extracted from wipo:
formulas and tables are not copied:
Extended Reference Intra-Picture Prediction

The present invention relates to video coding, in particular hybrid video coding comprising an intra-picture prediction. The present invention further relates to a video encoder, a video decoder and methods for video encoding, decoding, respectively.

H.265/HEVC is video codec which already provides tools for elevating or even enabling parallel processing at encoder and/or decoder. For instance, HEVC supports a sub-division of pictures into an array of tiles which are encoded independently from each other. Another concept supported by HEVC pertains to WPP, according to which CTU rows or CTU-lines of the pictures may be processed in parallel from left to right, i.e. in stripes, provided that some minimum CTU offset is obeyed in the processing of consecutive CTU lines. It would be favorable, however, to have a video codec at hand which supports parallel processing capabilities of video encoders and/or video decoders even more efficiently.

It is, thus, the object of the present invention to provide a video codec which enables a more efficient processing at encoder and/or decoder in terms of reference samples used for predicting a prediction block.

This object is achieved by the subject-matter of the independent claims of the present application.

According to an embodiment, a video encoder is configured to encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction. The video encoder is configured to use, for the intra-picture prediction, for encoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block. The video encoder is further configured to sequentially determine an availability or unavailability of each of the plurality of nearest reference samples and to substitute a nearest reference sample being determined as unavailable by a substitution sample. The video encoder is configured to use the substitution sample for the intra-picture prediction. This allows to use prediction concepts using nearest reference samples even if such samples are unavailable which may occur, for example, when

having a line or row of samples in a buffer/memory whilst not actually having a column of samples in the memory being thus unavailable.

According to an embodiment a video encoder is configured to encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction. The video encoder is configured to use, in the intra-picture prediction, for encoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block. The video encoder is further configured to filter at least a subset of the plurality of extended reference samples using a bilateral filter so as to obtain a plurality of filtered extended reference samples; and to use the plurality of filtered extended reference samples for the intra-picture prediction.

According to an embodiment, a video encoder is configured to encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction. The video encoder is configured to use, in the intra-picture prediction, for encoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block, wherein a plurality of nearest reference samples is arranged along a first picture direction of the prediction block and along a second picture direction of the prediction block; and to map at least a part of the nearest reference samples arranged along the second direction to extended reference samples being arranged along the first direction, such that the mapped reference samples exceed an extension of the prediction block along the first picture direction. The video encoder is configured to use the mapped extended reference samples for the prediction.

According to an embodiment, a video encoder is configured to encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction. The video encoder is configured to use, for the intra-picture prediction, for encoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, wherein the video encoder is configured to boundary filtering in a mode where no extended samples are used; and not to use boundary filtering when extended samples are used; or wherein the video encoder is configured to boundary filtering at least a subset of the plurality of nearest reference samples and not using boundary filtering for the extended samples.

According to an embodiment, a video encoder is configured to encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction. The video encoder is configured to determine, in the intra picture prediction, for encoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples. The video encoder is further configured to determine a prediction for the prediction block using the extended reference samples and to filter the extended reference samples so as to obtain a plurality of filtered extended reference samples; and to combine the prediction and the filtered extended reference samples so as to obtain a combined prediction for the prediction block.

According to an embodiment, a video encoder is configured to encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction. The video encoder is configured to use, for the intra-picture prediction, for encoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and/or a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples; to determine a first prediction for the prediction block using a first prediction mode of a set of prediction modes, the first set of prediction modes comprising prediction modes using the plurality of nearest reference samples in absence of the extended reference samples; and to determine a second prediction for the prediction block using a second prediction mode of a second set of prediction modes, the second set of prediction modes comprising a subset of the prediction modes of the first set, the subset being associated with the plurality of extended reference samples. The video encoder is configured to weightedly (wo;wi) combine the first prediction (p0(x,y)) and the second prediction (Pi(x,y)) so as to obtain a combined prediction (p(x,y)) as prediction for the prediction block in the coding data.

According to an embodiment, a video encoder is configured to encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction; to use, for the intra-picture prediction, for encoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and/or a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples; to use a prediction mode being one of a first set of prediction modes for predicting the prediction block using the nearest reference samples, e.g., in absence of extended reference samples; or being one of a second set of prediction modes for predicting the prediction block using the extended reference samples; wherein the second set of prediction modes is a subset of the first set of prediction modes; to signal a mode information (m) indicating the prediction mode used for predicting the prediction block; and to afterwards signal a parameter information (i) indicating a subset of the extended reference samples used for the prediction mode if the prediction mode is contained in the second set of prediction modes; and to skip signaling the parameter information when the used prediction mode is not contained in the second set of prediction modes, thereby allowing a conclusion at the decoder that a specific value of the parameter is chosen or selected ort determined, the predefined nature allowing skipping of the signaling, i.e., the absence of the signal is given an informative meaning. For example, the absence may indicate that the nearest reference samples have to be used.

According to an embodiment, a video encoder is configured to encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction; to use, for the intra-picture prediction, for encoding a prediction block of a picture, a plurality of reference samples comprising nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples; to use a prediction mode being one of a first set of prediction modes for predicting the prediction block using the nearest reference samples; or being one of a second set of prediction modes for predicting the prediction block using the extended reference samples; wherein the second set of prediction modes is a subset of the first set of prediction modes. The video encoder may use available reference data so as to generate the first set and/or the second set and/or may determine the set using information derived from the pictures. The second set being a subset of the first set includes the case that both sets are equal. The video encoder is configured to signal a parameter information indicating a subset of the plurality of reference samples used for the prediction mode, the subset of the plurality of reference samples comprising nearest reference samples only or extended reference samples; and to afterwards signal a mode information (m) indicating the prediction mode used for predicting the prediction block, wherein the mode information indicates a prediction mode from a subset of modes, the subset being restricted to a set of allowed prediction modes according to the parameter information (i). Based on an association of the references samples used, i.e., nearest or extended, an identification of the restricted set is possible as only those prediction modes apply which are associated with the reference samples indicated.

According to an embodiment, a video encoder is configured to encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction; to use, for the intra-picture prediction, for encoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and/or a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples; to determine a first prediction for the prediction block using a first prediction mode of a set of prediction modes, the first set of prediction modes comprising prediction modes using the plurality of nearest reference samples in absence of the extended reference samples; and to determine a second prediction for the prediction block using a second prediction mode of a second set of prediction modes, the second set of prediction modes comprising a subset of the prediction modes of the first set being associated with the plurality of extended reference samples. The video encoder is configured to combine the first prediction and the second prediction so as to obtain a combined prediction as prediction for the prediction block in the coding data.

According to an embodiment, a video encoder is configured to encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction; to use, in the intra-picture prediction, for encoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block; and to use the plurality of extended reference samples according to a predefined set of pluralities of extended reference samples. The pluralities of

extended reference samples, may be included, for example, in a list of area indices being identified by an identifier.

According to an embodiment, a video encoder is configured to encode, by block based predictive encoding a plurality of prediction blocks, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction; to use, for the intra-picture prediction, for encoding a prediction block of the plurality of prediction blocks, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block. The video encoder is configured to determine the extended reference samples so as to be at least partially a part of an adjacent prediction block of the plurality of prediction blocks, and to determine that the adjacent prediction block has not yet been predicted; and to signal information indicating the extended prediction samples associated to the prediction block and arranged in the adjacent prediction block as unavailable samples.

According to an embodiment, a video decoder is configured to decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction; to use, in the intra-picture prediction, for encoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block; to sequentially determine an availability or unavailability of each of the plurality of nearest reference samples; to substitute a nearest reference sample being determined as unavailable by a substitution sample; and to use the substitution sample for the intra-picture prediction.

According to an embodiment, a video decoder is configured to decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction; to use, in the intra-picture prediction, for decoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block; to filter at least a subset of the plurality of extended reference samples using a bilateral filter so as to obtain a plurality of filtered extended reference samples; and to use the plurality of filtered extended reference samples for the intra-picture prediction.

According to an embodiment, a video decoder is configured to decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction; to use, in the intra-picture prediction, for decoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block, wherein a plurality of nearest reference samples is arranged along a first picture direction of the prediction block and along a second picture direction of the prediction block; to map at least a part of the nearest reference samples arranged along the second direction to extended reference samples being arranged along the first direction, such that the mapped reference samples exceed an extension of the prediction block along the first picture direction; and to use the mapped extended reference samples for the prediction.

According to an embodiment, a video decoder is configured to decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction; to use, for the intra-picture prediction, for decoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples. The video decoder is configured to boundary filtering in a mode where no extended samples are used; and not to use boundary filtering when extended samples are used; or to boundary filtering at least a subset of the plurality of nearest reference samples and not using boundary filtering for the extended samples.

According to an embodiment, a video decoder is configured to decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction; to determine, in the intra-picture prediction, for decoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples; to determine a prediction for the prediction block using the extended reference samples; to filter the extended reference samples so as to obtain a plurality of filtered extended reference samples; and to combine the prediction and the filtered extended reference samples so as to obtain a combined prediction for the prediction block.

According to an embodiment, a video decoder is configured to decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction; to use, for the intra-picture prediction, for decoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and/or a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples; to determine a first prediction for the prediction block using a first prediction mode of a set of prediction modes, the first set of prediction modes comprising prediction modes using the plurality of nearest reference samples in absence of the extended reference samples; and to determine a second prediction for the prediction block using a second prediction mode of a second set of prediction modes, the second set of prediction modes comprising a subset of the prediction modes of the first set, the subset being associated with the plurality of extended reference samples. The video decoder is configured to weightedly combine the first prediction and the second prediction so as to obtain a combined prediction as prediction for the prediction block in the coding data.

According to an embodiment, a video decoder is configured to decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction; to use, for the intra-picture prediction, for decoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and/or a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples; to use a prediction mode being one of a first set of prediction modes for predicting the prediction block using the nearest reference samples; or being one of a second set of prediction modes for predicting the prediction block using the extended reference samples; wherein the second set of prediction modes is a subset of the first set of prediction modes; to receive a mode information (m) indicating the prediction mode used for predicting the prediction block; and to afterwards receive a parameter information (i) indicating a subset of the extended reference samples used for the prediction mode thereby indicating that the prediction mode is contained in the second set of prediction modes; and to determine that the used prediction mode is not contained in the second set of prediction modes when not receiving the parameter information and to determine a use of the nearest reference samples for the prediction.

According to an embodiment, a video decoder is configured to decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction; to use, for the intra-picture prediction, for decoding a prediction block of a picture, a plurality of reference samples comprising nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples; to use a prediction mode being one of a first set of prediction modes for predicting the prediction block using the nearest reference samples; or being one of a second set of prediction modes for predicting the prediction block using the extended reference samples; wherein the second set of prediction modes is a subset of the first set of prediction modes; to receive a parameter information (i) indicating a subset of the plurality of reference samples used for the prediction mode, the subset of the plurality of reference samples comprising nearest reference samples only or at least one extended reference sample; and to afterwards receive a mode information (m) indicating the prediction mode used for predicting the prediction block; wherein the mode information indicates a prediction mode from a subset of modes, the subset being restricted to a set of allowed prediction modes according to the parameter information (i).

According to an embodiment, a video decoder is configured to decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction; use, for the intra-picture prediction, for decoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and/or a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples; to determine a first prediction for the prediction block using a first prediction mode of a set of prediction modes, the first set of prediction modes comprising prediction modes using the plurality of nearest reference samples in absence of the extended reference samples; and to determine a second prediction for the prediction block using a second prediction mode of a second set of prediction modes, the second set of prediction modes comprising a subset of the prediction modes of the first set being associated with the plurality of extended reference samples. The video decoder is configured to combine the first prediction and the second prediction so as to obtain a combined prediction as prediction for the prediction block in the coding data.

According to an embodiment, a video decoder is configured to decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction; to use, in the intra-picture prediction, for decoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block; and to use the plurality of extended reference samples according to a predefined set of pluralities of extended reference samples.

According to an embodiment, a video decoder is configured to decode, by block based predictive decoding, pictures coded in coding data into a video, wherein for each picture a plurality of prediction blocks is decoded, wherein the block based predictive decoding comprises an intra picture prediction; and to use, for the intra-picture prediction, for decoding a prediction block of the plurality of prediction blocks, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block. The video decoder is configured to determine the extended reference samples so as to be at least partially a part of an adjacent prediction block of the plurality of prediction blocks, and to determine that the adjacent prediction block has not yet been predicted; and to receive information indicating the extended prediction samples associated to the prediction block and arranged in the adjacent prediction block as unavailable samples.

Further embodiments relate to methods for encoding and decoding a video and to a computer program product.

With respect to the aforementioned embodiments of the present application, it is noted that same may be combined so that more than one of the aforementioned embodiments such as all embodiments are implemented in a video codec concurrently.

Further, advantageous embodiments of the present application are the subject of dependent claims and preferred embodiments of the present application are described below with respect to the figures among which

Fig. 1 shows a schematic block diagram of a video encoder according to an embodiment, comprising a decoder according to an embodiment;

Fig. 2 shows a schematic flow chart of a method for encoding a video stream according to an embodiment;

Fig. 3 shows an example of directly neighboring (nearest) reference samples and extended reference samples used in embodiments;

Fig. 4a-4e show examples of five angular intra-picture prediction angles for a 4x2 block of prediction samples according to embodiments;

Fig. 4f shows a schematic diagram for illustrating an of a direction of an angular prediction used in embodiments;

Fig. 4g-4h show tables for illustrating example dependencies of a number of taps used in filters, the number being dependent from a block size of the prediction block and from the prediction mode;

Fig. 5a-5c show an embodiment in connection with an angular prediction using a definition of an angle parameter;

Fig. 6a-6c show a derivation of a vertical offset in connection with mapping reference samples according to embodiments;

Fig. 7a-7c show a derivation of a horizontal offset according to an embodiment;

Fig. 8 shows an embodiment for a diagonal top-left angle and a use of nearest reference samples according to an embodiment;

Fig. 9 shows an example projection of extended left reference samples as side reference next to the extended top reference samples as main reference in case of top-left diagonal prediction according to an embodiment;

Fig. 10 shows an example projection of nearest left reference samples as side reference next to the extended top reference samples according to an embodiment;

Fig. 1 1 shows an example truncated unary code for a specific set of reference areas according to an embodiment;

Fig. 12a-b show a schematic illustration of usable block sizes according to embodiments;

Fig. 13 shows a schematic diagram according to an embodiment of vertical angular prediction with an angle of 45 degree of a prediction block; and

Fig. 14a-b show an example of required nearest reference samples and extended reference samples in case of diagonal vertical intra-picture prediction and according to an embodiment.

Equal or equivalent elements or elements with equal or equivalent functionality are denoted in the following description by equal or equivalent reference numerals even if occurring in different figures.

In the following description, a plurality of details is set forth to provide a more thorough explanation of embodiments of the present invention. However, it will be apparent to those skilled in the art that embodiments of the present invention may be practiced without these specific details. In other instances, well known structures and devices are shown in block diagram form rather than in detail in order to avoid obscuring embodiments of the present invention. In addition, features of the different embodiments described hereinafter may be combined with each other, unless specifically noted otherwise.

In hybrid video coding, intra-picture prediction is used to encode an area of picture samples by generating a prediction signal from available neighboring samples, i.e. the reference samples. The prediction signal is subtracted from the original signal to get the residual signal. This residual signal or prediction error is further transformed, scaled, quantized and entropy coded as illustrated in Fig. 1 showing a schematic block diagram of a video encoder 1000 according to an embodiment being, for example, a hybrid video encoder with an intra-picture prediction block 1001 . The video encoder 1000 is configured to receive an input video signal 1002 comprising a plurality of pictures, a sequence of pictures forming a video. The video encoder 1000 comprises a block 1004 being configured to divide the signal 1002 into an area of samples, i.e., to form blocks from the input video signal 1002. A controller 1006 of the video encoder 1000 is configured to control the block 1004 and to control a decoder 1008 that may be a part of the encoder 1000. A decoder for receiving and decoding an output bitstream 1012 and a generated output video signal 1014, i.e., coding data, may be implemented accordingly. In particular, a transform, scaling and quantization block 1016 together with a block 1018 for motion estimation of the signal 1022 being the input video signal 1002 divided into blocks by the block 1004 may both provide information in terms of quantized transform coefficients and a motion information so as to enable entropy coding for the output bitstream 1012.

The quantized transformed coefficients are then scaled and inversed transformed to generate the reconstructed residual signal before potential in-loop filtering operations. This signal can be added to the prediction signal again to get the reconstruction that is also available at the decoder. The reconstructed signal can be used to predict succeeding samples in coding order within the same picture.

The intra-picture prediction is further detailed in Fig. 2. First, the reference samples used for the prediction are generated in a block 1042 based on the reconstructed samples. This stage also includes substituting neighboring samples that are not available, e.g. at picture, slice or tile boundaries. Second, in a block 1044 the reference samples can be filtered to eliminate discontinuities in the reference signal. Third, in a block 1046 the prediction samples are calculated using the reference samples according to the intra prediction mode. The prediction mode describes how the prediction signal is generated from the reference samples, e.g. by averaging them in the DC mode or by copying them along one prediction angle in an angular prediction mode. The encoder has to decide which intra prediction mode to select and the selected intra prediction mode is signaled in the bitstream by entropy coding to the decoder. At the decoder side, the intra prediction mode is extracted from the bitstream by entropy decoding. Fourth and possibly last, in a block 1048 the prediction samples can be filtered as well to smoothen the signal. In other words, Fig. 2 shows a flowchart of an intra-picture prediction process or method. In general, the correlation between samples in an image decreases with increasing distance. Hence directly neighboring samples are generally well suited as reference samples to predict an area of samples. However, there are cases where the directly neighboring reference samples represent an edge or an object in a uniform area (occlusion). In these cases, the correlation between the samples to predict (uniform or textured area) and the directly neighboring reference samples (edge) would be low. Extended reference intra-picture prediction solves this problem by incorporating more distant reference samples that are not directly neighboring. The concept of extending the nearest reference samples is known but several novel improvements for all parts of the intra-picture prediction process and signaling are defined in embodiments of the present invention and described in the following.

Extended reference intra-picture prediction allows to generate the prediction signal of a sample area using extended references samples. Extended reference samples are available reference samples that are not direct neighbors. In the following, improved reference sample generation, filtering, prediction and prediction filtering using extended reference samples according to embodiments are described in further detail. The special case of combining predictions using extended reference samples with prediction using directly neighboring samples or unfiltered reference samples is covered in afterwards. After that, various methods according to embodiments are described to improve prediction mode and extended reference area signaling for extended reference samples. Further, embodiment to facilitate parallel encoding with extended reference samples are described.

For reference sample generation, current video coding standards use directly neighboring samples to predict the current block. In literature, it was proposed to use multiple reference lines in addition to the nearest, directly neighboring samples. The additional reference lines to be used in intra-picture prediction are further referred to as extended reference samples in detailed in the following. After that, improved methods for substitution of non-available extended reference samples according to embodiments are described.

An example showing a nearest reference sample line and three extended reference sample lines of a 16x8 block to be predicted is illustrated in Fig. 3 showing an example of directly neighboring (nearest) reference samples 1062 and extended reference samples 1064i , 10642 and 10643.

The nearest reference samples 1062 and the extended reference samples 1064i, 10642 and 10643 are arranged adjacent to a prediction block 1066 to be predicted and being arranged along two directions of the picture, namely direction x and direction y being arranged perpendicular to direction x. Along the direction x, the prediction block comprises an extension W with samples ranging from 0 to W-1. Along the direction y, the prediction block comprises an extension H with samples ranging from 0 to H-1.

A reference area with index i may indicate a distance between the respective reference sample, i.e., the nearest reference sample having index i =0, i.e., being arranged directly adjacent, and extended reference samples being spaced from the prediction block 1066 at least by the nearest reference samples 1062. For example, the reference area index i may indicate an extension of a distance between the prediction block 1066 and the respective reference sample 1062 or 1064. By way of example, increasing parameter x along the direction x may be referred to as moving right and, on the contrary, reducing the x may be referred to as moving left.

Alternatively or in addition, reducing the index i along a negative direction y may be referred to as moving upwards or towards a top of the picture, wherein with an increase of parameter y, a movement downwards or towards a bottom of the picture may be indicated. Terms like top, bottom, left and right are used to simplify the understanding of the present invention. According to other embodiments, such terms may be changed, altered or substituted with any other directions without limiting the scope of the present embodiments. By way of example, reference samples 1062 and/or 1064 being arranged left from the prediction block, i.e., having x<0, may be referred to as left reference samples. Reference samples 1062 and/or 1064 being arranged so as to have y<0 may be referred to as top reference samples, assuming that an upper left edge of the prediction block 1066 has positions 0,0. Reference samples being identified as well as left reference samples and as top reference samples may be referred to as corner reference samples. Accordingly, reference samples exceeding the extension W along the x-direction may be referred to as right reference samples, wherein reference samples exceeding the extension H of the prediction block 1066 may be referred to as bottom reference samples.

In order to indicate which reference samples to use for prediction, each line of reference samples is associated with a reference area index i. The nearest reference samples are given an index i = 0, the next line of extended reference samples i = 1 and so on. Using the notation from Fig. 3, the top reference samples can be described by r(x, - 1 - i) with x ranging from 0 to M and the left reference samples can be described by r(- 1 - i, y) with y ranging from 0 to N. The parameters M for the horizontal extend and N for the vertical extend of the reference samples depend on the intra-picture prediction. In case top-right diagonal prediction is used as maximum angle clockwise for example as described in connection with Fig. 4e, the top reference samples need to extent M = W + H - l + i samples in horizontal direction. In case bottom-left diagonal prediction is used as maximum angle counter clockwise for example as described in Fig. 4a, the left reference samples need to extent M = H + W - 1 + i samples in vertical direction. As in Fig 3, l/Vdescribes the width and H the height of the prediction block.

A video encoder according to an embodiment, such as video encoder 1000 may be configured to encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction. The video encoder may use, in the intra-picture prediction, for encoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block. The video encoder may sequentially determine an availability or unavailability of each of the plurality of nearest reference samples and may substitute a nearest reference sample being determined as unavailable by a substitution sample. The video encoder may use the substitution sample for the intra-picture prediction.

For determining the availability or unavailability, the video encoder may check the samples sequentially according to a sequence, determine the substitution sample as a copy a last extended reference sample being determined as available in the sequence; and/or determine the substitution sample as a copy a next extended reference sample being determined as available in the sequence.

The video encoder may further determine the availability or unavailability sequentially according to a sequence and determine the substitution sample based on a combination of an extended reference sample being determined as available and being arranged in the sequence prior to the reference sample being determined as unavailable and of an extended reference sample being determined as available and being arranged in the sequence after the reference sample being determined as unavailable.

Alternatively or in addition, the video encoder may be configured to use, for the intra-picture prediction, for encoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples; and to determine an availability or unavailability of each of the plurality of extended reference samples. The video encoder may signal a use of the plurality of extended reference samples when a portion of available extended reference samples of the plurality of extended reference samples is larger than or equal a predetermined threshold; and skip signaling the use of the plurality of extended reference samples when the portion of available extended reference samples of the plurality of extended reference samples is below the predetermined threshold.

A respective decoder such as video decoder 1008 or a video decoder for generating a video stream again, may accordingly be configured to decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction; to use, in the intra-picture prediction, for encoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block; and to sequentially determine an availability or unavailability of each of the plurality of extended reference samples. The video decoder may substitute an extended reference sample being determined as unavailable by a substitution sample; and use the substitution sample for the intra-picture prediction.

The video decoder may further be configured to determine the availability or unavailability sequentially according to a sequence; determine the substitution sample as a copy a last extended reference sample being determined as available in the sequence; and/or determine the substitution sample as a copy a next extended reference sample being determined as available in the sequence.

Further, the video decoder may be configured to determine the availability or unavailability sequentially according to a sequence; and to determine the substitution sample based on a combination of an extended reference sample being determined as available and being arranged in the sequence prior to the reference sample being determined as unavailable and of an extended reference sample being determined as available and being arranged in the sequence after the reference sample being determined as unavailable.

The video decoder may alternatively or in addition be configured to use, for the intra-picture prediction, for decoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples; to determine an availability or unavailability of each of the plurality of extended reference samples; to signal receive information indicating a use of the plurality of extended reference samples when that a portion of available extended reference samples of the plurality of extended reference samples is larger than or equal a predetermined threshold and use of the plurality of extended reference samples; and to skip using the plurality of extended reference samples in absence of the information, i.e., when the portion of available extended reference samples of the plurality of extended reference samples is below the predetermined threshold.

When neighboring reference samples are not available, according to embodiments, an extended reference sample substitution may be performed. For example, the unavailable samples can be replaced by the closest neighboring sample that is available, a combination of the closest two or by a predetermined value in case there are no neighboring samples available, e.g. 2bitdepth~1. Reference samples are not available e.g. when they are located outside a picture, slice or tile boundary or when constrained intra prediction is used that disallows using samples from inter picture predicted areas as reference for intra-picture prediction areas.

For example, if the current block to be predicted is located at the left picture boundary the left and top-left corner reference samples are not available. In this case, the left and top-left corner reference samples are substituted by the first available top reference sample. When this first available top reference sample is the first one, i.e. r(0,— 1 - i), the substitution for nearest (i=0) and extended (i>0) reference samples can be formulated as follows:

r(— 1 - i, y) = r( 0, -1— t) with y = -1 - i.. M

r(x,— 1— i) = r(0,—1— i) with y =— 1— i.. M for i > 0

The parameter i may have any maximum value larger than 0 within the encode/decoder system, e.g., 1 , 2, 3, 4 or more such as 5 or more or 10 or more.

When constrained intra prediction is used, it can happen that one or more neighboring blocks are not available because they are coded using inter-picture prediction. For example, the left H samples r(-l - i, y) with y = 0. . H - 1 are inside an inter-picture predicted block and not available because constrained intra prediction is enabled.

In one embodiment, the availability checking process for each reference sample is done sequentially, e.g. from the bottom-left to the top-right reference samples or vice versa, the first sample that is not available along this direction is replaced by the last one that is available if there is one. If there is no sample available before, the unavailable samples are replaced by the next available sample. In the embodiment starting from bottom-right, the W bottom-right samples r(— 1— i, y ) with y = H.. W— 1 are available. Consequently, the left samples are replaced by as follows:

r(— 1 - t, y) = r(— 1 - i, M) with y = 0. . M - 1

In another embodiment, unavailable reference samples between available reference samples could be generated by linearly interpolating between the two nearest samples, one from each side.

In case it is determined that most of the extended reference area samples are not available, the use of extended reference samples does not bring any benefit compared to using the nearest reference samples. Hence the signaling of the reference area index can be saved and its signaling can be restricted to blocks where at least half of the extended reference samples are available.

A video encoder according to an embodiment such as video encoder 1000 may be configured to encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction; to use, in the intra-picture prediction, for encoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block; to filter at least a subset of the plurality of extended reference samples using a bilateral filter so as to obtain a plurality of filtered extended reference samples; and to use the plurality of filtered extended reference samples for the intra-picture prediction.

The video encoder according to this embodiment may be configured to combine the plurality of filtered extended reference samples with a plurality of unfiltered extended reference samples so as to obtain a plurality of combined reference values, wherein the video encoder is configured to use the plurality of combined reference values for the intra-picture prediction.

Alternatively or in addition, the video encoder may be configured to filter the plurality of extended reference samples using one of a 3-tap filter, a 5-tap filter and a 7-tap filter.

The video encoder may further be configured to select predict the prediction block using an angular prediction mode; wherein the 3-tap filter, a 5-tap filter and a 7-tap filter are configured as bilateral filters, wherein the video encoder is configured to select to use one of the 3-tap filter, the 5-tap filter and the 7-tap filter based on an angle used for the angular prediction, the angle arranged between a horizontal or a vertical direction of the angular prediction mode; and/or wherein the video decoder is configured to select to use one of the 3-tap filter, the 5-tap filter and the 7-tap filter based on a block size of the prediction block. As shown in Fig. 4f, an angle e may describe an angle of a direction of an angular prediction used for predicting the prediction block 1066 with respect to horizontal borders 1072 and/or vertical borders 1074 of the prediction block 1066 and measured towards a diagonal 1076 between the horizontal and vertical direction, i.e., the angle of the angular prediction is at most 45°. With increasing angle e an increased number of taps may be used in the filter. Alternatively or in addition, a block size may define a basis or dependency for selecting the filter.

A corresponding video decoder may be configured to decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction; to use, in the intra-picture prediction, for decoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block; to filter at least a subset of the plurality of extended reference samples using a bilateral filter so as to obtain a plurality of filtered extended reference samples; and to use the plurality of filtered extended reference samples for the intra-picture prediction.

The video decoder may further be configured to combine the plurality of filtered extended reference samples with a plurality of unfiltered extended reference samples so as to obtain a plurality of combined reference values, wherein the video decoder is configured to use the plurality of combined reference values for the intra-picture prediction.

Alternatively or in addition, the video decoder of may be configured to filter the plurality of extended reference samples using one of a 3-tap filter, a 5-tap filter and a 7-tap filter. As described for the encoder, the 3-tap filter, a 5-tap filter and a 7-tap filter are configured as bilateral filters, wherein the video decoder is configured to predict the prediction block using an angular prediction mode, and to select to use one of the 3-tap filter, the 5-tap filter and the 7-tap filter based on an angle used for the angular prediction, the angle arranged between a horizontal or a vertical direction of the angular prediction mode; and/or wherein the video decoder is configured to select to use one of the 3-tap filter, the 5-tap filter and the 7-tap filter based on a block size of the prediction block.

For example, instead of a bilateral filter, 3-tap FIR filters may be used. This may allow to filter only the nearest reference samples (although not with bilateral filter) and to leave the extended reference samples unfiltered.

For larger sample areas, discontinuities in the reference samples can occur that distort the prediction. The state of the art solution to this is to apply linear smoothing filters to the reference samples. In case of discontinuities, which can be detected for example by comparing to a predetermined threshold, strong smoothing can be applied. This typically generates the reference samples by interpolating between corner reference samples.

However, linear smoothing filters can also remove edge structure that needs to be preserved. Applying bilateral filters to the extended references samples according to an embodiment for reference sample filtering can prevent undesired smoothing of sharp edges. Since bilateral filtering is more efficient for larger blocks and intra prediction angles that deviate from the exact horizontal and exact vertical directions, the decision of whether to apply the filter and the length of the filter can depend on the block size and/or the prediction mode. One example design can incorporate dependencies as shown in Fig. 4g showing a dependency for block sizes smaller than 64x64 and larger than or equal to 64x64 with respect to WxH and Fig. 4h showing a different dependency for block sizes smaller than 64x64 and larger than or equal to 64x64 with respect to WxH. In the embodiment of Fig. 4g the intra-prediction mode may, for example, one of a planar mode, a DC mode, a near horizontal mode, a near vertical mode or a different angle of an angular mode. In the embodiment of Fig. 4h, additionally angles being identified as farer horizontal and farer vertical may be selected, for example, having a larger value of angle e shown in Fig. 4f when compared to near horizontal or near vertical. As may be seen, larger block sizes may result in a higher number of taps so as to facilitate filtering of the larger amount of data, wherein, additionally, an increase of e may also result in an increase of taps. According to Fig. 4h, an embodiment may apply a small 3-tap filter for near horizontal and near vertical modes and increases the filter length with increasing distance from horizontal and vertical direction. Although being illustrated as being dependent on both, the prediction mode and the block size, the selection of the filter or at least the number of taps may alternatively depend only on one of both and/or on additional parameters.

In another embodiment for reference sample filtering, an intra-picture prediction that uses filtered reference samples can be combined with unfiltered reference samples using a position-dependent weighting as described in connection with Position Depending Prediction Combination. In this case, the reference samples for the prediction that uses filtered references samples can use a different reference sample filtering than for the non-combined prediction. For example, the filtering can select among a set of 3-, 5- and 7-tap filters.

A video encoder according to an embodiment such as video encoder 1000 may be configured to encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction; to use, in the intra-picture prediction, for encoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block, wherein a plurality of nearest reference samples is arranged along a first picture direction of the prediction block and along a second picture direction of the prediction
CLAIMS

1. Video encoder configured to:

encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction;

use, in the intra-picture prediction, for encoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block;

sequentially determine an availability or unavailability of each of the plurality of extended reference samples;

substitute an extended reference sample being determined as unavailable by a substitution sample; and

use the substitution sample for the intra-picture prediction.

2. The video encoder of claim 1 , wherein the video encoder is configured to:

determine the availability or unavailability sequentially according to a sequence;

determine the substitution sample as a copy a last extended reference sample being determined as available in the sequence; and/or

determine the substitution sample as a copy a next extended reference sample being determined as available in the sequence.

3. The video encoder of claim 2, wherein the video encoder is configured to:

determine the availability or unavailability sequentially according to a sequence;

determine the substitution sample based on a combination of an extended reference sample being determined as available and being arranged in the sequence prior to the reference sample being determined as unavailable and of an extended reference sample being determined as available and being arranged in the sequence after the reference sample being determined as unavailable.

4. The video encoder of one of previous claims, wherein the video encoder is configured to:

use, for the intra-picture prediction, for encoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples

determine an availability or unavailability of each of the plurality of extended reference samples;

signal a use of the plurality of extended reference samples when a portion of available extended reference samples of the plurality of extended reference samples is larger than or equal a predetermined threshold; and

skip signaling the use of the plurality of extended reference samples when the portion of available extended reference samples of the plurality of extended reference samples is below the predetermined threshold.

5. Video encoder configured to:

encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction;

use, in the intra-picture prediction, for encoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block;

filtering at least a subset of the plurality of extended reference samples using a bilateral filter or a 3-tap FIR filter so as to obtain a plurality of filtered extended reference samples; and

use the plurality of filtered extended reference samples for the intra-picture prediction.

6. The video encoder of claim 5, wherein the video encoder is configured to filter the plurality of extended reference samples using one of a 3-tap filter, a 5-tap filter and a 7-tap filter.

7. The video encoder of claim 6, wherein the video encoder is configured to predict the prediction block using an angular prediction mode; wherein the 3-tap filter, a 5-tap filter and a 7-tap filter are configured as bilateral filters, wherein the video encoder is configured to select to use one of the 3-tap filter, the 5-tap filter and the 7-tap filter based on an angle used for the angular prediction, the angle arranged between a horizontal or a vertical direction of the angular prediction mode; and/or wherein the video encoder is configured to select to use one of the 3-tap filter, the 5-tap filter and the 7-tap filter based on a block size of the prediction block.

8. The video encoder of claim 7, wherein the video encoder is configured to select a filter with increasing taps for increasing angles with from to a horizontal direction or vertical direction towards a diagonal.

9. Video encoder configured to:

encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction;

use, in the intra-picture prediction, for encoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block, wherein a plurality of nearest reference samples is arranged along a first picture direction of the prediction block and along a second picture direction of the prediction block; map at least a part of the nearest reference samples arranged along the second direction to extended reference samples being arranged along the first direction, such that the mapped reference samples exceed an extension of the prediction block along the first picture direction; and

use the mapped extended reference samples for the prediction.

10. The video encoder of claim 9, wherein the video encoder is configured to map the portion of nearest reference samples according to a prediction mode used for predicting the prediction block.

11. The video encoder of claim 10, wherein the video encoder is configured to map the portion of nearest reference samples according to a direction used in the prediction mode for predicting the prediction block.

12. Video encoder configured to:

encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction;

use, for the intra-picture prediction, for encoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

wherein the video encoder is configured to boundary filtering in a mode where no extended samples are used; and not to use boundary filtering when extended samples are used; or

wherein the video encoder is configured to boundary filtering at least a subset of the plurality of nearest reference samples and not using boundary filtering for the extended samples.

13. Video encoder configured to:

encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction;

determining, in the intra-picture prediction, for encoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

determining a prediction for the prediction block using the extended reference samples;

filtering the extended reference samples so as to obtain a plurality of filtered extended reference samples; and

combining the prediction and the filtered extended reference samples so as to obtain a combined prediction for the prediction block.

14. The video encoder of claim 13, wherein the video encoder is configured to combine the prediction and extended reference samples being arranged in a major diagonal or minor diagonal of samples with respect to the prediction block.

15. The video encoder of claim 13 or 14, wherein the video encoder is configured to combine the prediction and the extended reference samples based on the determination rule:

wherein pc(x,y) denotes the combined prediction for coordinates x and y in the prediction block, p(x,y) denotes the prediction for coordinates x and y in the prediction block, c , c%, c'\ C2 are prediction weights, dx is a parameter set to 1 or 2 dependent on a size of the prediction block in dimension x, dy is a parameter set to 1 or 2 dependent on a size of the prediction block in dimension y, r(x,-1 -i) for i>0 is the extended top reference sample at horizontal position x, r(-1 -i,y) for i>0 is the extended left reference sample at vertical position y and r(-1 -i,-1 -i) for i>0 is an extended corner reference sample of the plurality of extended reference samples with respect to a boundary of the prediction block and b(x,y) denotes a normalization factor.

16. The video encoder of claim 15, wherein the normalization factor is determined based on the determination rule:

17. The video encoder of one of claims 13 to 16, wherein the video encoder is configured to filter the extended reference samples so as to obtain filtered extended reference samples (r(x,-1 -i), r(-1-i,y), r(-1 -i,-1 -i) for i>0) (combined) using one of a 3-tap filter, a 5-tap filter and a 7-tap filter and to use the filtered extended reference samples for the prediction.

18. The video encoder of one of claims 13 to 17, wherein the video encoder is configured to use a combination of extended corner reference samples of the prediction block and of extended reference samples being arranged in a corner region of reference samples (r(-1- ί,-1 -i)).

19. The video encoder of claim 18, wherein the video encoder is configured to obtain the combined prediction based on the determination rule:

wherein pc(x,y) denotes the combined prediction for coordinates x and y in the prediction block, p(x,y) denotes the prediction for coordinates x and y in the prediction block, c\, cv2, c’ are prediction weights, dx is a parameter set to 1 or 2 dependent on a size of the prediction block in dimension x, dy is a parameter set to 1 or 2 dependent on a size of the prediction block in dimension y, r(x,-1 -i) for i>0 is the extended top reference sample at horizontal position x, r(-1 -i,y) for i>0 is the extended left reference sample at vertical position

y and i>0 are the combined extended corner reference samples with

respect to a boundary of the prediction block and b(x,y) denotes a normalization factor.

20. The video encoder of one of claims 13 to 19, wherein the video encoder is configured to obtain the prediction p(x,y) based on an intra-picture prediction.

21 . The video encoder of claim 20, wherein the video encoder is configured to use only planar prediction as intra-picture prediction.

22. The video encoder of one of claims 13 to 21 , wherein the video encoder is configured, for each encoded video block, to determine a parameter set identifying the combination of the prediction and the filtered extended reference samples.

23. The video encoder of claim 22, wherein the video encoder is configured to determine the parameter set identifying the combination of the prediction and the filtered extended reference samples using a look-up table containing sets for different block sizes of the prediction block.

24. Video encoder configured to:

encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction;

use, for the intra-picture prediction, for encoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and/or a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

determine a first prediction for the prediction block using a first prediction mode of a set of prediction modes, the first set of prediction modes comprising prediction modes using the plurality of nearest reference samples in absence of the extended reference samples;

determining a second prediction for the prediction block using a second prediction mode of a second set of prediction modes, the second set of prediction modes comprising a subset of the prediction modes of the first set, the subset being associated with the plurality of extended reference samples,

wherein the video encoder is configured to weightedly (w0;wi) combine the first prediction (p0(x,y)) and the second prediction (Pi(x,y)) so as to obtain a combined prediction (p(x,y)) as prediction for the prediction block in the coding data.

25. The video encoder of claim 24, wherein the video encoder is configured to use the first prediction and the second prediction according to a predefined combination being a portion of possible combinations of enabled first prediction modes and enabled second prediction modes.

26. The video encoder of claim 24 or 25, wherein the video encoder is configured to signal either the first prediction mode or the second prediction mode whilst not signaling the other prediction mode.

27. The video encoder of one of claims 24 to 26, wherein the video encoder is configured to exclusively use a planar prediction mode as one of the first prediction mode and the second prediction mode.

28. The video encoder of one of claims 24 to 27, wherein the video encoder is configured to adapt a first weight applied to the first prediction in the combined prediction and a second weight applied to the second prediction in the combined prediction based on a block size of the prediction block; and/or

adapt the first weight based on the first prediction mode or the second weight based on the second prediction mode.

29 The video encoder of one of claims 24 to 28, wherein the video encoder is configured to adapt a first weight applied to the first prediction in the combined prediction and a second weight applied to the second prediction in the combined prediction based on a position.

30. The video encoder of claim 29, wherein the video encoder is configured to adapt the first weight and the second weight based on the determination rule

p(x, y) = w0(x, y) p0(x, y) + wJx, y) pJx, y)

wherein Wo(x,y) is the first weight based on the position x,y in the prediction block, w, is the second weight based on the position x,y in the prediction block, po(x,y) is the first prediction for the position x,y and p,(x,y) is the second prediction for the position x,y, and i indicates the extended reference samples to be used for the second prediction.

31. Video encoder configured to:

encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction;

use, for the intra-picture prediction, for encoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and/or a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

use a prediction mode being one of a first set of prediction modes for predicting the prediction block using the nearest reference samples; or being one of a second set of prediction modes for predicting the prediction block using the extended reference samples; wherein the second set of prediction modes is a subset of the first set of prediction modes;

signal a mode information (m) indicating the prediction mode used for predicting the prediction block; and

afterwards signal a parameter information (i) indicating a subset of the extended reference samples used for the prediction mode if the prediction mode is contained in the second set of prediction modes; and to skip signaling the parameter information when the used prediction mode is not contained in the second set of prediction modes.

32. The video encoder of claim 31 , wherein the video encoder is configured to skip signaling the parameter information, when the mode information indicates a DC mode or a planar mode.

33. Video encoder configured to:

encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction;

use, for the intra-picture prediction, for encoding a prediction block of a picture, a plurality of reference samples comprising nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

use a prediction mode being one of a first set of prediction modes for predicting the prediction block using the nearest reference samples; or being one of a second set of prediction modes for predicting the prediction block using the extended reference samples; wherein the second set of prediction modes is a subset of the first set of prediction modes;

signal a parameter information (i) indicating a subset of the plurality of reference samples used for the prediction mode, the subset of the plurality of reference samples comprising nearest reference samples only or extended reference samples;

afterwards signal a mode information (m) indicating the prediction mode used for predicting the prediction block, wherein the mode information indicates a prediction mode from a subset of modes, the subset being restricted to a set of allowed prediction modes according to the parameter information (i).

34. The video encoder of one of claims 31 to 33, wherein the extended reference samples in modes contained in the second set of prediction modes are used in addition to the nearest reference samples.

35. The video encoder of one of claims 31 to 34, wherein the first set of prediction modes describes prediction modes allowed for being used with the nearest reference samples, wherein the second set of prediction modes describes prediction modes of the first set of prediction modes being also allowed for being used with the extended reference samples.

36. The video encoder of one of claims 31 to 35, wherein a range of values of the parameter information covers a use of the nearest reference values only and a use of different subsets of extended reference values.

37. The video encoder of claim 36, wherein different portions of extended reference samples comprise a different distance to the prediction block.

38. The video encoder of claim 36 or 37, wherein the video encoder is configured to set the parameter information to one of a predefined number of values, the value indicating a number and a distance of reference samples used for the prediction mode.

39. The video encoder of one of claims 31 to 38, wherein the video encoder is configured to determine the first set of prediction modes and/or the second set of prediction modes based on a most probable mode coding.

40. Video encoder configured to:

encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction;

use, for the intra-picture prediction, for encoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and/or a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

determine a first prediction for the prediction block using a first prediction mode of a set of prediction modes, the first set of prediction modes comprising prediction modes using the plurality of nearest reference samples in absence of the extended reference samples;

determining a second prediction for the prediction block using a second prediction mode of a second set of prediction modes, the second set of prediction modes comprising a subset of the prediction modes of the first set being associated with the plurality of extended reference samples,

wherein the video encoder is configured to combine the first prediction and the second prediction so as to obtain a combined prediction as prediction for the prediction block in the coding data.

41. The video encoder of claim 40, wherein the prediction block is a first prediction block, wherein the video encoder is configured to predict a second prediction block of the video using a plurality of nearest reference samples associated with the second prediction block in absence of a plurality of extended reference samples associated with the second prediction block;

wherein the video encoder is configured to signal a combining information indicating that the prediction in the coding data is based on a combination of predictions or is based on a prediction using the plurality of extended reference samples in absence of the plurality of nearest reference samples.

42. The video encoder of claim 40 or 41 , wherein the video encoder is configured to use the first prediction mode as a predefined prediction mode.

43. The video encoder of claim 42, wherein the video encoder is configured to select the first prediction mode as being a same mode as the second prediction mode and using the nearest reference samples in absence of the extended reference samples; or to use the first prediction mode as preset prediction mode.

44. Video encoder configured to:

encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction;

use, in the intra-picture prediction, for encoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block; and

use the plurality of extended reference samples according to a predefined set of pluralities of extended reference samples.

45. The video encoder of claim 44, wherein the video encoder is configured to determine the predefined set of pluralities of extended reference samples such that pluralities in the set differ with respect to each other by a number or combination of lines and/or rows of samples of the picture to be used as reference samples.

46. The video encoder of claim 45, wherein the video encoder is configured to determine the predefined set of pluralities of extended reference samples based on a block size of the prediction block and/or a prediction mode used to predict the prediction block.

47. The video encoder of claim 45 or 46, wherein the video encoder is configured to determine the set of pluralities of extended reference samples for a block size of the prediction block being at least a predefined threshold and to skip signaling the set of pluralities of extended reference samples when the block size is below the predefined threshold value or to skip signaling the set of pluralities of extended reference samples based on a position of the set of pluralities of extended reference samples within a coding tree block.

48. The video encoder of claim 47, wherein the predefined threshold is a predefined number of samples along a width or height of the prediction block and/or a predefined aspect ratio of the prediction block along the width and the height.

49. The video encoder of claim 48, wherein the predefined number of samples is 8 and/or wherein the aspect ratio is greater than 1/4 and less than 4.

50. The video encoder of one of claims 44 to 49, wherein the video encoder is configured to predict the prediction block as a first prediction block using the plurality of extended reference samples and to predict a second prediction block not using extended reference samples, wherein the video encoder is configured to signal a predefined set of pluralities of extended reference samples associated with the first prediction block and to not signal a predefined set of extended reference samples in associated with the second prediction block.

51 . The video encoder of one of claims 44 to 50, wherein the video encoder is configured to signal, for each prediction block, information indicating one of a specific plurality of a set of pluralities of extended reference samples and a use of nearest reference samples only before information indicating the intra-picture prediction mode.

52. The video encoder of claim 51 , wherein the video encoder is configured to signal the information indicating the intra-picture prediction so as to thereby indicate prediction modes that are in accordance with the indicated specific plurality of the set of pluralities of extended reference samples or in accordance with the indicated use of nearest reference samples, only.

53. Video encoder configured to:

encode, by block based predictive encoding a plurality of prediction blocks, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra picture prediction;

use, for the intra-picture prediction, for encoding a prediction block of the plurality of prediction blocks, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block;

wherein the video encoder is configured to determine the extended reference samples so as to be at least partially a part of an adjacent prediction block of the plurality of prediction blocks, and to determine that the adjacent prediction block has not yet been predicted; and

to signal information indicating the extended prediction samples associated to the prediction block and arranged in the adjacent prediction block as unavailable samples.

54. The video encoder of claim 53, wherein the video encoder is configured to encode the pictures by parallel encoding lines of blocks according to a wavefront approach, and to predict the prediction block based on an angular prediction, wherein the video encoder is configured to determine the extended reference samples to be used for predicting the prediction block so as to be arranged in already predicted blocks of the picture.

55. The video encoder of claim 53 or 54, wherein the video encoder is configured to signal the extended prediction samples associated to the prediction block and arranged in the adjacent prediction block variantly as unavailable samples or available samples on a sequence level, a picture level or a slice level.

56. The video encoder of one of claims 53 to 55, wherein the video encoder is configured to signal the information indicating the extended prediction samples associated to the prediction block and arranged in the adjacent prediction block as unavailable samples together with information indicating a parallel coding of the picture.

57. The video encoder of one of previous claims, wherein the video encoder is configured to determine a list of most probable prediction modes based on a use of the plurality of nearest reference samples or the use of the plurality of extended reference samples for the prediction mode, wherein the video encoder is configured to substitute prediction modes restricted for the used reference samples by modes allowed for the prediction mode.

58. The video encoder of one of previous claims, wherein the video encoder is configured to apply prediction using extended reference samples to pictures comprising luma information only.

59. The video encoder of one of previous claims, wherein the video encoder is configured to generate extended reference samples exceeding a width and/or a height of nearest reference samples along a first and a second image direction by padding from a closest extended reference sample.

60. The video encoder of one of previous claims, wherein the video encoder is configured to predict the prediction using an angular prediction mode using only a subset of angles from possible angles of the angular prediction mode and to exclude unused angles from signaling encoding information to a decoder.

61 . The video encoder of one of previous claims, wherein the extended reference samples are arranged in at least 2 lines and rows in addition to nearest reference samples, preferably at least 3 lines and rows.

62. The video encoder of one of previous claims, wherein the video encoder is configured to use a specific plurality of a set of pluralities of extended reference samples for predicting the prediction block, wherein the video encoder is configured to select the specific plurality from the set of pluralities so as to comprise a lowest similarity of picture content when compared to a plurality of nearest reference samples extended by the set.

63. The video encoder of claim 62, wherein the video encoder is configured to signal a use of extended reference samples using a flag.

64. The video encoder of one of previous claims, wherein the video encoder is configured to selectively use the extended reference samples or nearest reference samples only, wherein the video encoder is configured to transform a residual obtained by predicting the prediction block using a first transformation procedure so as to obtain a first transformation result and to transform the first transformation result using a second transformation procedure so as to obtain a second transformation result when the extended reference samples are unused for predicting the prediction block.

65. The video encoder of claim 64, wherein the video encoder is configured to signal a use of the secondary transform; or to

implicitly signal a non-use of the secondary transform when indicating a use of the extended reference samples and to not include information relating to a result of a secondary transform in the coding data.

66. The video encoder of one of previous claims, wherein the prediction is a prediction for a residual signal to be used in combination with a quantized signal so as to decode the picture.

67. Video decoder configured to:

decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction;

use, in the intra-picture prediction, for encoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest

reference sample of the plurality of reference samples, directly neighboring the prediction block;

sequentially determine an availability or unavailability of each of the plurality of extended reference samples;

substitute an extended reference sample being determined as unavailable by a substitution sample; and

use the substitution sample for the intra-picture prediction.

68. The video decoder of claim 67, wherein the video decoder is configured to:

determine the availability or unavailability sequentially according to a sequence;

determine the substitution sample as a copy a last extended reference sample being determined as available in the sequence; and/or

determine the substitution sample as a copy a next extended reference sample being determined as available in the sequence.

69. The video decoder of claim 68, wherein the video decoder is configured to:

determine the availability or unavailability sequentially according to a sequence;

determine the substitution sample based on a combination of an extended reference sample being determined as available and being arranged in the sequence prior to the reference sample being determined as unavailable and of an extended reference sample being determined as available and being arranged in the sequence after the reference sample being determined as unavailable.

70. The video decoder of one of claims 67 to 69, wherein the video decoder is configured to:

use, for the intra-picture prediction, for decoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

determine an availability or unavailability of each of the plurality of extended reference samples;

receive information indicating that a portion of available extended reference samples of the plurality of extended reference samples is larger than or equal a predetermined threshold and use of the plurality of extended reference samples; and

skip using the plurality of extended reference samples in absence of the information.

71. Video decoder configured to:

decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction;

use, in the intra-picture prediction, for decoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block;

filtering at least a subset of the plurality of extended reference samples using a bilateral filter so as to obtain a plurality of filtered extended reference samples; and

use the plurality of filtered extended reference samples for the intra-picture prediction.

72. The video encoder of claim 71 , wherein the video decoder is configured to filter the plurality of extended reference samples using one of a 3-tap filter, a 5-tap filter and a 7-tap filter.

73. The video decoder of claim 72, wherein the 3-tap filter, a 5-tap filter and a 7-tap filter are configured as bilateral filters, wherein the video decoder is configured to predict the prediction block using an angular prediction mode, and to select to use one of the 3-tap

filter, the 5-tap filter and the 7-tap filter based on an angle used for the angular prediction, the angle arranged between a horizontal or a vertical direction of the angular prediction mode; and/or wherein the video decoder is configured to select to use one of the 3-tap filter, the 5-tap filter and the 7-tap filter based on a block size of the prediction block.

74. The video encoder of claim 73, wherein the video decoder is configured to select a filter with increasing taps for increasing angles from to a horizontal direction or vertical direction towards a diagonal.

75. Video decoder configured to:

decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction;

use, in the intra-picture prediction, for decoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block, wherein a plurality of nearest reference samples is arranged along a first picture direction of the prediction block and along a second picture direction of the prediction block;

map at least a part of the nearest reference samples arranged along the second direction to extended reference samples being arranged along the first direction, such that the mapped reference samples exceed an extension of the prediction block along the first picture direction; and

use the mapped extended reference samples for the prediction.

76. The video decoder of claim 75, wherein the video decoder is configured to map the portion of nearest reference samples according to a prediction mode used for predicting the prediction block.

77. The video decoder of claim 76, wherein the video decoder is configured to map the portion of nearest reference samples according to a direction used in the prediction mode for predicting the prediction block.

78. Video decoder configured to:

decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction;

use, for the intra-picture prediction, for decoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

wherein the video decoder is configured to boundary filtering in a mode where no extended samples are used; and not to use boundary filtering when extended samples are used; or

wherein the video decoder is configured to boundary filtering at least a subset of the plurality of nearest reference samples and not using boundary filtering for the extended samples.

79. Video decoder configured to:

decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction;

determining, in the intra-picture prediction, for decoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

determining a prediction for the prediction block using the extended reference samples;

filtering the extended reference samples so as to obtain a plurality of filtered extended reference samples; and

combining the prediction and the filtered extended reference samples so as to obtain a combined prediction for the prediction block.

80. The video decoder of claim 79, wherein the video decoder is configured to combine the prediction and extended reference samples being arranged in a major diagonal or minor diagonal of samples with respect to the prediction block.

81. The video decoder of claim 79 or 80, wherein the video decoder is configured to combine the prediction and the extended reference samples based on the determination rule:

wherein pc(x,y) denotes the combined prediction for coordinates x and y in the prediction block, p(x,y) denotes the prediction for coordinates x and y in the prediction block, ci’c2' ci’c2 are prediction weights, dx is a parameter set to 1 or 2 dependent on a size of the prediction block in dimension x, dy is a parameter set to 1 or 2 dependent on a size of the prediction block in dimension y, r(x,-1 -i) for i>0 is the extended top reference sample at horizontal position x, r(-1 -i,y) for i>0 is the extended left reference sample at vertical position y and r(-1 -i,-1-i) for i>0 is an extended corner reference sample of the plurality of extended reference samples with respect to a boundary of the prediction block and b(x,y) denotes a normalization factor.

82. The video decoder of claim 83, wherein the normalization factor is determined based on the determination rule:

b(x, y ) = 128

83. The video decoder of one of claims 79 to 82, wherein the video decoder is configured to filter the extended reference samples so as to obtain filtered extended reference samples (r(x,-1 -i), r(-1 -i,y), r(-1-i,-1 -i) for i>0) (combined) using one of a 3-tap filter, a 5-tap filter and a 7-tap filter and to use the filtered extended reference samples for the prediction.

84. The video decoder of one of claims 79 to 83, wherein the video decoder is configured to use a combination of extended corner reference samples of the prediction block and of extended reference samples being arranged in a corner region of reference samples (r(-1 - i,-i -0).

85. The video decoder of claim 84, wherein the video decoder is configured to obtain the combined prediction based on the determination rule:

wherein pc(x,y) denotes the combined prediction for coordinates x and y in the prediction block, p(x,y) denotes the prediction for coordinates x and y in the prediction block, ci’c > ci' , C are prediction weights, dx is a parameter set to 1 or 2 dependent on a size of the prediction block in dimension x, dy is a parameter set to 1 or 2 dependent on a size of the prediction block in dimension y, r(x,-1 -i) for i>0 is the extended top reference sample at horizontal position x, r(-1 -i,y) for i>0 is the extended left reference sample at vertical position y and
i>0 are the combined extended corner reference samples with respect to a boundary of the prediction block and b(x,y) denotes a normalization factor.

86. The video decoder of one of claims 79 to 85, wherein the video decoder is configured to obtain the prediction p(x,y) based on an intra-picture prediction.

87. The video decoder of claim 86, wherein the video decoder is configured to use only planar prediction as intra-picture prediction.

88. The video decoder of one of claims 79 to 87, wherein the video decoder is configured, for each decoded video block, to determine a parameter set identifying the combination of the prediction and the filtered extended reference samples.

89 The video decoder of claim 88, wherein the video decoder is configured to determine the parameter set identifying the combination of the prediction and the filtered extended reference samples using a look-up table containing sets for different block sizes of the prediction block.

90. Video decoder configured to:

decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction;

use, for the intra-picture prediction, for decoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and/or a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

determine a first prediction for the prediction block using a first prediction mode of a set of prediction modes, the first set of prediction modes comprising prediction modes using the plurality of nearest reference samples in absence of the extended reference samples;

determining a second prediction for the prediction block using a second prediction mode of a second set of prediction modes, the second set of prediction modes comprising a subset of the prediction modes of the first set, the subset being associated with the plurality of extended reference samples,

wherein the video decoder is configured to weightedly (wo;w,) combine the first prediction (po(x.y)) and the second prediction (pi(x,y)) so as to obtain a combined prediction (p(x,y)) as prediction for the prediction block in the coding data.

91 . The video decoder of claim 90, wherein the video decoder is configured to use the first prediction and the second prediction according to a predefined combination being a portion of possible combinations of enabled first prediction modes and enabled second prediction modes.

92. The video decoder of claim 90 or 91 , wherein the video decoder is configured to receive a signal indicating the second prediction mode whilst not receiving a signal indicating the first prediction mode and to derive the first prediction mode from the second prediction mode or a parameter information (i).

93. The video decoder of one of claims 90 to 92, wherein the video decoder is configured to exclusively use a planar prediction mode as one of the first prediction mode and the second prediction mode.

94. The video decoder of one of claims 90 to 93, wherein the video decoder is configured to adapt a first weight applied to the first prediction in the combined prediction and a second weight applied to the second prediction in the combined prediction based on a block size of the prediction block; and/or

adapt the first weight based on the first prediction mode or the second weight based on the second prediction mode.

95 The video decoder of one of claims 90 to 94, wherein the video decoder is configured to adapt a first weight applied to the first prediction in the combined prediction and a second weight applied to the second prediction in the combined prediction based on a position in the prediction block.

96. The video decoder of claim 95, wherein the video decoder is configured to adapt the first weight and the second weight based on the determination rule

p(x, y) = w0 (x, y) Po ( X , y) + Wi (x, y) * (x, y)

wherein w0(x,y) is the first weight based on the position x,y in the prediction block, w, is the second weight based on the position x,y in the prediction block, p0(x,y) is the first prediction for the position x,y and p,(x,y) is the second prediction for the position x,y, and i indicates the extended reference samples to be used for the second prediction.

97. Video decoder configured to:

decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction;

use, for the intra-picture prediction, for decoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and/or a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

use a prediction mode being one of a first set of prediction modes for predicting the prediction block using the nearest reference samples; or being one of a second set of prediction modes for predicting the prediction block using the extended reference samples; wherein the second set of prediction modes is a subset of the first set of prediction modes;

receive a mode information (m) indicating the prediction mode used for predicting the prediction block; and

afterwards receive a parameter information (i) indicating a subset of the extended reference samples used for the prediction mode thereby indicating that the prediction mode is contained in the second set of prediction modes; and to determine that the used prediction mode is not contained in the second set of prediction modes when not receiving the parameter information and to determine a use of the nearest reference samples for the prediction.

98. The video decoder of claim 97, wherein the video decoder is configured to determine the mode information as indicating a use of a DC mode or a planar mode when not receiving the parameter information.

99. Video decoder configured to:

decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction;

use, for the intra-picture prediction, for decoding a prediction block of a picture, a plurality of reference samples comprising nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

use a prediction mode being one of a first set of prediction modes for predicting the prediction block using the nearest reference samples; or being one of a second set of prediction modes for predicting the prediction block using the extended reference samples; wherein the second set of prediction modes is a subset of the first set of prediction modes;

receive a parameter information (i) indicating a subset of the plurality of reference samples used for the prediction mode, the subset of the plurality of reference samples comprising nearest reference samples only or at least one extended reference sample;

afterwards receive a mode information (m) indicating the prediction mode used for predicting the prediction block, wherein the mode information indicates a prediction mode from a subset of modes, the subset being restricted to a set of allowed prediction modes according to the parameter information (i).

100. The video decoder of claim 97 to 99, wherein the extended reference samples in modes contained in the second set of prediction modes are used in addition to the nearest reference samples.

101 . The video decoder of one of claims 97 to 100, wherein the first set of prediction modes describes prediction modes allowed for being used with the nearest reference samples, wherein the second set of prediction modes describes prediction modes of the first set of prediction modes being also allowed for being used with the extended reference samples.

102. The video decoder of one of claims 97 to 101 , wherein a range of values of the parameter information covers a use of the nearest reference values only and a use of different subsets of extended reference values.

103. The video decoder of claim 102, wherein different portions of extended reference samples comprise a different distance to the prediction block.

104. The video decoder of claim 102 or 103, wherein the video decoder is configured to set the parameter information to one of a predefined number of values, the value indicating a number and a distance of reference samples used for the prediction mode.

105. The video decoder of one of claims 97 to 104, wherein the video decoder is configured to determine the first set of prediction modes and/or the second set of prediction modes based on a most probable mode coding.

106. Video decoder configured to:

decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction;

use, for the intra-picture prediction, for decoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and/or a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

determine a first prediction for the prediction block using a first prediction mode of a set of prediction modes, the first set of prediction modes comprising prediction modes using the plurality of nearest reference samples in absence of the extended reference samples;

determining a second prediction for the prediction block using a second prediction mode of a second set of prediction modes, the second set of prediction modes comprising a subset of the prediction modes of the first set being associated with the plurality of extended reference samples,

wherein the video decoder is configured to combine the first prediction and the second prediction so as to obtain a combined prediction as prediction for the prediction block in the coding data.

107. The video decoder of claim 106, wherein the prediction block is a first prediction block, wherein the video decoder is configured to predict a second prediction block of the video using a plurality of nearest reference samples associated with the second prediction block in absence of a plurality of extended reference samples associated with the second prediction block;

wherein the video decoder is configured to receive a combining information indicating that the prediction in the coding data is based on a combination of predictions or is based on a prediction using the plurality of extended reference samples in absence of the plurality of nearest reference samples and do decode the coding data accordingly.

108. The video decoder of claim 106 or 107, wherein the video decoder is configured to use the first prediction mode as a predefined prediction mode.

109. The video decoder of claim 108, wherein the video decoder is configured to select the first prediction mode as being a same mode as the second prediction mode and using the nearest reference samples in absence of the extended reference samples; or to use the first prediction mode as preset prediction mode.

1 10. Video decoder configured to:

decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction;

use, in the intra-picture prediction, for decoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block; and

use the plurality of extended reference samples according to a predefined set of pluralities of extended reference samples.

1 1 1. The video decoder of claim 1 10, wherein the video decoder is configured to determine the predefined set of pluralities of extended reference samples such that pluralities in the set differ with respect to each other by a number or combination of lines and/or rows of samples of the picture to be used as reference samples.

1 12. The video decoder of claim 1 11 , wherein the video decoder is configured to determine the predefined set of pluralities of extended reference samples based on a block size of the prediction block and/or a prediction mode used to predict the prediction block.

1 13. The video decoder of claim 1 1 1 or 112, wherein the video decoder is configured to determine the set of pluralities of extended reference samples for a block size of the prediction block being at least a predefined threshold and to skip using the set of pluralities of extended reference samples when the block size is below the predefined threshold value.

1 14. The video decoder of claim 1 13, wherein the predefined threshold is a predefined number of samples along a width or height of the prediction block and/or a predefined aspect ratio of the prediction block along the width and the height.

115. The video decoder of claim 1 14, wherein the predefined number of samples is 8 and/or wherein the aspect ratio is greater than 1/4 and at less than 4.

116. The video decoder of one of claims 1 10 to 1 15, wherein the video decoder is configured to predict the prediction block as a first prediction block using the plurality of extended reference samples and to predict a second prediction block not using extended reference samples, wherein the video decoder is configured to receive information indicating a predefined set of pluralities of extended reference samples associated with the first prediction block and to determine a predefined set of extended reference samples in associated with the second prediction block in absence of a respective signal.

1 17. The video decoder of one of claims 1 10 to 1 16, wherein the video decoder is configured to receive, for each prediction block, information indicating a one of a specific plurality of a set of pluralities of extended reference samples and a use of nearest reference samples only before information indicating the intra-picture prediction mode.

1 18. The video decoder of claim 1 17, wherein the video decoder is configured to receive the information indicating the intra-picture prediction so as to thereby indicate prediction modes that are in accordance with the indicated specific plurality of the set of pluralities of extended reference samples or in accordance with the indicated use of nearest reference samples, only.

1 19. Video decoder configured to:

decode, by block based predictive decoding, pictures coded in coding data into a video, wherein for each picture a plurality of prediction blocks is decoded, wherein the block based predictive decoding comprises an intra-picture prediction;

use, for the intra-picture prediction, for decoding a prediction block of the plurality of prediction blocks, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block;

wherein the video decoder is configured to determine the extended reference samples so as to be at least partially a part of an adjacent prediction block of the plurality of prediction blocks, and to determine that the adjacent prediction block has not yet been predicted; and

to receive information indicating the extended prediction samples associated to the prediction block and arranged in the adjacent prediction block as unavailable samples.

120. The video decoder of claim 1 19, wherein the video decoder is configured to decode the pictures by parallel decoding lines of blocks according to a wavefront approach, and to predict the prediction block based on an angular prediction, wherein the video decoder is configured to determine the extended reference samples to be used for predicting the prediction block so as to be arranged in already predicted blocks of the picture.

121. The video decoder of claim 1 19 or 120, wherein the video decoder is configured to receive information indicating the extended prediction samples associated to the prediction block and arranged in the adjacent prediction block variantly as unavailable samples or available samples on a sequence level, a picture level or a slice level.

122. The video decoder of one of claims 1 19 to 121 , wherein the video decoder is configured to receive the information indicating the extended prediction samples associated to the prediction block and arranged in the adjacent prediction block as unavailable samples together with information indicating a parallel decoding of the picture.

123. The video decoder of one of claims 68 to 122, wherein the video decoder is configured to determine a list of most probable prediction modes based on a use of the plurality of nearest reference samples or the use of the plurality of extended reference samples for the prediction mode, wherein the video decoder is configured to substitute prediction modes restricted for the used reference samples by modes allowed for the prediction mode.

124. The video decoder of one of claims 68 to 123, wherein the video decoder is configured to apply prediction using extended reference samples to pictures comprising luma information only.

125. The video decoder of one of claims 68 to 124, wherein the video decoder is configured to generate extended reference samples exceeding a width and/or a height of nearest reference samples along a first and a second image direction by padding from a closest extended reference sample.

126. The video decoder of one of claims 68 to 125, wherein the video decoder is configured to predict the prediction using an angular prediction mode using only a subset of angles from possible angles of the angular prediction mode and to exclude unused angles from the prediction.

127. The video decoder of one of claims 68 to 126, wherein the extended reference samples are arranged in at least 2 lines and rows in addition to nearest reference samples, preferably at least 3 lines and rows.

128. The video decoder of one of claims 68 to 127, wherein the video decoder is configured to use a specific plurality of a set of pluralities of extended reference samples for predicting the prediction block, wherein the video decoder is configured to select the specific plurality from the set of pluralities so as to comprise a lowest similarity of picture content when compared to a plurality of nearest reference samples extended by the set.

129. The video decoder of claim 128, wherein the video decoder is configured to receive information indicating a use of extended reference samples by a flag.

130. The video decoder of one of claims 68 to 129, wherein the video decoder is configured to selectively use the extended reference samples or nearest reference samples only, wherein the video decoder is configured to transform a residual obtained by predicting the prediction block using a first transformation procedure so as to obtain a first transformation result and to transform the first transformation result using a second transformation procedure so as to obtain a second transformation result when the extended reference samples are unused for predicting the prediction block.

131 . The video decoder of claim 130, wherein the video decoder is configured to receive information indicating a use of the secondary transform; or to

derive a non-use of the secondary transform when indicating a use of the extended reference samples and to not receive information relating to a result of a secondary transform in the coding data.

132. The video decoder of one of claims 68 to 131 , wherein the prediction is a prediction for a residual signal to be used in combination with a quantized signal so as to decode the picture.

133. Method for encoding a video, the method comprising:

encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction;

use, in the intra-picture prediction, for encoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block;

sequentially determine an availability or unavailability of each of the plurality of extended reference samples;

substitute an extended reference sample being determined as unavailable by a substitution sample; and

use the substitution sample for the intra-picture prediction.

134. Method for encoding a video, the method comprising:

encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction;

use, in the intra-picture prediction, for encoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block;

filtering at least a subset of the plurality of extended reference samples using a bilateral filter so as to obtain a plurality of filtered extended reference samples; and

use the plurality of filtered extended reference samples for the intra-picture prediction.

135. Method for encoding a video, the method comprising:

encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction;

use, in the intra-picture prediction, for encoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block, wherein a plurality of nearest reference samples is arranged along a first picture direction of the prediction block and along a second picture direction of the prediction block;

map at least a part of the nearest reference samples arranged along the second direction to extended reference samples being arranged along the first direction, such that the mapped reference samples exceed an extension of the prediction block along the first picture direction; and

use the mapped extended reference samples for the prediction.

136. Method for encoding a video, the method comprising:

encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction;

use, for the intra-picture prediction, for encoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

boundary filtering in a mode where no extended samples are used; and not to use boundary filtering when extended samples are used; or

boundary filtering at least a subset of the plurality of nearest reference samples and not using boundary filtering for the extended samples.

137. Method for encoding a video, the method comprising:

encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction;

determining, in the intra-picture prediction, for encoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

determining a prediction for the prediction block using the extended reference samples;

filtering the extended reference samples so as to obtain a plurality of filtered extended reference samples; and

combining the prediction and the filtered extended reference samples so as to obtain a combined prediction for the prediction block.

138. Method for encoding a video, the method comprising:

encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction;

use, for the intra-picture prediction, for encoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and/or a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

determine a first prediction for the prediction block using a first prediction mode of a set of prediction modes, the first set of prediction modes comprising prediction modes using the plurality of nearest reference samples in absence of the extended reference samples;

determining a second prediction for the prediction block using a second prediction mode of a second set of prediction modes, the second set of prediction modes comprising a subset of the prediction modes of the first set, the subset being associated with the plurality of extended reference samples,

to weightedly (w0;wi) combine the first prediction (po(x,y)) and the second prediction (pi(x,y)) so as to obtain a combined prediction (p(x,y)) as prediction for the prediction block in the coding data.

139. Method for encoding a video, the method comprising:

encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction;

use, for the intra-picture prediction, for encoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and/or a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

use a prediction mode being one of a first set of prediction modes for predicting the prediction block using the nearest reference samples; or being one of a second set of prediction modes for predicting the prediction block using the extended reference samples; wherein the second set of prediction modes is a subset of the first set of prediction modes;

signal a mode information (m) indicating the prediction mode used for predicting the prediction block; and

afterwards signal a parameter information (i) indicating a subset of the extended reference samples used for the prediction mode if the prediction mode is contained in the second set of prediction modes; and to skip signaling the parameter information when the used prediction mode is not contained in the second set of prediction modes.

140. Method for encoding a video, the method comprising:

encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction;

use, for the intra-picture prediction, for encoding a prediction block of a picture, a plurality of reference samples comprising nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

use a prediction mode being one of a first set of prediction modes for predicting the prediction block using the nearest reference samples; or being one of a second set of prediction modes for predicting the prediction block using the extended reference samples; wherein the second set of prediction modes is a subset of the first set of prediction modes;

signal a parameter information (i) indicating a subset of the plurality of reference samples used for the prediction mode, the subset of the plurality of reference samples comprising nearest reference samples only or extended reference samples;

afterwards signal a mode information (m) indicating the prediction mode used for predicting the prediction block, wherein the mode information indicates a prediction mode from a subset of modes, the subset being restricted to a set of allowed prediction modes according to the parameter information (i).

141 . Method for encoding a video, the method comprising:

encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction;

use, for the intra-picture prediction, for encoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and/or a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

determine a first prediction for the prediction block using a first prediction mode of a set of prediction modes, the first set of prediction modes comprising prediction modes using the plurality of nearest reference samples in absence of the extended reference samples;

determining a second prediction for the prediction block using a second prediction mode of a second set of prediction modes, the second set of prediction modes comprising a subset of the prediction modes of the first set being associated with the plurality of extended reference samples,

combine the first prediction and the second prediction so as to obtain a combined prediction as prediction for the prediction block in the coding data.

142. Method for encoding a video, the method comprising:

encode, by block based predictive encoding, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra-picture prediction;

use, in the intra-picture prediction, for encoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality

of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block; and

use the plurality of extended reference samples according to a predefined set of pluralities of extended reference samples.

143. Method for encoding a video, the method comprising:

encode, by block based predictive encoding a plurality of prediction blocks, pictures of a video into coding data, wherein the block based predictive encoding comprises an intra picture prediction;

use, for the intra-picture prediction, for encoding a prediction block of the plurality of prediction blocks, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block;

determine the extended reference samples so as to be at least partially a part of an adjacent prediction block of the plurality of prediction blocks, and to determine that the adjacent prediction block has not yet been predicted; and

to signal information indicating the extended prediction samples associated to the prediction block and arranged in the adjacent prediction block as unavailable samples.

144. Method for decoding a video, the method comprising:

decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction;

use, in the intra-picture prediction, for encoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest

reference sample of the plurality of reference samples, directly neighboring the prediction block;

sequentially determine an availability or unavailability of each of the plurality of extended reference samples;

substitute an extended reference sample being determined as unavailable by a substitution sample; and

use the substitution sample for the intra-picture prediction.

145. Method for decoding a video, the method comprising:

decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction;

use, in the intra-picture prediction, for decoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block;

filtering at least a subset of the plurality of extended reference samples using a bilateral filter so as to obtain a plurality of filtered extended reference samples; and

use the plurality of filtered extended reference samples for the intra-picture prediction.

146. Method for decoding a video, the method comprising:

decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction;

use, in the intra-picture prediction, for decoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest

reference sample of the plurality of reference samples, directly neighboring the prediction block, wherein a plurality of nearest reference samples is arranged along a first picture direction of the prediction block and along a second picture direction of the prediction block;

map at least a part of the nearest reference samples arranged along the second direction to extended reference samples being arranged along the first direction, such that the mapped reference samples exceed an extension of the prediction block along the first picture direction; and

use the mapped extended reference samples for the prediction.

147. Method for decoding a video, the method comprising:

decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction;

use, for the intra-picture prediction, for decoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

boundary filtering in a mode where no extended samples are used; and not to use boundary filtering when extended samples are used; or

boundary filtering at least a subset of the plurality of nearest reference samples and not using boundary filtering for the extended samples.

148. Method for decoding a video, the method comprising:

decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction;

determining, in the intra-picture prediction, for decoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

determining a prediction for the prediction block using the extended reference samples; and

filtering the extended reference samples so as to obtain a plurality of filtered extended reference samples; and

combining the prediction and the filtered extended reference samples so as to obtain a combined prediction for the prediction block.

149. Method for decoding a video, the method comprising:

decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction;

use, for the intra-picture prediction, for decoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and/or a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

determine a first prediction for the prediction block using a first prediction mode of a set of prediction modes, the first set of prediction modes comprising prediction modes using the plurality of nearest reference samples in absence of the extended reference samples;

determining a second prediction for the prediction block using a second prediction mode of a second set of prediction modes, the second set of prediction modes comprising a subset of the prediction modes of the first set, the subset being associated with the plurality of extended reference samples,

weightedly (w0;wi) combine the first prediction (po(x,y)) and the second prediction (pi(x,y)) so as to obtain a combined prediction (p(x,y)) as prediction for the prediction block in the coding data.

150. Method for decoding a video, the method comprising:

decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction;

use, for the intra-picture prediction, for decoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and/or a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

use a prediction mode being one of a first set of prediction modes for predicting the prediction block using the nearest reference samples; or being one of a second set of prediction modes for predicting the prediction block using the extended reference samples; wherein the second set of prediction modes is a subset of the first set of prediction modes;

receive a mode information (m) indicating the prediction mode used for predicting the prediction block; and

afterwards receive a parameter information (i) indicating a subset of the extended reference samples used for the prediction mode thereby indicating that the prediction mode is contained in the second set of prediction modes; and determine that the used prediction mode is not contained in the second set of prediction modes when not receiving the parameter information and to determine a use of the nearest reference samples for the prediction.

151 . Method for decoding a video, the method comprising:

decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction;

use, for the intra-picture prediction, for decoding a prediction block of a picture, a plurality of reference samples comprising nearest reference samples of the picture directly neighboring the prediction block and a plurality of extended reference samples, each

extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

use a prediction mode being one of a first set of prediction modes for predicting the prediction block using the nearest reference samples; or being one of a second set of prediction modes for predicting the prediction block using the extended reference samples; wherein the second set of prediction modes is a subset of the first set of prediction modes;

receive a parameter information (i) indicating a subset of the plurality of reference samples used for the prediction mode, the subset of the plurality of reference samples comprising nearest reference samples only or at least one extended reference samples;

afterwards receive a mode information (m) indicating the prediction mode used for predicting the prediction block, wherein the mode information indicates a prediction mode from a subset of modes, the subset being restricted to a set of allowed prediction modes according to the parameter information (i).

152. Method for decoding a video, the method comprising:

decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction;

use, for the intra-picture prediction, for decoding a prediction block of a picture, a plurality of nearest reference samples of the picture directly neighboring the prediction block and/or a plurality of extended reference samples, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples;

determine a first prediction for the prediction block using a first prediction mode of a set of prediction modes, the first set of prediction modes comprising prediction modes using the plurality of nearest reference samples in absence of the extended reference samples;

determining a second prediction for the prediction block using a second prediction mode of a second set of prediction modes, the second set of prediction modes comprising a subset

of the prediction modes of the first set being associated with the plurality of extended reference samples,

combine the first prediction and the second prediction so as to obtain a combined prediction as prediction for the prediction block in the coding data.

153. Method for decoding a video, the method comprising:

decode, by block based predictive decoding, pictures coded in coding data into a video, wherein the block based predictive decoding comprises an intra-picture prediction;

use, in the intra-picture prediction, for decoding a prediction block of a picture, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block; and

use the plurality of extended reference samples according to a predefined set of pluralities of extended reference samples.

154. Method for decoding a video, the method comprising:

decode, by block based predictive decoding, pictures coded in coding data into a video, wherein for each picture a plurality of prediction blocks is decoded, wherein the block based predictive decoding comprises an intra-picture prediction;

use, for the intra-picture prediction, for decoding a prediction block of the plurality of prediction blocks, a plurality of extended reference samples of the picture, each extended reference sample of the plurality of extended reference samples separated from the prediction block at least by one nearest reference sample of the plurality of reference samples, directly neighboring the prediction block;

determine the extended reference samples so as to be at least partially a part of an adjacent prediction block of the plurality of prediction blocks, and to determine that the adjacent prediction block has not yet been predicted; and

receive information indicating the extended prediction samples associated to the prediction block and arranged in the adjacent prediction block as unavailable samples.

155. Non-transitory storage medium having stored thereon a computer program having a program code for performing, when running on a computer, a method according to one of claims 133-154.