient block or, differently, speaking, the transform coefficient at the upper left-hand side, with the predetermined direction leading to this DC transform coefficient which represents the second termination coefficient position, though. For instance, the transform coefficients' quantization levels may be coded using context-adaptive binary entropy coding/decoding by using a binariza-tion of the quantization levels of the transform coefficients and the disjoined set of con¬texts may apply to, or be used for, one or more bins of the binarization such as a prefix part of the binarization.
In accordance with a third aspect of the present application, a coding efficiency improve-ment in encoding a picture using entropy coding of a transform coefficient block is

achieved by determining a context for entropy encoding/decoding a quantization level of a currently encoded transform coefficient of the transform coefficient block based on a sum of and/or a number of significant ones among, one or more previously encoded transform coefficients located at positions determined by a local template positioned at the currently encoded/decoded transform coefficient. That is, a local template is used in order to exam-ine transform coefficients located nearby in the transform coefficient block as far as the quantization level of the one or more transform coefficients thus examined is revealed by a previous portion of the data stream. For instance, the entropy encoding/decoding of the quantization levels of the transform coefficients of the transform coefficient block may be done on a binary basis by sequentially entropy encoding/decoding bins of a binarization of the quantization levels of the transform coefficient in a plurality of passes and the context for at least bin of the binarization of the currently encoded/traversed transform coefficient may, thus, be determined based on the just-mentioned sum and/or the just-mentioned number of significant ones among the transform coefficients located at the local template. For instance, the sum may be a sum of an absolute value of the coefficient level of the one or more previous transform coefficients located at the local template, which absolute value this coefficient level of the one or more previous transform coefficients minimally has according to previously encoded/decoded bins of the binarization of the coefficient level of the one or more previous transform coefficients. Additionally or alternatively, the context may be determined based on the number of significant ones among the one or more previous transform coefficients located at the local template with the significance being determined based on the previously encoded/decoded bins.
A further aspect of the present application relates to coding transform coefficients of a transform coefficient block using binarization of absolute values of the quantization levels of the transform coefficients. In accordance with this aspect of the present application, a coding efficiency increase is achieved by setting a binarization parameter for parameteriz-ing the binarization of a currently encoded/decoded transform coefficient based on a sum of, and/or a number of significant ones among, one or more previously encoded/decoded transform coefficients located at positions determined by a local template positioned at the currently encoded/decoded transform coefficient. For instance, a first part of the binariza-tion of the transform coefficients might be coded using context-adaptive entropy encod-ing/decoding while a second part of the binarization is encoded/decoded using an equi-probability bypass mode. That is, the second part is written into the data stream, and read therefrom, at a code rate of one. The second part might comprise a prefix part and a suffix part and the binarization parameter may determine the length of the prefix part. The length

might, for instance, be an Exp-Golomb order or Rice parameter. Similar statements as made above might be true with respect to the possibility of coding the transform coeffi-cients of the transform coefficient block, or the coefficient levels thereof, in several passes and with respect to the consideration of this circumstance in forming this sum and/or de-termining the number of significant coefficients.
A further aspect of the present application also relates to the binarization used to code absolute values of quantization levels of the transform coefficients of a transform coeffi-cient block. In particular, in accordance with this aspect, picture coding is made more effi-cient by adaptively varying a cutoff value associated with a binarization. The binarization comprises a first binarization code below a cutoff value and a second binarization code, prefixed by a codeword of the first binarization code for the cutoff value, above the cutoff value. The adaptive variation of the cutoff value is performed dependent on previously encoded/decoded transform coefficients. For instance, the adaptation may be done in a manner also resulting in setting the cutoff value to zero whereupon the binarization merely comprises the second binarization code. The coding may be done in a manner so that bins of the first binarization code are coded context-adaptively, whereas bins of the sec¬ond binarization code are coded in bypass mode.
A further aspect of the present application also relates to the cutoff value and aims at in-creasing the coding efficiency by setting the cutoff value depending on one or more of a size of the block, a color component of the block, a prediction mode underlying a predic¬tion signal a prediction residual of which the block represents, a transformation underlying the transform coefficient block, a quantization parameter used to quantize the transform coefficient block, a measure of an energy of previously encoded/decoded transform coef-ficients, wherein the latter may be located at positions determined by a local template po-sitioned at a currently encoded/decoded transform coefficient or located at positions within a partition of the transform coefficient block offset to a current partition, the currently en-coded/decoded transform coefficient is located in and preceding the current partition ac-cording to a coding order used for encoding/decoding the absolute value of the quantiza¬tion level of the transform coefficients of the transform coefficient block defined by travers¬ing the transform coefficients of the transform coefficient block along a scan pattern in a predetermined direction.
An even further aspect of the present application aims at increasing the coding efficiency of picture coding using transform coefficient block coding by an intelligent way of setting

the shape of the local template or disabling the local template used for context-adaptively entropy encoding quantization levels of transform coefficients of the transform coefficient block. In particular, the dependency may involve one or more of a size of the block, a col¬or component of the block, a position of a termination coefficient position at which, when traversing the scan pattern along a forward direction, a last non-zero transform coefficient results, and a transformation underlying the transform coefficient block. The context may then be determined based on one or more previously encoded/decoded transform coeffi-cients located at positions determined by the local template positioned at the currently encoded/decoded transform coefficient or, if the local template is disabled, independent from these transform coefficients. In this manner, the context managing complexity, the number of context and the context efficiency in terms of probability estimation accuracy may be better determined, or adapted to, on the actual needs. In this regard, one should know that the usage of too many contexts does not increase the coding efficiency inevita-bly. Rather, the selection of contexts needs to take into account that contexts should be, preferably, used sufficiently frequently in order to, by way of context updates, attain good probability estimations. Thus, this aspect sees to adapt the context managing characteris¬tic to the needs in order to improve the coding efficiency.
In accordance with a further aspect of the present application, the transform coefficient block is partitioned into patterns for sake of using separate sets of contexts for the various partitions. A coding efficiency increase is aimed at by varying the partitions in shape, so that they are not conformed to each other within the transform coefficient block, and/or by shaping the partitions depending on a scanning pattern along which the entropy encod-ing/decoding the quantization levels of the transform coefficient block is performed, and/or by shaping the partitions depending on a size of the block and/or by shaping the partitions depending on an explicit partition shaping information. Again, the idea behind this aspect relates to the necessity to adapt the context management complexity to the actual needs. Thereby, the coding efficiency is increased.
A further aspect of the present application relates to the partitioning of a transform coeffi-cient block into partitions in terms of signaling in the data stream for each partition an indi-cation whether all transform coefficients within the respective partition are coded into the data stream or whether the coding of all transform coefficients within the respective parti¬tion is skipped and all transform coefficients within the respective partition are zero. In particular, in accordance with this aspect of the present application, the indication is inter¬preted in a way indicating whether all coefficients are coded or none. Each of these parti-

tions may have a set of contexts associated therewith using which the transform coeffi-cients within the respective partition are encoded if so indicated by the indication. In other words, here the partition wise indication of zeroness is indicative, if so set, that all trans¬form coefficients within a certain partition are coded and this circumstance needs not to be questioned anymore.
A further aspect of the present application also relates to an aspect of spending partition-specific context sets for encoding the quantization levels of transform coefficients within the various partitions and aims at improving the coding efficiency by signaling by way of a partition mode for the transform coefficient block in the data stream, whether partitioning is used, or whether such partitioning is disabled and this one set of context is used globally for the transform coefficient block instead.
Finally, a further aspect of the present application also deals with the partition-specific context set usage and suggests improving the coding efficiency by decoupling the scan pattern along which the transform coefficients of the transform coefficient block are se-quentially coded, from the partitioning in that the scan pattern sequentially traverses the transform coefficients of the transform coefficient block in a manner so that at least one transform coefficient of a first partition is traversed between two transform coefficients of a second partition. In this manner, it is feasible to traverse the transform coefficients in a manner so that the "knowledge increase" during scanning the transform coefficients in-creases more rapidly so as to gain improved coding history for the context selec-tion/adaptation, but with concurrently being able to appropriately associated individual context sets to various partitions of the transform block.
Advantageous implementations of the embodiments and aspects described above are the subject of dependent claims. Preferred embodiments of the present application are de-scribed below with respect to the figures among which:
Fig. 1 shows a schematic block diagram of a block-based predictive decoder us-
ing transform-based residual coding, which serves as an example for pos-sible implementations of the embodiments of the present application de-scribed herein;

Fig. 2 shows a schematic block diagram of a block-based predictive video decod-
er fitting to the encoder of Fig. 1, which serves as an example for possible implementations of the embodiments for a decoder described herein;
Fig. 3 shows an example for a partitioning of a picture into coding blocks encoded
using intra-prediction and inter-prediction, respectively, and a partition of the same picture into residual blocks for the sake of transform-based resid¬ual coding of the prediction residual with concurrently schematically illus¬trating the prediction correction on the basis of the residual by way of addi¬tion of the prediction signal and the residual signal, respectively;
Fig. 4 shows a schematic diagram illustrating the transform-based residual coding
of a residual block by de-encoding the transform coefficient block 92 asso-ciated with the residual block via a certain transformation;
Fig. 5 shows a schematic diagram illustrating the coding of a coded set of trans-
form coefficients of a transform coefficient block by defining the coded set via an indication indicating a last non-zero transform coefficient when scan-ning the transform coefficients from a specific firstly scanned transform co-efficient such as a DC coefficient to a coefficient farthest away from this first coefficient, so that the coded set comprises all coefficients between the last non-zero coefficient and the transform coefficient at the first coefficient po¬sition;
Fig. 6 shows a schematic diagram illustrating the possibility of coding transform
coefficients using a binarization composed of a first binarization code and a second binarization code with switching from the binarization merely com-prising the first binarization code to a state where the binarization compris¬es the codeword of the first binarization code for the cutoff value followed by the second binarization code;
Fig. 7 shows a schematic diagram illustrating a possibility for having a binarization
with a prefix part and a suffix part when such a binarization may underlie, for instance, the second binarization code of Fig. 6;

Fig. 8 exemplarily illustrates a partitioning of a transform coefficient block into
partitions, here a regular partitioning into rows and columns of partitions, each partition, accordingly, being composed of an array of coefficients, wherein the partitioning may be used for a context set association to the transform coefficients and/or zeroness indication of the transform coeffi-cients as described herein below;
Fig. 9 shows a schematic diagram illustrating the usage of partitions for the sake
of context set association;
Fig. 10 shows schematically a transform coefficient block and the usage of a local
template for a currently encoded/decoded transform coefficient block for the sake of selecting one context for this currently entropy-encoded/decoded transform coefficient;
Fig. 11a shows a schematic diagram illustrating the coding of a residual block with
respect to a decomposition of this block into more than one color compo-nent;
Fig. 11b schematically illustrates the data 96 of coding the transform coefficient
block 92 into a data stream 14 as including a global zeroness indication 190 indicating whether all transform coefficients of that block 92 are zero, in which case the quantization levels of the transformation coefficients may not have to be coded but infer to be zero at the decoder side;
Fig. 11c schematically illustrates the usage of partitioning of a transform coefficient
block into partitions for the sake of indicating, in units of partitions, the zeroness of transform coefficients by way of coded sub-block flags CBFs;
Fig. 11 d illustrates that the data 96 into which a transform coefficient block is coded
may comprise a last position indication 114 indicating the last coefficient position of a non-zero transform coefficient as shown in Fig. 5;
Fig. 11 e exemplarily shows the entropy de/encoding of quantization levels of trans-
form coefficients in a context-adaptive manner using a certain context out of a context set;

Fig. 11 f schematically illustrates the fact that the data into which a transform coeffi-
cient block is coded may comprise a sequential coding of the transform co-efficients' quantization levels in a coding order 102 in the data stream which corresponds to traversing the scan part of Fig. 5 from the last coefficient position to the first coefficient position;
Fig. 12 shows a schematic diagram illustrating a first embodiment of the present
application of performing context selection for one color component de-pendent on the transform coefficient block of the same residual block for another color component;
Fig. 13 shows a schematic diagram illustrating a partitioning of a transform coeffi-
cient block into partitions which do not coincide in shape as shown in Fig. 8;
Fig. 14 shows a schematic diagram illustrating a possibility of varying shapes of a
local template used for context selection as taught in Fig. 10, or even disa-bling same;
Fig. 15 shows a schematic diagram illustrating a transform coefficient block parti-
tioned into partitions with the scan part for sequentially encoding the trans-form coefficients traversing the transform coefficients in a manner so that transform coefficients of the partitions are interleaved with each other.
Fig. 16 shows a schematic diagram illustrating a transform coefficient block and its
coding using an interleaving scan part as shown in Fig. 15 with exemplarily illustrating a currently entropy-encoded/decoded transform coefficient and previously encoded transform coefficients exceeding certain thresholds, with a count thereof being used, for example, for context selection for the currently entropy-encoded/decoded transform coefficient;
Fig. 17 shows a schematic diagram illustrating a coding sequence of the quantiza-
tion level of coefficients on the one hand and zeroness indications of coded sub-block flags on the other hand, resulting from coding a transform coeffi-cient block with an interleaving scan part exemplarily shown in Fig. 18;

Fig. 18 also shows a transform coefficient block with a scan part which interleaves
transform coefficients of different partitions as shown in Figs. 15 and 16, with illustrating using hatching of the non-zero coefficients;
Fig. 19 illustrates a partition-wise scanning example of transform examples of a
transform coefficient block;
Fig. 20 illustrates a pseudocode for coding a transform coefficient block;
Fig. 21 illustrates a pseudocode for binarizing an absolute value of a quantization
level of a transform coefficient;
Fig. 22 illustrates an example for binarizing an absolute value of a quantization
level of a transform coefficient;
Fig. 23 illustrates a pseudocode for coding transform coefficients of a transform
coefficient block;
Fig. 24 illustrates a pseudocode for coding transform coefficients of a transform
coefficient block; and
Fig. 25 illustrates different examples for a partitioning of a transform coefficient
block into partitions.
The following description of the figures starts with a presentation of a description of video encoder and video decoder of a block-based predictive codec for coding pictures of a vid¬eo in order to form an example for a coding framework into which embodiments described herein may be built. The video encoder and video decoder are described with respect to Figs 1 to 3. Thereinafter the description of further embodiments of the present application are presented with respect to figures. Same are numbered and in the above section a reference is made which portions above refer to which embodiment described and claimed below. All these embodiments could be built into the video encoder and decoder of Figs. 1 and 2, respectively, although the embodiments described herein such as those described with respect to the subsequent Figs, may also be used to form video encoder and video decoders not operating according to the coding framework underlying the video encoder and video decoder of Figs. 1 and 2.

Fig. 1 shows an apparatus for predictively coding a video 11 composed of a sequence of pictures 12 into a data stream 14. Block-wise predictive coding is used to this end. Fur¬ther, transform-based residual coding is exemplarily used. The apparatus, or encoder, is indicated using reference sign 10. Fig. 2 shows a corresponding decoder 20, i.e. an appa-ratus 20 configured to predictively decode the video 11' composed of pictures 12' in pic¬ture blocks from the data stream 14, also here exemplarily using transform-based residual decoding, wherein the apostrophe has been used to indicate that the pictures 12' and vid¬eo 11', respectively, as reconstructed by decoder 20 deviate from pictures 12 originally encoded by apparatus 10 in terms of coding loss introduced by a quantization of the pre-diction residual signal. Fig. 1 and Fig. 2 exemplarily use transform based prediction resid¬ual coding, although embodiments of the present application are not restricted to this kind of prediction residual coding. This is true for other details described with respect to Fig. 1 and 2, too, as will be outlined hereinafter.
The encoder 10 is configured to subject the prediction residual signal to spatial-to-spectral transformation and to encode the prediction residual signal, thus obtained, into the data stream 14. Likewise, the decoder 20 is configured to decode the prediction residual signal from the data stream 14 and subject the prediction residual signal thus obtained to spec¬tral-to-spatial transformation.
Internally, the encoder 10 may comprise a prediction residual signal former 22 which gen-erates a prediction residual 24 so as to measure a deviation of a prediction signal 26 from the original signal, i.e. video 11 or a current picture 12. The prediction residual signal for¬mer 22 may, for instance, be a subtracter which subtracts the prediction signal from the original signal, i.e. current picture 12. The encoder 10 then further comprises a transform¬er 28 which subjects the prediction residual signal 24 to a spatial-to-spectral transfor¬mation to obtain a spectral-domain prediction residual signal 24' which is then subject to quantization by a quantizer 32, also comprised by encoder 10. The thus quantized predic¬tion residual signal 24" is coded into bitstream 14. To this end, encoder 10 may optionally comprise an entropy coder 34 which entropy codes the prediction residual signal as trans¬formed and quantized into data stream 14. The prediction residual 26 is generated by a prediction stage 36 of encoder 10 on the basis of the prediction residual signal 24" de¬coded into, and decodable from, data stream 14. To this end, the prediction stage 36 may internally, as is shown in Fig. 1, comprise a dequantizer 38 which dequantizes prediction residual signal 24" so as to gain spectral-domain prediction residual signal 24'", which

corresponds to signal 24' except for quantization loss, followed by an inverse transformer 40 which subjects the latter prediction residual signal 24'" to an inverse transformation, i.e. a spectral-to-spatial transformation, to obtain prediction residual signal 24"", which corresponds to the original prediction residual signal 24 except for quantization loss. A combiner 42 of the prediction stage 36 then recombines, such as by addition, the predic¬tion signal 26 and the prediction residual signal 24"" so as to obtain a reconstructed signal 46, i.e. a reconstruction of the original signal 12. Reconstructed signal 46 may correspond to signal 12'.
A prediction module 44 of prediction stage 36 then generates the prediction signal 26 on the basis of signal 46 by using, for instance, spatial prediction, i.e. intra prediction, and/or temporal prediction, i.e. inter prediction. Details in this regard are described in the follow¬ing.
Likewise, decoder 20 may be internally composed of components corresponding to, and interconnected in a manner corresponding to, prediction stage 36. In particular, entropy decoder 50 of decoder 20 may entropy decode the quantized spectral-domain prediction residual signal 24" from the data stream, whereupon dequantizer 52, inverse transformer 54, combiner 56 and prediction module 58, interconnected and cooperating in the manner described above with respect to the modules of prediction stage 36, recover the recon-structed signal on the basis of prediction residual signal 24" so that, as shown in Fig. 2, the output of combiner 56 results in the reconstructed signal, namely the video 11'or a current picture 12' thereof.
Although not specifically described above, it is readily clear that the encoder 10 may set some coding parameters including, for instance, prediction modes, motion parameters and the like, according to some optimization scheme such as, for instance, in a manner optimizing some rate and distortion related criterion, i.e. coding cost, and/or using some rate control. As described in more details below, encoder 10 and decoder 20 and the cor-responding modules 44, 58, respectively, support different prediction modes such as intra-coding modes and inter-coding modes or modes where the former modes form a kind of set or pool of primitive prediction modes based on which the predictions of picture blocks are composed. The granularity at which encoder and decoder switch between these pre-diction compositions may correspond to a subdivision of the pictures 12 and 12', respec-tively, into blocks. Note that some of these blocks may be blocks being solely intra-coded and some blocks may be blocks solely being inter-coded and, optionally, even further

Claims
1. Encoder for encoding a picture into a data stream, configured to
subject a block of the picture separately for a first color component and a second color component to a transformation to obtain a first transform coefficient block and a second transform coefficient block, respectively,
entropy encode the second transform coefficient block context-adaptively using a context which depends on the first transform coefficient block.
2. Encoder of claim 1, configured to
encode for each partition of a set of partitions (120) into which the second trans¬form coefficient block (922) is subdivided an indication (150) whether the transform coefficients within the respective partition are encoded into the data stream, or whether the encoding of the transform coefficients within the respective partition is skipped and all transform coefficients within the respective partition are zero, and
entropy encode quantization levels of the transform coefficients of the second transform coefficient block (922) for partitions for which the indication indicates that the transform coefficients within the respective partition are encoded into the data stream and skip the encoding of the transform coefficients within the partitions for which the indication indicates that the encoding of the transform coefficients within the respective partition is skipped and all transform coefficients within the partitions are zero,
wherein the encoding of the indication is performed using context-adaptive entropy coding using a context which depends on the first transform coefficient block (921).
3. Encoder of claim 2, configured to
encode for each further partition of a set of further partitions into which the first transform coefficient block (921) is subdivided a further indication (150) indicating whether the transform coefficients within the respective further partition (120) are encoded into the data stream, or whether the encoding of the transform coeffi-

cients within the respective further partition is skipped and all transform coefficients within the respective further partition are zero, and
entropy encode quantization levels of the transform coefficients of the first trans-form coefficient block (921) for further partitions for which the further indication indi-cates that the transform coefficients within the respective further partition are en-coded into the data stream and skip the encoding of the transform coefficients within the further partitions for which the further indication indicates that the encod-ing of the transform coefficients within the respective further partition is skipped and all transform coefficients within the further partitions are zero,
wherein the encoding of the indication for the second transform coefficient block (922) is performed using context-adaptive entropy coding using a context which depends on the further indication of the further partitions of the first transform coef-ficient block (921) and/or the quantization levels of the transform coefficients of the first transform coefficient block (921).
4. Encoder of claim 1, configured to
encode an indication (190) whether the transform coefficients within the second transform coefficient block (922) are encoded into the data stream, or whether the encoding of the transform coefficients within the second transform coefficient block (922) is skipped and all transform coefficients within the second transform coeffi-cient block (922) are zero, and
entropy encoding quantization levels of the transform coefficients of the second transform coefficient block (922) if the indication indicates that the transform coeffi-cients of the second transform coefficient block (922) are encoded into the data stream and skip the encoding of the transform coefficients of the second transform coefficient block (922) if the indication indicates that the encoding of the transform coefficients of the second transform coefficient block (922) is skipped and all trans-form coefficients of the second transform coefficient block (922) are zero,
wherein the encoding of the indication (190) is performed using context-adaptive entropy coding using a context which depends on the first transform coefficient block (921).
5. Encoder of claim 4 configured to

encoding a further indication (190) whether the transform coefficients of the first transform coefficient block (921) are encoded into the data stream, or whether the encoding of the transform coefficients of the first transform coefficient block (921) is skipped and ail transform coefficients of the first transform coefficient block (921) are zero, and
entropy encoding quantization levels of the transform coefficients of the first trans-form coefficient block (921) if the further indication indicates that the transform co-efficients of the first transform coefficient block (921) are encoded into the data stream and skip the encoding of the transform coefficients of the first transform co-efficient block (921) if the further indication indicates that the encoding of the trans-form coefficients of the first transform coefficient block (921) is skipped and all transform coefficients of the first transform coefficient block (921) are zero,
wherein the encoding of the indication (190) for the second transform coefficient block is performed using context-adaptive entropy coding using a context which depends on the further indication for the first transform coefficient block (921) and/or the quantization levels of the transform coefficients of the first transform co¬efficient block (921).
6. Encoder of claim 5, configured to
in the encoding of the indication (190) for the second transform coefficient block, select a first context if the further indication indicates that the transform coefficients of the first transform coefficient block are encoded into the data stream, or a sec¬ond context if the further indication indicates that the encoding of the transform co-efficients of the first transform coefficient block is skipped and all transform coeffi-cients within the respective further partition are zero.
7. Encoder of any of claims 1 to 6, configured to
encode into the data stream a first indication (114) of a first termination coefficient position at which, when traversing a first scan pattern which sequentially traverses transform coefficients of the first transform coefficient block along a forward direc-tion, a first last non-zero transform coefficient resides,

encode into the data stream first data representing a first coded set of transform coefficients of the first transform coefficient block (921) traversed by the first scan pattern from the first termination coefficient position in reverse direction, the first data comprising quantization levels of transform coefficients in the first coded set of transform coefficients,
encode into the data stream a second indication (114) of a second termination co-efficient position at which, when traversing a second scan pattern which sequen¬tially traverses transform coefficients of the second transform coefficient block along a forward direction, a second last non-zero transform coefficient resides,
encode into the data stream second data representing a second coded set of transform coefficients of the second transform coefficient block (922) traversed by the second scan pattern from the second termination coefficient position in reverse direction, the second data comprising quantization levels of transform coefficients in the second coded set of transform coefficients,
wherein the encoding of the second indication of the second transform coefficient block (922) is performed using context-adaptive entropy coding using a context which depends on the first termination coefficient position.
8 Encoder of any of claims 1 to 7, configured to
encode the quantization levels of a predetermined transform coefficient of the sec-ond transform coefficient block by using a binarization code and entropy encoding a first bin of the binarization code using a context which depends on the first bin of the binarization code of a co-located transform coefficient of the first transform co-efficient block.
9. Encoder of any of claims 1 to 8, wherein the first and second color components are chroma components.
10. Decoder for decoding a picture from a data stream, configured to
derive a block (84) of the picture by, separately for a first color component and a second color component, a reverse transformation of a first transform coefficient block (92i) and a second transform block (922), respectively,

entropy decode the second transform coefficient block (922) context-adaptively us-ing a context which depends on the first transform coefficient block.
11. Decoder of claim 10, configured to
decoding for each partition of a set of partitions (120) into which the second trans-form coefficient block (922) is subdivided an indication (150) indicating whether the transform coefficients within the respective partition are encoded into the data stream, or whether the encoding of the transform coefficients (91) within the re-spective partition is skipped and all transform coefficients within the respective par-tition are zero, and
entropy decoding quantization levels of the transform coefficients (91) of the sec-ond transform coefficient block for partitions for which the indication indicates that the transform coefficients within the respective partition are encoded into the data stream and skip the decoding of the transform coefficients within the partitions for which the indication indicates that the encoding of the transform coefficients within the respective partition is skipped and all transform coefficients within the partitions are zero,
wherein the decoding of the indication is performed using context-adaptive entropy decoding using a context (150) which depends on the first transform coefficient block (92^.
12. Decoder of claim 11, configured to
decoding for each further partition of a set of further partitions into which the first transform coefficient block (921) is subdivided a further indication (150) indicating whether the transform coefficients within the respective further partition (120) are encoded into the data stream, or whether the encoding of the transform coeffi¬cients within the respective further partition is skipped and all transform coefficients within the respective further partition are zero, and
entropy decoding quantization levels of the transform coefficients (91) of the first transform coefficient block (921) for further partitions for which the further indication indicates that the transform coefficients within the respective further partition are encoded into the data stream and skip the decoding of the transform coefficients

within the further partitions for which the further indication indicates that the encod-ing of the transform coefficients within the respective further partition is skipped and all transform coefficients within the further partitions are zero,
wherein the decoding of the indication for the second transform coefficient block (922) is performed using context-adaptive entropy decoding using a context which depends on the further indication of the further partitions of the first transform coef-ficient block (921) and/or the quantization levels of the transform coefficients of the first transform coefficient block (921).
13. Decoder of claim 10, configured to
decoding an indication (190) indicating whether the transform coefficients within the second transform coefficient block (922) are encoded into the data stream, or whether the encoding of the transform coefficients within the second transform co-efficient block (922) is skipped and all transform coefficients within the second transform coefficient block (922) are zero, and
entropy decoding quantization levels of the transform coefficients of the second transform coefficient block (922) if the indication indicates that the transform coeffi-cients of the second transform coefficient block (922) are encoded into the data stream and skip the decoding of the transform coefficients of the second transform coefficient block (921) if the indication indicates that the encoding of the transform coefficients of the second transform coefficient block (921) is skipped and all trans-form coefficients of the second transform coefficient block (922) are zero,
wherein the decoding of the indication (190) is performed using context-adaptive entropy decoding using a context which depends on the first transform coefficient block (921).
14. Decoder of claim 13 configured to
decoding a further indication (190) indicating whether the transform coefficients of the first transform coefficient block (921) are encoded into the data stream, or whether the encoding of the transform coefficients of the first transform coefficient block (921) is skipped and all transform coefficients within the respective first trans-form coefficient block (921) are zero, and

entropy decoding quantization levels of the transform coefficients of the first trans-form coefficient block (921) if the further indication indicates that the transform co-efficients of the first transform coefficient block (921) are encoded into the data stream and skip the decoding of the transform coefficients of the first transform co-efficient block (921) if the further indication indicates that the encoding of the trans-form coefficients of the first transform coefficient block (921) is skipped and all transform coefficients of the first transform coefficient block (921) are zero,
wherein the decoding of the indication (190) for the second transform coefficient block (922) is performed using context-adaptive entropy decoding using a context which depends on the further indication for the first transform coefficient block (921) and/or the quantization levels of the transform coefficients of the first transform co-efficient block (921).
15. Decoder of claim 14, configured to
in the decoding of the indication (190) for the second transform coefficient block, select a first context if the further indication indicates that the transform coefficients of the first transform coefficient block are encoded into the data stream, or a sec-ond context if the further indication indicates that the encoding of the transform co-efficients of the first transform coefficient block is skipped and all transform coeffi-cients within the respective further partition are zero.
16. Decoder of any of claims 10 to 14, configured to
decode from the data stream a first indication (114) of a first termination coefficient position (98) at which, when traversing a first scan pattern (94) which sequentially traverses transform coefficients of the first transform coefficient block (921) along a forward direction, a first last non-zero transform coefficient resides,
decode from the data stream first data (96) representing a first coded set of trans-form coefficients of the first transform coefficient block (92i) traversed by the first scan pattern (94) from the first termination coefficient position (98) in reverse direc-tion, the first data comprising quantization levels of transform coefficients in the first coded set of transform coefficients,
decode from the data stream a second indication (114) of a second termination coefficient position (98) at which, when traversing a second scan pattern (94)

which sequentially traverses transform coefficients of the second transform coeffi-cient block (922) along a forward direction, a second last non-zero transform coeffi-cient resides,
decode from the data stream second data representing a second coded set of transform coefficients of the second transform coefficient block (922) traversed by the second scan pattern from the second termination coefficient position in reverse direction, the second data comprising quantization levels of transform coefficients in the second coded set of transform coefficients,
wherein the decoding of the second indication of the second transform coefficient block (922) is performed using context-adaptive entropy decoding using a context which depends on the first termination coefficient position.
17. Decoder of any of claims 10 to 16, configured to
decode quantization levels of a predetermined transform coefficient (130) of the second transform coefficient block (922) by using a binarization code (160) and en-tropy decoding a first bin of the binarization code using a context which depends on the first bin of the binarization code of a co-located transform coefficient of the first transform coefficient block (921).
18. Decoder of any of claims 10 to 16, wherein the first and second color components
are chroma components.

19. Encoder for encoding a picture (12) into a data stream (14), configured to
encode (108) a transform coefficient block (92) representing a block (84) of the pic-ture (12) into the data stream (14) using a scan pattern (94) which sequentially traverses transform coefficients of the transform coefficient block (92) by
encoding into the data stream (14) data (96) representing a coded set (100 shown hatched) of transform coefficients (91) traversed by the scan pattern (94) [or scan path] from a first termination coefficient position (98) in a pre-determined direction (102) to a second termination coefficient (104), the da¬ta (96) comprising quantization levels (108) of the transform coefficients in the coded set (100) of transform coefficients,
wherein the encoder is configured to entropy encode the quantization levels (106) context-adaptively using a first set (110) of contexts (112) for the quantization level of the transform coefficient at the first termination coefficient position (98) or at the second termination coefficient position (104) which is disjoint to a second set (110) of contexts (112) used for any other transform coefficient in the coded set (100) of transform coefficients.
20. Encoder according to claim 19, configured to
encode into the data stream (14) an indication (114) of a termination coeffi-cient position at which a, when traversing the scan pattern (94) along a for-ward direction (116), last non-zero transform coefficient resides, wherein the predetermined direction (102) is a reverse direction (118) and the first termination coefficient position is the termination coefficient position indi-cated by the indication (114) and the second termination coefficient position (104) is a coefficient position which is in the reverse direction (118) trav¬ersed latest along the scan pattern (94).
21. Encoder according to claim 20, configured to
use the first set of contexts for the transform coefficient at the first termina-tion coefficient position (98).

22. Encoder according to claim 21, wherein
the first set of contexts is disjoint to the second set (110) of contexts (112) used for any other transform coefficient in the coded set (100) of transform coefficients including the transform coefficient at the second termination coefficient position.
23. Encoder according to claim 20, configured to
use the first set of contexts for the transform coefficient at the second ter-mination coefficient position.
24. Encoder according to claim 23, wherein
the first set of contexts is disjoint to the second set (110) of contexts (112) used for any other transform coefficient in the coded set (100) of transform coefficients including the transform coefficient at the first termination coeffi-cient position.
25. Encoder according to claim 20, configured to
use the first set of contexts for the transform coefficient at the first termina-tion coefficient position (98), and
use a third set of contexts, disjoint from the first set, for the transform coef-ficient at the second termination coefficient position (98),
wherein the first and third sets are disjoint from the second sets of contexts used for any transform coefficient in the coded set of transform coefficients lying, along the scan pattern, between the first and second termination co-efficient positions.
26. Encoder according to any of claims 20 to 25,
wherein the first set is disjoint from the second set of contexts used for the transform coefficients at coefficient positions which are in the reverse direc-tion (118) traversed along the scan pattern (94) immediately after the first

termination coefficient position (98) and immediately before the second termination coefficient position (104).
27. Encoder according to any of claims 20 to 26, wherein the second termination coef¬
ficient position (104) is a DC coefficient position.
28. Encoder according to any of claims 19, wherein the disjointness is independent
from the first termination coefficient position (98).
329 Encoder according to claim 19 or 28, configured to
In entropy encoding (116) the quantization levels of the other transform coefficients of the transform coefficient block (92) context-adaptively, use, for each partition (sub-block) of partitions (120) into which the transform coefficient block (92) is subdivided, a set of contexts which is disjoint to the first set.
30. Encoder of claim 29, wherein the partitions (120) into which the transform coeffi¬
cient block is subdivided,
extend diagonally along a direction obliquely to a transform coefficient block's (92) diagonal (122) running through the second termination coefficient position (e.g. DC position).
31. Encoder of any of claims 19 to 30, configured to
binarize the quantization levels (106) to obtain a binarization of the quantization levels of the transform coefficients and use the first set (110) of contexts (112) and the second set (110) of contexts (112) for at least one bin of the binarization.
32. Encoder of any of claims 19 to 30, configured to
binarize the quantization levels (106) to obtain a binarization of the quantization levels of the transform coefficients and use the first set (110) of contexts (112) and the second set (110) of contexts (112) for at least one bin of a prefix part of the bi-narization.
33. Encoder of any of claims 19 to 32, wherein configured to,

select a first actually used context out of the first set (110) of contexts (112) for the quantization level of the transform coefficient at the first termination coefficient po-sition (98) or at the second termination coefficient position (104) and a second ac-tually used context out of the second set (110) of contexts (112) for the other trans-form coefficients in the coded set (100) of transform coefficients using previously encoded coefficients position at positions determined by a local template (132).
34. Decoder for decoding a picture (12) from a data stream (14), configured to
decode (108) a transform coefficient block (92) representing a block (84) of the pic-ture (12) from the data stream (14) using a scan pattern (94) which sequentially traverses transform coefficients (91) of the transform coefficient block (92) by
decoding from the data stream (14) data (96) representing a coded set (100) of transform coefficients (91) traversed by the scan pattern (94) from a first termination coefficient position (98) in a predetermined direction (102) to a second termination coefficient position (104), the data (96) com¬prising quantization levels (106) of the transform coefficients in the coded set (100) of transform coefficients,
wherein the decoder is configured to entropy decode the quantization levels (106) context-adaptively using a first set (110) of contexts (112) for the quantization level of the transform coefficient at the first termination coefficient position (98) or at the second termination coefficient position (104) which is disjoint to a second set (110) of contexts (112) used for any other transform coefficient in the coded set (100) of transform coefficients.
35. Decoder according to claim 34, configured to
decode from the data stream (14) an indication (114) of a termination coef-ficient position at which a, when traversing the scan pattern (94) along a forward direction (116), last non-zero transform coefficient resides, wherein the predetermined direction (102) is a reverse direction (118) and the first termination coefficient position is the termination coefficient position indi-cated by the indication (114) and the second termination coefficient position (104) is a coefficient position which is in the reverse direction (118) trav¬ersed latest along the scan pattern (94).

36. Decoder according to claim 35, configured to
use the first set of contexts for the transform coefficient at the first termina-tion coefficient position (98).
37. Decoder according to claim 36, wherein
the first set of contexts is disjoint to the second set (110) of contexts (112) used for any other transform coefficient in the coded set (100) of transform coefficients including the transform coefficient at the second termination coefficient position.
38. Decoder according to claim 35, configured to
use the first set of contexts for the transform coefficient at the second ter-mination coefficient position.
39. Decoder according to claim 38, wherein
the first set of contexts is disjoint to the second set (110) of contexts (112) used for any other transform coefficient in the coded set (100) of transform coefficients including the transform coefficient at the first termination coeffi-cient position.
40. Decoder according to claim 35, configured to
use the first set of contexts for the transform coefficient at the first termina-tion coefficient position (98), and
use a third set of contexts, disjoint from the first set, for the transform coef-ficient at the second termination coefficient position (98),
wherein the first and third sets are disjoint from the second sets of contexts used for any transform coefficient in the coded set of transform coefficients lying, along the scan pattern, between the first and second termination co-efficient positions.
41. Decoder according to any of claims 35 to 40, configured to

wherein the first set is disjoint from the second sets of contexts used for the transform coefficients at coefficient positions which are in the reverse direc-tion (118) traversed along the scan pattern (94) immediately after the first termination coefficient position (98) and immediately before the second termination coefficient position (104).
42 Decoder according to any of claims 35 to 41, wherein the second termination coef-ficient position (104) is a DC coefficient position.
43. Decoder according to any of claims 34, wherein the disjointness is independent from the first termination coefficient position (98).
44. Decoder according to claim 34 or 43, configured to
In entropy decoding (116) the quantization levels of the other transform coefficients of the transform coefficient block (92) context-adaptively, use, for each partition of partitions (120) into which the transform coefficient block (92) is subdivided, a set (110) of contexts which is disjoint to the first set.
45. Decoder of claim 44, wherein the partitions (120) into which the transform coeffi¬
cient block is subdivided,
extend diagonally along a direction obliquely to a transform coefficient block's (92) diagonal (122) running through the second termination coefficient position (104).
46. Decoder of any of claims 34 to 45, configured to
decode the quantization levels (106) in a manner binarized according to a binariza-tion of the quantization levels of the transform coefficients and use the first set (110) of contexts (112) and the second set (110) of contexts (112) for at least one bin of the binarization.
47. Decoder of any of claims 34 to45, configured to
decode the quantization levels (106) in a manner binarized according to a binariza-tion of the quantization levels of the transform coefficients and use the first set

(110) of contexts (112) and the second set (110) of contexts (112) for at least one bin of a prefix part (160) of the binarization (161).
48. Decoder of any of claims 34 to 47, wherein configured to,
select a first actually used context out of the first set (110) of contexts (112) for the quantization level of the transform coefficient at the first termination coefficient po-sition (98) or at the second termination coefficient position (104) and a second ac-tually used context out of the second set (110) of contexts (112) for the other trans-form coefficients in the coded set (100) of transform coefficients using previously decoded coefficients position at positions determined by a local template (132).

49. Encoder for encoding a picture into a data stream, configured to
entropy encode a quantization level of a currently encoded transform coefficient of a transform coefficient block (92) representing a block (84) of the picture (12) con-text-adaptively by
use of a context which is determined based on
a sum of, and/or
a number of significant ones among,
one or more previously encoded transform coefficients located at positions determined by a local template (132) positioned at the currently encoded transform coefficient.
50. Encoder of claim 49, configured to
determine the context by forming a difference between a first value determined based on the sum and a second value determined based on the number of significant transform coefficient levels among the one or more previously encoded transform coeffi-cients located at the positions determined by the local template.
51. Encoder of claim 49 or 50, configured to
entropy encoding the quantization level using context-adaptive binary arithmetic coding of a binarization of an absolute value of the quantization level involving a unary code, wherein the context is used for bins of the unary code.
52. Encoder of claim 49 or 50, configured to
entropy encode the quantization level using context-adaptive binary arithmetic cod-ing of a binarization of an absolute value of the quantization level involving a prefix part and a suffix part, wherein the context is used for one or more bins of the prefix part.
53. Encoder of any of claims 49 to 52, configured to

entropy encode bins of a binarization for quantization levels of transform coeffi-cients of the transform coefficient block (92) sequentially in a plurality of passes,
use the context for at least one bin of the binarization of the currently encoded transform coefficient, and
determine the context based on
a sum of an absolute value of coefficient level of the one or more previously encoded transform coefficients located at the positions determined by the local template (132) positioned at the currently encoded transform coeffi-cient, which absolute value the coefficient level of the one or more previ-ously encoded transform coefficients minimally has according to previously encoded bins of the binarization of the absolute value of the coefficient lev¬el of the one or more previously encoded transform coefficients.
54. Encoder of any of claims 49 to 53, configured to
entropy encode bins of a binarization for quantization levels of transform coeffi-cients of the transform coefficient block (92) sequentially in a plurality of passes,
use the context for at least one bin of the binarization of the currently encoded transform coefficient, and
determine the context based on
the number of significant ones among the one or more previously encoded transform coefficients located at the positions determined by the local tem-plate (132) positioned at the currently encoded transform coefficient.
55. Decoder for decoding a picture from a data stream, configured to
entropy decode a quantization level (106) of a currently decoded transform coeffi-cient (130) of a transform coefficient block (92) representing a block (84) of the pic-ture (12) context-adaptively by
use of a context which is determined based on

a sum of, and/or
a number of significant ones among,
one or more previously decoded transform coefficients located at positions determined by a local template (132) positioned at the currently decoded transform coefficient.
56. Decoder of claim 55, configured to
determine the context by forming a difference between a first value determined based on the sum and a second value determined based on the number of significant transform coefficient levels among the one or more previously decoded transform coeffi-cients located at the positions determined by the local template.
57. Decoder of claim 55 or 56, configured to
entropy decoding the quantization level using context-adaptive binary arithmetic decoding of a binarization of an absolute value of the quantization level involving a unary code (160), wherein the context is used for bins of the unary code.
58. Decoder of claim 55 or 56, configured to
entropy decode the quantization level using context-adaptive binary arithmetic de-coding of a binarization of an absolute value of the quantization level involving a prefix part (160) and a suffix part (162), wherein the context is used for one or more bins of the prefix part.
59. Decoder of any of claims 55 to 58, configured to
entropy decode bins of a binarization for quantization levels of transform coeffi-cients of the transform coefficient block (92) sequentially in a plurality of passes,
use the context for at least one bin of the binarization of the currently decoded transform coefficient (130), and
determine the context based on

a sum of an absolute value of coefficient level of the one or more previously decoded transform coefficients located at the positions determined by the local template (132) positioned at the currently decoded transform coeffi-cient, which absolute value the coefficient level of the one or more previ-ously decoded transform coefficients minimally has according to previously decoded bins of the binarization (161) of the absolute value of the coeffi¬cient level of the one or more previously decoded transform coefficients.
60. Decoder of any of claims 55 to 59, configured to
entropy decode bins of a binarization for quantization levels of transform coeffi-cients of the transform coefficient block (92) sequentially in a plurality of passes,
use the context for at least one bin of the binarization of the currently decoded transform coefficient (130), and
determine the context based on
the number of significant ones among the one or more previously decoded transform coefficients located at the positions determined by the local tem-plate (132) positioned at the currently decoded transform coefficient.

61. Encoder for encoding a picture into a data stream, configured to
encode a transform coefficient block (92) representing a block (84) of the picture (12) into the data stream by
encoding an absolute value of a quantization level of a currently encoded transform coefficient of the transform coefficient block in a manner bina-rized using a binarization (161) which is parameterized using a binarization parameter (163),
setting of the binarization parameter based on
a sum of, and/or
a number of significant ones among,
one or more previously encoded transform coefficients located at positions determined by a local template (132) positioned at the currently encoded transform coefficient.
62. Encoder of claim 61, configured to
encode a first part of the binarization using context-adaptive entropy encoding, and
encode a second part of the binarization using an equi-probability bypass mode,
wherein the second part of the binarization comprises a prefix part and a suffix part and the binarization parameter determines a length of the prefix part.
63. Encoder of claim 61 or 62, wherein
the binarization comprises a prefix part and a suffix part and the binarization parameter determines a length of the prefix part.
64. Encoder of any of claims 61 to 63, wherein
the binarization parameter is an Exp Golomb order or a Rice parameter.

65. Encoder of any of claims 61 to 64, configured to
set the binarization parameter by mapping the sum of absolute values of quantization lev¬els of the one or more previously encoded transform coefficients using a look-up table onto the binarization parameter.
66. Encoder of any of claims 61 to 64, configured to
encode a first part of the binarization using context-adaptive entropy encoding, and encode a second part of the binarization using an equi-probability bypass mode,
entropy encode bins of the first part (160) of the binarization for quantization levels of transform coefficients of the transform coefficient block (92) sequentially in a plurality of passes, wherein the second part of the binarization (161) comprises a prefix part (162a) and a suffix part (162b) and the binarization parameter determines a length of the prefix part (162a),
determine the binarization parameter based on
a sum over an absolute value of a coefficient level of the one or more pre-viously encoded transform coefficients located at the positions determined by the local template (132) positioned at the currently encoded transform coefficient.
67. Encoder of any of claims 61 to 64, configured to
encode a first part of the binarization using context-adaptive entropy encoding, and encode a second part of the binarization using an equi-probability bypass mode,
entropy encode bins of the first part (160) of the binarization for quantization levels of transform coefficients of the transform coefficient block (92) sequentially in a plurality of passes, wherein the second part of the binarization (161) comprises a prefix part (162a) and a suffix part (162b) and the binarization parameter determines a length of the prefix part (162a),
determine the binarization parameter based on

the number of significant ones among the one or more previously encoded transform coefficients located at the positions determined by the local tem-plate (132) positioned at the currently encoded transform coefficient.
68. Encoder of any of claims 61 to 67, configured to
perform the setting the binarization parameter based on a sum of the one or more previ-ously encoded transform coefficients in a manner so that the binarization parameter is equal to or larger than binarization parameters set and used for absolute values of quanti-zation levels of previously encoded transform coefficients of the transform coefficient block.
69. Decoder for decoding a picture from a data stream, configured to
decode a transform coefficient block (92) representing a block (84) of the picture (12) from the data stream by
decoding an absolute value of a quantization level of a currently decoded transform coefficient of the transform coefficient block in a manner bina-rized using a binarization (161) which is parameterized using a binarization parameter (163),
setting of the binarization parameter (163) based on
a sum of, and/or
a number of significant ones among,
one or more previously decoded transform coefficients located at positions determined by a local template (132) positioned at the currently decoded transform coefficient.
70. Decoder of claim 69, configured to
decode a first part (160) of the binarization using context-adaptive entropy decoding, and decode a second part (162) of the binarization using an equi-probability bypass mode,

wherein the second part of the binarization (161) comprises a prefix part (162a) and a suffix part (162b) and the binarization parameter determines a length of the prefix part (162a).
71. Decoder of claim 69 or 70, wherein
the binarization (161) comprises a prefix part and a suffix part and the binarization param-eter determines a length of the prefix part.
72. Decoder of any of claims 69 to 71, wherein
the binarization parameter is an Exp Golomb order or a Rice parameter.
73. Decoder of any of claims 69 to 72, configured to
set the binarization parameter by mapping the sum of absolute values of quantization lev¬els of the one or more previously encoded transform coefficients using a look-up table onto the binarization parameter.
74. Decoder of any of claims 69 to 73, configured to
decode a first part (160) of the binarization using context-adaptive entropy decoding, and decode a second part (162) of the binarization using an equi-probability bypass mode,
entropy decode bins of the first part (160) of the binarization for quantization levels of transform coefficients of the transform coefficient block (92) sequentially in a plurality of passes, wherein the second part of the binarization (161) comprises a prefix part (162a) and a suffix part (162b) and the binarization parameter determines a length of the prefix part (162a),
determine the binarization parameter (164) based on
a sum over an absolute value of a coefficient level of the one or more pre-viously decoded transform coefficients located at the positions determined by the local template (132) positioned at the currently decoded transform coefficient.
75. Decoder of any of claims 69 to 74, configured to

decode a first part (160) of the binarization using context-adaptive entropy encoding, and decode a second part (162) of the binarization using an equi-probability bypass mode,
entropy decode bins of the first part (160) of the binarization for quantization levels of transform coefficients of the transform coefficient block (92) sequentially in a plurality of passes, wherein the second part of the binarization (161) comprises a prefix part (162a) and a suffix part (162b) and the binarization parameter determines a length of the prefix part (162a)
determine the binarization parameter (164) based on
the number of significant ones among the one or more previously decoded transform coefficients located at the positions determined by the local tem-plate (132) positioned at the currently decoded transform coefficient.
76. Decoder of any of claims 69 to 75, configured to
perform the setting the binarization parameter based on a sum of the one or more previ-ously decoded transform coefficients in a manner so that the binarization parameter is equal to or larger than binarization parameters set and used for absolute values of quanti-zation levels of previously decoded transform coefficients of the transform coefficient block.

77. Encoder for encoding a picture into a data stream, configured to
encode the transform coefficient block (92) representing a block (84) of the picture (12) into the data stream using a scan pattern (94) which sequentially traverses transform coefficients of the transform coefficient block by
encoding an absolute value of quantization levels (106) of the transform coefficients of the transform coefficient block in a manner binarized using a binarization comprising a first binarization code (160) below a cutoff value (164) and a second binarization code (162), prefixed by a codeword of the first binarization code (160) for the cutoff value, above the cutoff value,
adoptively varying the cutoff value for the transform coefficients of the transform coefficient block depending on previously encoded transform co-efficients.
78. Encoder of claim 77, configured to
adaptively vary the cutoff value in a manner so that the cutoff value monotonically decreases during encoding the transform coefficient block (92) including a de¬crease down to zero so that the binarization becomes the second binarization code without the first binarization code.
79. Encoder of any of claims 77 to 78,
wherein the transform coefficient block (92) is partitioned into partitions (120),
wherein the encoder is configured to encode bins (165) of the binarization (161) of the absolute value of the quantization level (106) of the transform coefficients of the transform coefficient block sequentially in passes along, in each pass, a coding order which travers¬es, for each partition (120), all transform coefficients consecutively without any transform coefficient of any other partition therebetween,
wherein the encoder is configured to encode bins of the first binarization code (160) prior to bins of the second binarization code (162),

wherein the encoder is configured to encode the bins of the first binarization code (160) using context-adaptive entropy encoding, and encode the bins of the second binarization code (162) using an equi-probability bypass mode,
wherein the encoder is configured to
set the cutoff value (164) for a currently encoded transform coefficient (130) de-pending on
a number of bins of the first binarization code, previously encoded using context-adaptive entropy encoding, within the transform coefficient block or within a partition in which the currently encoded transform coefficient is lo-cated.
80. Decoder for decoding a picture from a data stream, configured to
decode the transform coefficient block (92) representing a block (84) of the picture (12) from the data stream using a scan pattern (94) which sequentially traverses transform coefficients of the transform coefficient block by
decoding an absolute value of quantization levels (106) of the transform coefficients of the transform coefficient block in a manner binarized using a binarization comprising a first binarization code (160) below a cutoff value (164) and a second binarization code (162), prefixed by a codeword of the first binarization code (160) for the cutoff value, above the cutoff value,
adaptively varying the cutoff value for the transform coefficients of the transform coefficient block depending on previously decoded transform co-efficients.
81. Decoder of claim 80, configured to
adaptively vary the cutoff value in a manner so that the cutoff value monotonically decreases during decoding the transform coefficient block (92) including a de¬crease down to zero so that the binarization becomes the second binarization code without the first binarization code.
82. Decoder of any of claims 80 to 81,

wherein the transform coefficient block (92) is partitioned into partitions (120),
wherein the decoder is configured to decode bins (165) of the binarization (161) of the absolute value of the quantization level (106) of the transform coefficients of the transform coefficient block sequentially in passes along, in each pass, a coding order which travers-es, for each partition (120), all transform coefficients consecutively without any transform coefficient of any other partition therebetween,
wherein the decoder is configured to decode bins of the first binarization code (160) prior to bins of the second binarization code (162),
wherein the decoder is configured to decode the bins of the first binarization code (160) using context-adaptive entropy decoding, and decode the bins of the second binarization code (162) using an equi-probability bypass mode,
wherein the decoder is configured to
set the cutoff value (164) for a currently decoded transform coefficient (130) de-pending on
a number of bins of the first binarization code, previously decoded using context-adaptive entropy encoding, within the transform coefficient block or within a partition in which the currently decoded transform coefficient is lo-cated.

83. Encoder for encoding a picture into a data stream, configured to
encode a transform coefficient block (92) representing a block (84) of the picture (12) into the data stream by
encoding an absolute value of a quantization level (106) of the transform coefficients of the transform coefficient block in a manner binarized using a binarization comprising a first binarization code (160) below a cutoff value [i.e. for absolute values below the cutoff value] and a second binarization code (162), prefixed by a codeword of the first binarization code (160) for the cutoff value, above the cutoff value,
setting the cutoff value (164) depending on one or more of
a size of the block (84), a color component of the block (84),
a prediction mode underlying a prediction signal a prediction residu¬al of which the block (84) represents, a transformation underlying the transform coefficient block (92), a quantization parameter used to quantize the transform coefficient
block (92), a measure of an energy of previously encoded transform coeffi¬cients, and an evaluation of previously encoded transform coefficients.
84. Encoder of claim 83, wherein the previously encoded transform coefficients used
for the evaluation are
located at positions determined by a local template (132) po-sitioned at a currently encoded transform coefficient or
located at positions within a partition of the transform coeffi-cient block (92) offset to a current partition the currently en-coded transform coefficient is located in and preceding the current partition according to a coding order used for encod-ing the absolute value of the quantization level (106) of the transform coefficients of the transform coefficient block de-

fined by traversing the transform coefficients of the transform coefficient block along a scan pattern in a predetermined di¬rection (102).
85. Encoder of claim 83 or 84, configured to
adaptively vary the cutoff value for the transform coefficients of the transform coef-ficient block depending on previously encoded transform coefficients if the cutoff value is initially set to a value succeeding a predetermined threshold, and
keep constant the cutoff value (164) at least preliminarily [e.g. until reaching the last partition in order direction (102) if the cutoff value is initially set to a value ex¬ceeding the predetermined threshold.
86. Encoder of any of claims 83 to 85, configured to
Adaptively vary the cutoff value for the currently encoded transform coeffi-cient based on
a sum of, and/or
a number of significant ones among,
one or more previously encoded transform coefficients located at positions determined by the local template (132) positioned at the currently encoded transform coefficient.
87. Encoder of any claims 83 to 86, configured to
entropy encoding one or more bins of the first binarization context-adaptively us¬ing, for each partition of partitions into which the transform coefficient block is sub-divided, a set of contexts which is associated with the respective partition,
wherein the encoder is configured to perform the setting for a predetermined parti-tion in a manner depending on
an evaluation of previously encoded transform coefficients located in a par-tition which is traversed by the coding order prior to the predetermined par-tition.

88. Encoder of any of claims 83 to 87, configured to
adaptively vary the cutoff value in a manner including setting the cutoff value to ze-ro so that no first binarization exists if a measure of an energy of previously en-coded transform coefficients increases a certain threshold.
89. Encoder of any of claims 83 to 88,
wherein the transform coefficient block (92) is partitioned into partitions,
wherein the encoder is configured to encode bins of the binarization of the absolute value of the quantization level (106) of the transform coefficients of the transform coefficient block sequentially in passes along, in each pass, a coding order which traverses, for each partition, all transform coefficients consecutively without any transform coefficient of any other partition therebetween,
wherein the encoder is configured to encode bins of the first binarization code prior to bins of the second binarization code,
wherein the encoder is configured to encode the bins of the first binarization code using context-adaptive entropy encoding, and encode the bins of the second binarization code using an equi-probability bypass mode,
wherein the encoder is configured to
set the cutoff value (164) depending on
the measure of the energy of the previously encoded transform co-efficients within a partition in which a currently encoded transform coefficient is located.
90. Encoder of claim 89, configured to
Use a number of bins of the first binarization code, previously encoded using context-adaptive arithmetic encoding for the transform coefficients within the partition in which a currently encoded transform coefficient is located, as a measure for the energy.

91. Encoder of any of claims 83 to 88,
wherein the encoder is configured to encode bins of the binarization of the absolute value of the quantization level (106) of the transform coefficients of the transform coefficient block sequentially in passes,
wherein the encoder is configured to encode bins of the first binarization code prior to bins of the second binarization code,
wherein the encoder is configured to encode the bins of the first binarization code using context-adaptive entropy encoding, and encode the bins of the second binarization code using an equi-probability bypass mode,
wherein the encoder is configured to
set the cutoff value (164) depending on
the measure of the energy of the previously encoded transform co-efficients within the transform coefficient block.
92. Encoder of claim 91, configured to
Use a number of bins of the first binarization code, previously encoded using context-adaptive arithmetic encoding for the transform coefficients within the transform coefficient block as a measure for the energy.
93. Encoder of any of claims 83 to 88,
wherein the transform coefficient block (92) is partitioned into partitions,
wherein the encoder is configured to encode bins of the binarization of the absolute value of the quantization level (106) of the transform coefficients of the transform coefficient block sequentially in passes along, in each pass, a coding order which traverses, for each partition, all transform coefficients consecutively without any transfer coefficient of any other partition therebetween,

wherein the encoder is configured to entropy encode bins of the first binarization code prior to bins of the second binarization code,
wherein the encoder is configured to encode the bins of the first binarization code using context-adaptive entropy encoding, and encode the bins of the second binarization code using an equi-probability bypass mode,
wherein the encoder is configured to
set the cutoff value (164) depending on
an evaluation of a number of bins of the first binarization code, previously encoded using context-adaptive entropy encoding for transform coefficients locat¬ed at positions determined by a local template (132) positioned at a currently en¬coded transform coefficient, with using a partition the current encoded transform coefficient is located in as the locale template.
94. Decoder for decoding a picture from a data stream, configured to
decode a transform coefficient block (92) representing a block (84) of the picture (12) from the data stream by
decoding an absolute value of a quantization level (106) of the transform coefficients of the transform coefficient block in a manner binarized using a binarization (161) comprising a first binarization code (160) below a cutoff value [i.e. for absolute values below the cutoff value] and a second binari-zation code (162), prefixed by a codeword of the first binarization code (160) for the cutoff value, above the cutoff value,
setting the cutoff value (164) depending on one or more of
a size of the block (84),
a color component of the block (84),
a prediction mode underlying a prediction signal a prediction residu¬al of which the block (84) represents,
a transformation underlying the transform coefficient block (92),
a quantization parameter used to quantize the transform coefficient block (92),

a measure of an energy of previously decoded transform coeffi-cients, an evaluation of previously decoded transform coefficients.
95. Decoder of claim 94, wherein the previously decoded transform coefficients used
for the evaluation are
located at positions determined by a local template (132) po-sitioned at a currently decoded transform coefficient or
located at positions within a partition of the transform coeffi-cient block (92) offset to a current partition the currently de-coded transform coefficient is located in and preceding the current partition according to a coding order used for decod-ing the absolute value of the quantization level (106) of the transform coefficients of the transform coefficient block de-fined by traversing the transform coefficients of the transform coefficient block along a scan pattern in a predetermined di-rection (102).
96. Decoder of claim 94 or 95, configured to
adaptively vary the cutoff value for the transform coefficients of the transform coef-ficient block depending on previously decoded transform coefficients if the cutoff value is initially set to a value succeeding a predetermined threshold, and
keep constant the cutoff value (164) at least preliminarily [e.g. until reaching the last partition in order direction 102) if the cutoff value is initially set to a value ex¬ceeding the predetermined threshold.
97. Decoder of any of claims 94 to 96, configured to
Adaptively vary the cutoff value for the currently encoded transform coeffi-cient based on
a sum of, and/or
a number of significant ones among,

one or more previously encoded transform coefficients located at positions determined by the local template (132) positioned at the currently decoded transform coefficient.
98. Decoder of any claims 94 to 97, configured to
entropy decoding one or more bins of the binarization context-adaptively using, for each partition of partitions into which the transform coefficient block is subdivided, a set of contexts which is associated with the respective partition,
wherein the decoder is configured to perform the setting for a predetermined parti-tion in a manner depending on
an evaluation of previously decoded transform coefficients located in a par-tition which is traversed by the coding order prior to the predetermined par-tition.
99. Decoder of any of claims 94 to 98, configured to
adaptively vary the cutoff value in a manner including setting the cutoff value to ze-ro so that first binarization exists if a measure of an energy of previously decoded transform coefficients increases a certain threshold.
100. Decoder of any of claims 94 to 99,
wherein the transform coefficient block (92) is partitioned into partitions,
wherein the decoder is configured to decode bins of the binarization of the absolute value of the quantization level (106) of the transform coefficients of the transform coefficient block sequentially in passes along, in each pass, a coding order which traverses, for each partition, all transform coefficients consecutively without any transform coefficient of any other partition therebetween,
wherein the decoder is configured to decode bins of the first binarization code prior to bins of the second binarization code,
wherein the decoder is configured to decode the bins of the first binarization code using context-adaptive entropy decoding, and decode the bins of the second binarization code using an equi-probability bypass mode,

wherein the decoder is configured to
set the cutoff value (164) depending on
the measure of the energy of the previously decoded transform co-efficients within a partition in which a currently decoded transform coefficient is located.
101. Decoder of claim 100, configured to
Use a number of bins of the first binarization code, previously decoded using context-adaptive arithmetic decoding for the transform coefficients within the partition in which a currently decoded transform coefficient is located, as a measure for the energy.
102. Decoder of any of claims 94 to 99,
wherein the decoder is configured to deode bins of the binarization of the absolute value of the quantization level (106) of the transform coefficients of the transform coefficient block sequentially in passes,
wherein the decoder is configured to decode bins of the first binarization code prior to bins of the second binarization code,
wherein the decoder is configured to decode the bins of the first binarization code using context-adaptive entropy decoding, and decode the bins of the second binarization code using an equi-probability bypass mode,
wherein the decoder is configured to
set the cutoff value (164) depending on
the measure of the energy of the previously decoded transform co-efficients within the transform coefficient block.
103. Decoder of claim 102, configured to

Use a number of bins of the first binarization code, previously decoded using context-adaptive arithmetic decoding for the transform coefficients within the transform coefficient block as a measure for the energy.
104. Decoder of any of claims 94 to 99,
wherein the transform coefficient block (92) is partitioned into partitions,
wherein the decoder is configured to decode bins of the binarization of the absolute value of the quantization level (106) of the transform coefficients of the transform coefficient block sequentially in passes along, in each pass, a coding order which traverses, for each partition, all transform coefficients consecutively without any transform coefficient of any other partition therebetween,
wherein the decoder is configured to decode bins of the first binarization code prior to bins of the second binarization code,
wherein the decoder is configured to decode the bins of the first binarization code using context-adaptive entropy decoding, and decode the bins of the second binarization code using an equi-probability bypass mode,
wherein the decoder is configured to
set the cutoff value (164) for a currently decoded transform coefficient depending on
an evaluation of a number of bins of the first binarization code, previously decoded using context-adaptive entropy decoding for transform coefficients locat¬ed at positions determined by a local template (132) positioned at the currently de-coded transform coefficient, with using a partition the current decoded transform coefficient is located in as the locale template.

105. Encoder for encoding a picture into a data stream, configured to
entropy encoding a quantization level of a currently encoded transform coefficient of a transform coefficient block (92) representing a block (84) of the picture (12) context-adaptively by
setting a shape of a local template (132) or disabling the local template (132) [so that the template-specific context dependency is disabled] de¬pending on
previously encoded transform coefficients and/or depending on one or more of a size of the block (84), a color component of the block (84),
a position of a termination coefficient position at which, when traversing the scan pattern along a forward direction (116), a last non-zero transform coefficient resides, a transformation underlying the transform coefficient block (92),
use of a context which is
determined based on one or more previously encoded transform coefficients located at positions determined by the local template (132) positioned at the currently encoded transform coefficient, or if the local template disabled, is independent from previously encoded transform coefficients.
106. Encoder according to claim 105, configured to
in setting a shape of, or disabling, the local template depending on the previously
encoded transform coefficients,
set the shape of the local template depending on one or more previously encoded transform coefficients located at positions determined by a first lo-cal primitive template (170) positioned at the currently encoded transform coefficient.

107. Encoder according to claim 105, configured to
in setting a shape of, or disabling, the local template depending on the previously encoded transform coefficients,
decide depending on one or more previously encoded transform coeffi¬cients located at positions determined by a first local primitive template (170) positioned at the currently encoded transform coefficient, whether the shape of the local template (132) shall be
the first local primitive template (170) or
a second primitive template (172), wherein the second primitive template extends farther away from the currently encoded transform coefficient than the first second primitive template and includes or not includes the positions determined by the first local primitive tem¬plate.
108. Encoder according to claim 10, configured to
Perform the decision depending on a sum of, or a number of significant ones among, the one or more previously encoded transform coefficients located at posi-tions determined by the first local primitive template (170) positioned at the current¬ly encoded transform coefficient.
109. Encoder according to any of claims 105 to 107, configured to
disable the local template,
if an accumulative value derived based on previously encoded transform coefficients within the transform coefficient block or a count of previously encoded transform coefficients within the transform coefficient block being greater than some threshold, exceeds a predetermined amount, and/or
disable the local template,
if a count of previously encoded transform coefficients within the transform coefficient block being insignificant, exceeds a predetermined amount.
110. Encoder according to any of claims 105 to 109, configured to
determine the context based on a sum of, or a number of significant ones among, the one or more previously encoded transform coefficients located at the positions

determined by the local template positioned at the currently encoded transform co-efficient.
111. Encoder of any of claims 105 to 110, configured to
entropy encode the quantization level using context-adaptive binary arithmetic cod-ing of a binarization of an absolute value of the quantization level involving a prefix part and a suffix part, wherein the context is used for one or more bins of the prefix part.
112. Encoder of any of claims 105 to 111, configured to
encode bins of a binarization for quantization levels of transform coefficients of the transform coefficient block (92) sequentially in a plurality of passes,
use the context for at least one bin of the binarization of the quantization level of currently encoded transform coefficient, and
determine the context based on previously encoded bins of the binarization of the absolute value of the coefficient level of the one or more previously encoded trans-form coefficients, or, if the local template disabled, independent from the previously encoded bins of the binarization of the absolute value of the coefficient level of the one or more previously encoded transform coefficients.
113. Decoder for decoding a picture from a data stream, configured to
entropy decoding a quantization level of a currently decoded transform coefficient of a transform coefficient block (92) representing a block (84) of the picture (12) context-adaptively by
setting a shape of a local template (132) or disabling the local template (132) [so that the template-specific context dependency is disabled] de¬pending on
previously decoded transform coefficients and/or
depending on one or more of a size of the block (84),

a position of a termination coefficient position at which, when traversing the scan pattern along a forward direction (116), a last non-zero transform coefficient resides, a transformation underlying the transform coefficient block (92),
use of a context which is
determined based on one or more previously decoded transform coefficients located at positions determined by the local template (130) positioned at the currently decoded transform coefficient, or if the local template disabled, is independent from previously de¬coded transform coefficients.
114. Decoder according to claim 113, configured to
in setting a shape of, or disabling, the local template depending on the previously
decoded transform coefficients,
set the shape of the local template depending on one or more previously decoded transform coefficients located at positions determined by a first lo-cal primitive template (170) positioned at the currently decoded transform coefficient (130).
115. Decoder according to claim 113, configured to
in setting a shape of, or disabling, the local template depending on the previously decoded transform coefficients,
decide depending on one or more previously decoded transform coeffi¬cients located at positions determined by a first local primitive template (170) positioned at the currently decoded transform coefficient, whether the shape of the local template (132) shall be
the first local primitive template (170) or
a second primitive template (172), wherein the second primitive template extends farther away from the currently decoded transform coefficient than the first second primitive template and includes or not includes the positions determined by the first local primitive tem-plate.
116. Decoder according to claim 115, configured to

Perform the decision depending on a sum of, or a number of significant ones among, the one or more previously decoded transform coefficients located at posi-tions determined by the first local primitive template (170) positioned at the current¬ly decoded transform coefficient.
117. Decoder according to any of claims 113 to 115, configured to
disable the local template,
if an accumulative value derived based on previously decoded transform coefficients within the transform coefficient block or a count of previously decoded transform coefficients within the transform coefficient block being greater than some threshold, exceeds a predetermined amount, and/or
disable the local template,
if a count of previously decoded transform coefficients within the transform coefficient block being insignificant, exceeds a predetermined amount.
118. Decoder according to any of claims 113 to 117, configured to
determine the context based on a sum of, or a number of significant ones among, the one or more previously decoded transform coefficients located at the positions determined by the local template positioned at the currently decoded transform co-efficient.

119. Encoder for encoding a picture into a data stream, configured to
encode a transform coefficient (92) of a transform coefficient block (92) represent-ing a block (84) of the picture (12) by
entropy encoding quantization levels (106) of the transform coefficients of the transform coefficient block context-adaptively using, for each partition of partitions into which the transform coefficient block is subdivided, a set of contexts which is associated with the respective partition,
wherein the partitions into which the transform coefficient block is subdivided,
vary in shape and/or
are shaped depending on a scanning pattern along which the entropy en-coding the quantization levels of the transform coefficients of the transform coefficient block is performed, and/or are shaped depending on a size of the block (84), and/or are shaped depending on explicit partition shaping information.
120. Encoder of claim 119, configured to
entropy encode the quantization levels of the transform coefficients of the trans¬form coefficient block context-adaptively sequentially by following a scan pattern which sequentially traverses transform coefficients of the transform coefficient block in a manner traversing the partitions sequentially without interleaving trans¬form coefficients of different partitions.
121. Encoder of claim 119 or 120, wherein the partitions into which the transform coeffi¬
cient block is subdivided,
Extend diagonally along a direction obliquely to a normal direction through a DC transform coefficient of the transform coefficient block.
122. Encoder of any claims 119 to 121, configured to
encode a transform coefficient of a transform coefficient block (92) representing a block (84) of the picture (12) by

encoding for each partition of a set of partitions into which the transform coefficient block is subdivided an indication (150) whether all transform co-efficients within the respective partition are encoded into the data stream, or whether the encoding of all transform coefficients within the respective partition is skipped and all transform coefficients within the respective parti-tion are zero, and
entropy encoding, for each partition for which the indication indicates that all transform coefficients within the respective partition are encoded into the data stream, quantization levels of all transform coefficients of the respec¬tive partition context-adaptively using a set of contexts which is associated with the respective partition.
123. Decoder for decoding a picture from a data stream, configured to
decode a transform coefficient (92) of a transform coefficient block (92) represent-ing a block (84) of the picture (12) by
entropy decoding quantization levels (106) of the transform coefficients of the transform coefficient block context-adaptively using, for each partition of partitions into which the transform coefficient block is subdivided, a set of contexts which is associated with the respective partition,
wherein the partitions into which the transform coefficient block is subdivided,
vary in shape and/or
are shaped depending on a scanning pattern along which the entropy de-coding the quantization levels of the transform coefficients of the transform coefficient block is performed, and/or are shaped depending on a size of the block (84), and/or are shaped depending on explicit partition shaping information.
124. Decoder of claim 123, configured to
entropy decode the quantization levels of the transform coefficients of the trans¬form coefficient block context-adaptively sequentially by following a scan pattern which sequentially traverses transform coefficients of the transform coefficient

block in a manner traversing the partitions sequentially without interleaving trans-form coefficients of different partitions.
125. Decoder of claim 123 or 124, wherein the partitions into which the transform coeffi¬
cient block is subdivided,
Extend diagonally along a direction obliquely to a normal direction through a DC transform coefficient of the transform coefficient block.
126. Encoder of any claims 123 to 125, configured to
encode a transform coefficient of a transform coefficient block (92) representing a block (84) of the picture (12) by
encoding for each partition of a set of partitions into which the transform coefficient block is subdivided an indication (150) whether all transform co-efficients within the respective partition are encoded into the data stream, or whether the encoding of all transform coefficients within the respective partition is skipped and all transform coefficients within the respective parti-tion are zero, and
entropy encoding, for each partition for which the indication indicates that all transform coefficients within the respective partition are encoded into the data stream, quantization levels of all transform coefficients of the respec¬tive partition context-adaptively using a set of contexts which is associated with the respective partition.

127. Encoder for encoding a picture into a data stream, configured to
encode a transform coefficient block (92) representing a block (84) of the picture (12) by
encoding for each partition of a set of partitions into which the transform coefficient block is subdivided an indication (150) whether all transform co-efficients within the respective partition are encoded into the data stream, or whether the encoding of all transform coefficients within the respective partition is skipped and all transform coefficients within the respective parti-tion are zero, and
entropy encoding, for each partition for which the indication indicates that all transform coefficients within the respective partition are encoded into the data stream, quantization levels of all transform coefficients of the respec-tive partition.
128. Encoder according to claim 127, configured to
entropy encode, for each partition for which the indication indicates that all trans-form coefficients within the respective partition are encoded into the data stream, the quantization levels of all transform coefficients of the respective partition by
entropy encoding, for a last transform coefficient of the of the respective partition which is encoded last among the transform coefficients of the re-spective partition, a flag indicating whether the last transform coefficient is zero or not, irrespective of whether any of the previously encoded transform coefficients within the respective partition are all zero or not.
129. Decoder for decoding a picture from a data stream, configured to
decode a transform coefficient block (92) representing a block (84) of the picture (12) by
decoding for each partition of a set of partitions into which the transform coefficient block is subdivided an indication (150) whether all transform co-efficients within the respective partition are decoded into the data stream, or whether the decoding of all transform coefficients within the respective

partition is skipped and all transform coefficients within the respective parti-tion are zero, and
entropy decoding, for each partition for which the indication indicates that all transform coefficients within the respective partition are decoded into the data stream, quantization levels of all transform coefficients of the respec-tive partition.
130. Decoder according to claim 129, configured to
entropy decode, for each partition for which the indication indicates that all trans-form coefficients within the respective partition are decoded into the data stream, the quantization levels of all transform coefficients of the respective partition by
entropy decoding, for a last transform coefficient of the of the respective partition which is decoded last among the transform coefficients of the re-spective partition, a flag indicating whether the last transform coefficient is zero or not, irrespective of whether any of the previously decoded transform coefficients within the respective partition are all zero or not.

131. Encoder for encoding a picture into a data stream, configured to
encoding a partitioning mode of a transform coefficient block (92) representing a block (84) of the picture (12) into the data stream,
encode the transform coefficient block by
if the partition mode is a first mode [e.g. partition into partitions 120 switched on], entropy encoding quantization levels of the transform coeffi¬cients of the transform coefficient block context-adaptively using, for each partition of partitions into which the transform coefficient block is subdivid¬ed, a set of contexts which is associated with the respective partition, and
if the partition mode is a second mode [e.g. partition into partitions 120 switched off], entropy encoding the quantization levels of the transform co-efficients of the transform coefficient block context-adaptively using a global set of contexts.
132. Encoder according to claim 131, configured to
if the partition mode is the first mode,
encode for each partition of a set of partitions an indication whether the quantization levels of the transform coefficients within the respective parti-tion are encoded into the data stream, or whether the encoding of the quan-tization levels of the transform coefficients within the respective partition is skipped and all transform coefficients within the respective partition are ze¬ro, and
skip, in entropy encoding the quantization levels of the transform coeffi-cients, the entropy encoding with respect to partitions for which the indica-tion indicates that the encoding of the quantization levels of the transform coefficients within the partitions is skipped and all transform coefficients within the partitions are zero.

133. Decoder for decoding a picture from a data stream, configured to
decoding a partitioning mode of a transform coefficient block (92) representing a block (84) of the picture (12) from the data stream,
decode the transform coefficient block by
if the partition mode is a first mode [e.g. partition into partitions 120 switched on], entropy decoding quantization levels of the transform coeffi¬cients of the transform coefficient block context-adaptively using, for each partition of partitions into which the transform coefficient block is subdivid¬ed, a set of contexts which is associated with the respective partition, and
if the partition mode is a second mode [e.g. partition into partitions 120 switched off], entropy decoding the quantization levels of the transform co-efficients of the transform coefficient block context-adaptively using a global set of contexts .
134. Decoder according to claim 133, configured to
if the partition mode is the first mode,
decode for each partition of a set of partitions an indication whether the quantization levels of the transform coefficients within the respective parti-tion are decoded into the data stream, or whether the decoding of the quan-tization levels of the transform coefficients within the respective partition is skipped and all transform coefficients within the respective partition are ze¬ro, and
skip, in entropy decoding the quantization levels of the transform coeffi-cients, the entropy decoding with respect to partitions for which the indica¬tion indicates that the decoding of the quantization levels of the transform coefficients within the partitions is skipped and all transform coefficients within the partitions are zero.

135. Encoder for encoding a picture into a data stream, configured to
encode a transform coefficient block (92) representing a block (84) of the picture (12) into the data stream (14) using a scan pattern (94') which sequentially traverses transform coefficients (91) of the transform coefficient block by
entropy encoding quantization levels (106) of the transform coefficients of the transform coefficient block context-adaptively using, for each partition of partitions (120a,b,c) into which the transform coefficient block is subdivided, a set (110a,b,c) of contexts which is associated (126) with the respective partition (120),
wherein the scan pattern (94') sequentially traverses the transform coefficients (91) of the transform coefficient block (92) in a manner so that at least one transform coefficient (such as the hatched ones 91') of a first partition (e.g. 120a or 120c) is traversed between two transform coefficients of a second partition (e.g. 120b).
136. Encoder according to claim 135, configured so that one set of contexts is common¬ly associated with the first partition and second partitions (e.g. 120a or 120c).
137. Encoder according to claim 135 or 136, configured to
in entropy encoding the quantization levels of the transform coefficients of the transform coefficient block (92) context-adaptively,
determine for a currently encoded transform coefficient (130) a context out of the set (110) of contexts (112) associated with the partition (e.g. 120a) the currently encoded transform coefficient is located in, based on
one or more previously encoded transform coefficients located at positions determined by a local template (132) positioned at the cur-rently encoded transform coefficient.
138. Encoder according to claim 135 or 136, configured to
in entropy encoding the quantization levels of the transform coefficients of the transform coefficient block context-adaptively,

determine for a currently encoded transform coefficient a context out of the set of contexts associated with the partition the currently encoded transform coefficient is located in, based on
one or more previously encoded transform coefficients located at positions determined by a local template (132) positioned at the cur-rently encoded transform coefficient, irrespective of whether the po-sitions are within the partition the currently encoded transform coef-ficient is located in, and/or
a count (exemplarily 4 in the example figure) of previously encoded transform coefficients (e.g. hatched ones 140) located within the partition (e.g. 120a) the currently encoded transform coefficient (130) is located in, which exceed one or more certain thresholds.
139. Encoder according to any of claims 135 to 137, configured to
encoding for each partition (120a,b,c) of a set of partitions into which the transform coefficient block (92) is subdivided an indication (150) whether the transform coef-ficients within the respective partition are encoded into the data stream, or whether the encoding of the transform coefficients within the respective partition is skipped and all transform coefficients within the respective partition are zero, and skipping, in entropy encoding the quantization levels of the transform coefficients, the entro¬py encoding with respect to partitions for which the indication indicates that the en-coding of the transform coefficients within the partitions is skipped and all trans¬form coefficients within the partitions are zero.
140. Encoder according to claim 139, configured to
encoding the indication (150) into the data stream in between the quantization lev¬els of transform coefficients within partitions for which the indication indicates that the transform coefficients within the respective partition are encoded into the data stream (e.g. for 1201 and 1203), in place of [in case of CBF being zero such as CBF2 in the example], or in front of [in case of CBF being one such as CBF3 in the example], a first encountered transform coefficient within the partition the indication relates to.
141. Decoder for decoding a picture from a data stream, configured to

decode a transform coefficient block (92) representing a block (84) of the picture (12) from the data stream (14) using a scan pattern (94') which sequentially traverses transform coefficients (91) of the transform coefficient block by
entropy decoding quantization levels (106) of the transform coefficients of the transform coefficient block context-adaptively using, for each partition of partitions into which the transform coefficient block is subdivided, a set (110a,b,c) of contexts which is associated (126) with the respective parti¬tion (120),
wherein the scan pattern (94') sequentially traverses the transform coefficients (91) of the transform coefficient block (92) in a manner so that at least one transform coefficient (such as the hatched ones 91') of a first partition is traversed between two transform coefficients of a second partition.
142. Decoder according to claim 141, configured so that one set of contexts is common-ly associated with the first partition and second partitions (e.g. 120a or 120c).
143. Decoder according to claim 141 or 142, configured to
in entropy decoding the quantization levels of the transform coefficients of the transform coefficient block (92) context-adaptively,
determine for a currently encoded transform coefficient (130) a context out of the set (110) of contexts (112) associated with the partition (e.g. 120a) the currently decoded transform coefficient is located in, based on
one or more previously encoded transform coefficients located at positions determined by a local template (132) positioned at the cur-rently decoded transform coefficient.
144. Decoder according to claim 141 or 142, configured to
in entropy decoding the quantization levels of the transform coefficients of the transform coefficient block context-adaptively,

determine for a currently decoded transform coefficient a context out of the set of contexts associated with the partition the currently decoded transform coefficient is located in, based on
one or more previously decoded transform coefficients located at positions determined by a local template (132) positioned at the cur-rently decoded transform coefficient, irrespective of whether the po-sitions are within the partition the currently decoded transform coef-ficient is located in, and/or
a count (exemplarily 4 in the example figure) of previously decoded transform coefficients (e.g. hatched ones 140) located within the partition (e.g. 120a) the currently decoded transform coefficient (130) is located in, which exceed one or more certain thresholds.
145. Decoder according to any of claims 141 to 143, configured to
decoding for each partition (120a,b,c) of a set of partitions into which the transform coefficient block (92) is subdivided an indication (150) whether the transform coef-ficients within the respective partition are decoded into the data stream, or whether the decoding of the transform coefficients within the respective partition is skipped and all transform coefficients within the respective partition are zero, and skipping, in entropy decoding the quantization levels of the transform coefficients, the entro¬py decoding with respect to partitions for which the indication indicates that the de-coding of the transform coefficients within the partitions is skipped and all trans¬form coefficients within the partitions are zero.
146. Encoder according to claim 145, configured to
decoding the indication (150) from the data stream in between the quantization levels of transform coefficients within partitions for which the indication indicates that the transform coefficients within the respective partition are decoded into the data stream (e.g. for 120-1 and 1203), in place of [in case of CBF being zero such as CBF2 in the example], or in front of [in case of CBF being one such as CBF3 in the example], a first encountered transform coefficient within the partition the indi-cation relates to.
147. Method for encoding a picture into a data stream, comprising;

subjecting a block of the picture separately for a first color component and a sec-ond color component to a transformation to obtain a first transform coefficient block and a second transform coefficient block, respectively,
entropy encoding the second transform coefficient block context-adaptively using a context which depends on the first transform coefficient block.
148. Method for decoding a picture from a data stream, comprising;
deriving a block (84) of the picture by, separately for a first color component and a second color component, a reverse transformation of a first transform coefficient block (921) and a second transform block (922), respectively,
entropy decoding the second transform coefficient block (922) context-adaptively using a context which depends on the first transform coefficient block.
149. Method for encoding a picture (12) into a data stream (14), comprising;
encoding (108) a transform coefficient block (92) representing a block (84) of the picture (12) into the data stream (14) using a scan pattern (94) which sequentially traverses transform coefficients of the transform coefficient block (92) by
encoding into the data stream (14) data (96) representing a coded set (100 shown hatched) of transform coefficients (91) traversed by the scan pattern (94) [or scan path] from a first termination coefficient position (98) in a pre-determined direction (102) to a second termination coefficient (104), the da-ta (96) comprising quantization levels (106) of the transform coefficients in the coded set (100) of transform coefficients,
wherein the method comprises entropy encoding the quantization levels (106) con-text-adaptively using a first set (110) of contexts (112) for the quantization level of the transform coefficient at the first termination coefficient position (98) or at the second termination coefficient position (104) which is disjoint to a second set (110) of contexts (112) used for any other transform coefficient in the coded set (100) of transform coefficients.
150 Method for decoding a picture (12) from a data stream (14), comprising:

decoding (108) a transform coefficient block (92) representing a block (84) of the picture (12) from the data stream (14) using a scan pattern (94) which sequentially traverses transform coefficients (91) of the transform coefficient block (92) by
decoding from the data stream (14) data (96) representing a coded set (100) of transform coefficients (91) traversed by the scan pattern (94) from a first termination coefficient position (98) in a predetermined direction (102) to a second termination coefficient position (104), the data (96) com¬prising quantization levels (106) of the transform coefficients in the coded set (100) of transform coefficients,
wherein the method comprises entropy decoding the quantization levels (106) con-text-adaptively using a first set (110) of contexts (112) for the quantization level of the transform coefficient at the first termination coefficient position (98) or at the second termination coefficient position (104) which is disjoint to a second set (110) of contexts (112) used for any other transform coefficient in the coded set (100) of transform coefficients.
151. Method for encoding a picture into a data stream, comprising
entropy encoding a quantization level of a currently encoded transform coefficient of a transform coefficient block (92) representing a block (84) of the picture (12) context-adaptively by
use of a context which is determined based on
a sum of, and/or
a number of significant ones among,
one or more previously encoded transform coefficients located at positions determined by a local template (132) positioned at the currently encoded transform coefficient.
152. Method for decoding a picture from a data stream, comprising:
entropy decoding a quantization level (106) of a currently decoded transform coef-ficient (130) of a transform coefficient block (92) representing a block (84) of the picture (12) context-adaptiveiy by

use of a context which is determined based on
a sum of, and/or
a number of significant ones among,
one or more previously decoded transform coefficients located at positions determined by a local template (132) positioned at the currently decoded transform coefficient.
153. Method for encoding a picture into a data stream, comprising:
encoding a transform coefficient block (92) representing a block (84) of the picture (12) into the data stream by
encoding an absolute value of a quantization level of a currently encoded transform coefficient of the transform coefficient block in a manner bina-rized using a binarization (161) which is parameterized using a binarization parameter (163),
setting of the binarization parameter based on
a sum of, and/or
a number of significant ones among,
one or more previously encoded transform coefficients located at positions determined by a local template (132) positioned at the currently encoded transform coefficient.
154. Method for decoding a picture from a data stream, comprising:
decoding a transform coefficient block (92) representing a block (84) of the picture (12) from the data stream by
decoding an absolute value of a quantization level of a currently decoded transform coefficient of the transform coefficient block in a manner bina-rized using a binarization (161) which is parameterized using a binarization parameter (163),

setting of the binarization parameter (163) based on
a sum of, and/or
a number of significant ones among,
one or more previously decoded transform coefficients located at positions determined by a local template (132) positioned at the currently decoded transform coefficient.
155. Method for encoding a picture into a data stream, comprising:
encoding the transform coefficient block (92) representing a block (84) of the pic-ture (12) into the data stream using a scan pattern (94) which sequentially travers¬es transform coefficients of the transform coefficient block by
encoding an absolute value of quantization levels (106) of the transform coefficients of the transform coefficient block in a manner binarized using a binarization comprising a first binarization code (160) below a cutoff value (164) and a second binarization code (162), prefixed by a codeword of the first binarization code (160) for the cutoff value, above the cutoff value,
adaptively varying the cutoff value for the transform coefficients of the transform coefficient block depending on previously encoded transform co-efficients.
156. Method for decoding a picture from a data stream, comprising;
decoding the transform coefficient block (92) representing a block (84) of the pic-ture (12) from the data stream using a scan pattern (94) which sequentially traverses transform coefficients of the transform coefficient block by
decoding an absolute value of quantization levels (106) of the transform coefficients of the transform coefficient block in a manner binarized using a binarization comprising a first binarization code (160) below a cutoff value (164) and a second binarization code (162), prefixed by a codeword of the first binarization code (160) for the cutoff value, above the cutoff value,

adaptively varying the cutoff value for the transform coefficients of the transform coefficient block depending on previously decoded transform co-efficients.
157. Method for encoding a picture into a data stream, comprising:
encoding a transform coefficient block (92) representing a block (84) of the picture (12) into the data stream by
encoding an absolute value of a quantization level (106) of the transform coefficients of the transform coefficient block in a manner binarized using a binarization comprising a first binarization code (160) below a cutoff value [i.e. for absolute values below the cutoff value] and a second binarization code (162), prefixed by a codeword of the first binarization code (160) for the cutoff value, above the cutoff value,
setting the cutoff value (164) depending on one or more of
a size of the block (84), a color component of the block (84),
a prediction mode underlying a prediction signal a prediction residu¬al of which the block (84) represents, a transformation underlying the transform coefficient block (92), a quantization parameter used to quantize the transform coefficient
block (92), a measure of an energy of previously encoded transform coeffi¬cients, and an evaluation of previously encoded transform coefficients.
158. Method for decoding a picture from a data stream, comprising:
decoding a transform coefficient block (92) representing a block (84) of the picture (12) from the data stream by
decoding an absolute value of a quantization level (106) of the transform coefficients of the transform coefficient block in a manner binarized using a binarization (161) comprising a first binarization code (160) below a cutoff value [i.e. for absolute values below the cutoff value] and a second binari-

zation code (162), prefixed by a codeword of the first binarization code (160) for the cutoff value, above the cutoff value,
setting the cutoff value (164) depending on one or more of
a size of the block (84), a color component of the block (84),
a prediction mode underlying a prediction signal a prediction residu¬al of which the block (84) represents, a transformation underlying the transform coefficient block (92), a quantization parameter used to quantize the transform coefficient
block (92), a measure of an energy of previously decoded transform coeffi¬cients, an evaluation of previously decoded transform coefficients.
159. Method for encoding a picture into a data stream, comprising:
entropy encoding a quantization level of a currently encoded transform coefficient of a transform coefficient block (92) representing a block (84) of the picture (12) context-adaptively by
setting a shape of a local template (132) or disabling the local template (132) [so that the template-specific context dependency is disabled] de¬pending on
previously encoded transform coefficients and/or depending on one or more of a size of the block (84), a color component of the block (84),
a position of a termination coefficient position at which, when traversing the scan pattern along a forward direction (116), a last non-zero transform coefficient resides, a transformation underlying the transform coefficient block (92),
use of a context which is

determined based on one or more previously encoded transform coefficients located at positions determined by the local template (132) positioned at the currently encoded transform coefficient, or if the local template disabled, is independent from previously encoded transform coefficients.
160. Method for decoding a picture from a data stream, comprising:
entropy decoding a quantization level of a currently decoded transform coefficient of a transform coefficient block (92) representing a block (84) of the picture (12) context-adaptively by
setting a shape of a local template (132) or disabling the local template (132) [so that the template-specific context dependency is disabled] de¬pending on
previously decoded transform coefficients and/or depending on one or more of a size of the block (84),
a position of a termination coefficient position at which, when traversing the scan pattern along a forward direction (116), a last non-zero transform coefficient resides, a transformation underlying the transform coefficient block (92),
use of a context which is
determined based on one or more previously decoded transform coefficients located at positions determined by the local template (130) positioned at the currently decoded transform coefficient, or if the local template disabled, is independent from previously de¬coded transform coefficients.
161. Method for encoding a picture into a data stream, comprising;
encoding a transform coefficient (92) of a transform coefficient block (92) repre-senting a block (84) of the picture (12) by
entropy encoding quantization levels (106) of the transform coefficients of the transform coefficient block context-adaptively using, for each partition of

partitions into which the transform coefficient block is subdivided, a set of contexts which is associated with the respective partition,
wherein the partitions into which the transform coefficient block is subdivided,
vary in shape and/or
are shaped depending on a scanning pattern along which the entropy en-coding the quantization levels of the transform coefficients of the transform coefficient block is performed, and/or are shaped depending on a size of the block (84), and/or are shaped depending on explicit partition shaping information.
162. Method for decoding a picture from a data stream, comprising:
decoding a transform coefficient (92) of a transform coefficient block (92) repre-senting a block (84) of the picture (12) by
entropy decoding quantization levels (106) of the transform coefficients of the transform coefficient block context-adaptively using, for each partition of partitions into which the transform coefficient block is subdivided, a set of contexts which is associated with the respective partition,
wherein the partitions into which the transform coefficient block is subdivided,
vary in shape and/or
are shaped depending on a scanning pattern along which the entropy de-coding the quantization levels of the transform coefficients of the transform coefficient block is performed, and/or are shaped depending on a size of the block (84), and/or are shaped depending on explicit partition shaping information.
163. Method for encoding a picture into a data stream, comprising:
encoding a transform coefficient block (92) representing a block (84) of the picture (12) by
encoding for each partition of a set of partitions into which the transform coefficient block is subdivided an indication (150) whether all transform co-

efficients within the respective partition are encoded into the data stream, or whether the encoding of all transform coefficients within the respective partition is skipped and all transform coefficients within the respective parti-tion are zero, and
entropy encoding, for each partition for which the indication indicates that ail transform coefficients within the respective partition are encoded into the data stream, quantization levels of ail transform coefficients of the respec¬tive partition.
164. Method for decoding a picture from a data stream, comprising:
decoding a transform coefficient block (92) representing a block (84) of the picture (12) by
decoding for each partition of a set of partitions into which the transform coefficient block is subdivided an indication (150) whether all transform co-efficients within the respective partition are decoded into the data stream, or whether the decoding of all transform coefficients within the respective partition is skipped and all transform coefficients within the respective parti-tion are zero, and
entropy decoding, for each partition for which the indication indicates that all transform coefficients within the respective partition are decoded into the data stream, quantization levels of all transform coefficients of the respec¬tive partition.
165. Method for encoding a picture into a data stream, comprising:
encoding a partitioning mode of a transform coefficient block (92) representing a block (84) of the picture (12) into the data stream,
encoding the transform coefficient block by
if the partition mode is a first mode [e.g. partition into partitions 120 switched on], entropy encoding quantization levels of the transform coeffi¬cients of the transform coefficient block context-adaptively using, for each

partition of partitions into which the transform coefficient block is subdivid¬ed, a set of contexts which is associated with the respective partition, and
if the partition mode is a second mode [e.g. partition into partitions 120 switched off], entropy encoding the quantization levels of the transform co-efficients of the transform coefficient block context-adaptively using a global set of contexts.
166. Method for decoding a picture from a data stream, comprising:
decoding a partitioning mode of a transform coefficient block (92) representing a block (84) of the picture (12) from the data stream,
decoding the transform coefficient block by
if the partition mode is a first mode [e.g. partition into partitions 120 switched on], entropy decoding quantization levels of the transform coeffi¬cients of the transform coefficient block context-adaptively using, for each partition of partitions into which the transform coefficient block is subdivid¬ed, a set of contexts which is associated with the respective partition, and
if the partition mode is a second mode [e.g. partition into partitions 120 switched off], entropy decoding the quantization levels of the transform co-efficients of the transform coefficient block context-adaptively using a global set of contexts .
167. Method for encoding a picture into a data stream, comprising:
encoding a transform coefficient block (92) representing a block (84) of the picture (12) into the data stream (14) using a scan pattern (94') which sequentially traverses transform coefficients (91) of the transform coefficient block by
entropy encoding quantization levels (106) of the transform coefficients of the transform coefficient block context-adaptively using, for each partition of partitions (120a,b,c) into which the transform coefficient block is subdivided, a set (110a,b,c) of contexts which is associated (126) with the respective partition (120),

wherein the scan pattern (94') sequentially traverses the transform coefficients (91) of the transform coefficient block (92) in a manner so that at least one transform coefficient (such as the hatched ones 91') of a first partition (e.g. 120a or 120c) is traversed between two transform coefficients of a second partition (e.g. 120b).
168. Method for decoding a picture from a data stream, comprising:
decoding a transform coefficient block (92) representing a block (84) of the picture (12) from the data stream (14) using a scan pattern (94') which sequentially traverses transform coefficients (91) of the transform coefficient block by
entropy decoding quantization levels (106) of the transform coefficients of the transform coefficient block context-adaptively using, for each partition of partitions into which the transform coefficient block is subdivided, a set (110a,b,c) of contexts which is associated (126) with the respective parti¬tion (120),
wherein the scan pattern (94') sequentially traverses the transform coefficients (91) of the transform coefficient block (92) in a manner so that at least one transform coefficient (such as the hatched ones 91') of a first partition is traversed between two transform coefficients of a second partition.
169. A computer program for implementing the method of at least one of claims 147 to 168,
170. A data stream obtainable by the method of at least one of claims 147, 149, 151, 153, 155, 157, 159, 161, 163, 165, 167.