Abstract: At least a method and an apparatus are presented for improving parallelization for wavefront parallel encoding and decoding of luma and chroma components of a vide picture. For example, a luma component and a chroma component of a video picture are independently subdivided into respectively a plurality of luma coding units and a plurality of chroma coding units. A context-based adaptive binary coding context variable is propagated from a previous row to a current row of the independently subdivided plurality of luma coding units, and a context-based adaptive binary coding context variable is propagated from a previous row to a current row of the independently subdivided plurality of chroma coding units. The video picture is encoded or decoded using the propagations to provide the wavefront parallel processing.

Abstract: At least a method and an apparatus are presented for efficiently encoding or decoding video. For example, for a block being encoded, a set of predictor candidates is determined. For a current potential predictor candidate in a set of potential predictor candidates, it is determined that the current potential predictor candidate is different from any predictor candidate in a subset of predictor candidates from the set of predictor candidates and in response the current potential predictor candidate is added to the set of predictor candidates. Thus, the set of predictor candidates is pruned with partial comparison in the set. The block is encoded or decoded based on a predictor candidate from pruned set of predictor candidates.

Abstract: At least a method and an apparatus are presented for efficiently encoding or decoding video. For example, a plurality of motion vectors are obtained for used in determining motion information for a block using affine modeling, wherein at least one of the plurality of motion vectors is determined based on a block size of the block. The video is then encoded or decoded based on the plurality of motion vectors.

Abstract: When dependent scalar quantization is used, the choice of the quantizer depends on the decoding of the preceding transform coefficient, and the entropy decoding of a transform coefficient depends on quantizer choice. To maintain high throughput in hardware implementations for transform coefficient entropy coding, several decision schemes of the scaler quantizer are proposed. In one implementation, the state transition and the context model selection are based on only regular coded bins. For example, the state transition can be based on the sum of the SIG, gt1 and gt2 flags, the exclusive-or function of the SIG, gt1 and gt2 flags, or based on only the gt1 or gt2 flag. When a block of transform coefficients is coded, the regular mode bins can be coded first in one or more scan passes, and the remaining bypass coded bins are grouped together in another one or more scan passes.

Abstract: At least a method and an apparatus are presented for improving parallelization for wavefront parallel encoding and decoding of luma and chroma components of a vide picture. For example, a luma component and a chroma component of a video picture are independently subdivided into respectively a plurality of luma coding units and a plurality of chroma coding units. A context-based adaptive binary coding context variable is propagated from a previous row to a current row of the independently subdivided plurality of luma coding units, and a context-based adaptive binary coding context variable is propagated from a previous row to a current row of the independently subdivided plurality of chroma coding units. The video picture is encoded or decoded using the propagations to provide the wavefront parallel processing.

Abstract: A method for video decoding is disclosed. A directional intra prediction mode is decoded for a block of a picture, the directional intra prediction mode having a direction. Based on the directional intra prediction mode, a first predictor and a second predictor for a sample in the current block are accessed, the first and second predictors being on a line at least approximating the direction. A sample value of the sample is predicted by interpolation using the first and second predictors, responsive to a difference between the second and first predictors, wherein the difference is scaled by at least a ratio that is based on a location of the sample in the block, and wherein a denominator of the ratio is a power of two regardless of the location of the sample. The sample of the block is reconstructed based on the predicted sample value.

Abstract: Apparatus and methods for encoding and decoding video data having improved quantization parameter prediction are presented and can include using a combination of quantization parameter prediction values obtained from respective ones of a plurality of quantization parameter prediction methods to encode or decode the video data.

Abstract: A significance-coefficient flag indicates whether a given quantized transform coefficient is equal to zero or not. To encode the significant-coefficient flags, context-based entropy coding can be used. To adapt to the characteristics of a video sequence, the context model is selected based on the statistics of the transform coefficients. In one embodiment, the non-zero probabilities of transform coefficients are compared to different thresholds to divide a transform block into several context regions, where all coefficients in a context region use the same set of context models. In another embodiment, the transform block is first divided into several context regions based on the positions of the transform coefficients, and the non-zero probabilities of transform coefficients are compared with a threshold to divide each context region into two sub-regions, where all coefficients in a sub-region share the same set of context models.

Abstract: A method for determining a luminance value used to process color samples in a decoder or encoder is provided comprising determining (33, 44) a luminance sample associated with a chroma sample position in a common space; and applying (34, 492) the determined luminance sample in a process that depends on luminance that is being applied to the chroma sample.

Abstract: The present disclosure generally relates to a method and device for encoding an image block, characterized in that it comprises: obtaining (101) a low-spatial-frequency version (Llƒ) of a luminance component of the image block, said the obtained luminance component of the image block; obtaining a quantized luminance component (Llƒ,Q) of the image block by quantizing (102) the obtained luminance component (Llƒ) of the image block; obtaining (103) a differential luminance component (Lr) by calculating the difference between the luminance component (L) of the image block and either the quantized luminance component (Llƒ,Q) of the image block or a decoded version (Llƒ,Q) of the encoded quantized luminance component of the image block; encoding (104) the quantized luminance component (Llƒ,Q of the image block using at least one frequency coefficient of a set of frequency coefficients which is usually obtained from a block-based spatial-to-frequency transform for encoding the luminance component of the image block;

Abstract: A method and an apparatus for encoding a video are disclosed. For at least one block from a picture of said video, at least one first rate-distortion cost for coding said block according to a first splitting mode of said block is determined (402, 408). It is then determined (404) if coding said block according to said first splitting mode of said block satisfies a criterion. If so, a second rate-distortion cost for coding said block according to at least one asymmetric splitting mode is determined (408), wherein said asymmetric splitting mode corresponds to splitting said block horizontally, or vertically, into two asymmetric subblocks. A best splitting mode for said block is determined (411) according to at least said first rate-distortion cost and said second rate-distortion cost, and the block is encoded (412) according to said best splitting mode.

Abstract: A method and device for encoding or decoding a picture block having a luminance component. The method includes obtaining a luminance residual block (Lr) by subtracting a first representation (Ll, LlD) of an average value of the luminance component calculated from the luminance component, obtaining a second representation (ƒ(Ll), ƒ(Ll)D) of the average value by applying a transfer function to the average value (Ll) of the luminance component in order to reduce the dynamic range of the average value and encoding a luminance block (Le) obtained by adding (105, 302) together the luminance residual block (Lr) and the second representation (ƒ(Ll), ƒ(Ll)D) of the average value.

Abstract: A method and apparatus for determining an output value representing a picture data by applying a piece-wise linear function on an input value representing a picture data, said piece-wise linear function comprising at least one piece characterized by a slope value ai, an offset value and an interval defined over a range of values comprised between a lower bound and an upper bound.

Abstract: A method, device, computer program product and a processor readable medium is provided for signaling, in a bitstream representing a LDR picture obtained from an HDR picture. In one embodiment, both a picture/video format of a decoded version of the LDR picture, denoted an output LDR format, and a picture/video format of a decoded version of the HDR picture, denoted an output HDR format is provided. In one embodiment, the method includes encoding in the bitstream a second syntax element which is distinct from the first syntax element and which defines the output HDR format.

Abstract: The present principles relates to a method for intra-predictive encoding a coding unit comprising picture data, said intra-predictive encoding depending on a prediction tree and a transform tree, characterized in that the method further comprises: —obtaining said prediction tree by spatially partitioning the coding unit according to a non-square partition type; —determining said transform tree from said coding unit in order that each of its leaves is embedded into a unique unit of said obtained prediction tree; and —signaling in a signal the size of the leaves of said transform tree and said a non-square partition type.

Abstract: Method and apparatus for intra prediction in video encoding and decoding A method and an apparatus for video encoding and decoding, and more particularly, a method and an apparatus for performing intra prediction using reference sample portion having a thickness of at least two pixels and intra prediction modes based on such reference sample portion The intra-prediction mode may specify a direction and a propagation model for determining the manner of propagating samples in the prediction block. Using a reference sample portion having a thickness of at least two pixels allows the variations in the pixel values to be used in propagating the samples in the prediction block.

Abstract: A method for determining a luminance value used to process color samples in a decoder or encoder is provided comprising determining (33, 44) a luminance sample associated with a chroma sample position in a common space; and applying (34, 492) the determined luminance sample in a process that depends on luminance that is being applied to the chroma sample.

Abstract: The present disclosure generally relates to a method for signaling, in a bitstream representing a LDR picture and an illumination picture both obtained from an HDR picture, both a picture/video format of a decoded version of said LDR picture, called an output LDR format, and a picture/video format of a decoded version of said HDR picture, called an output HDR format, the method comprising encoding in the bitstream a first syntax element defining the output LDR format. The method is characterized in that it further comprises encoding in the bitstream a second syntax element which is distinct from the first syntax element and which defines the output HDR format. The disclosure further relates to an encoding/decoding method/device, a computer program product, a processor readable medium, a non-transitory storage medium and a signal.

Abstract: The present invention generally relates to a method and device for tone-mapping an image. The method is characterized in that it comprises: obtaining (12) a residual image by dividing the image by a backlight image determined (11) from the image, and obtaining (13) a tone-mapped image by tone-mapping to the residual image.

Abstract: The present invention generally relates to a method and device for encoding an image. The method comprises: —encoding (12) a backlight image determined (11) from the image; —obtaining (13) a residual image by dividing the image by a decoded version of the backlight image, —obtaining (16) a tone-mapped residual image by tone-mapping the residual image; and —encoding (19) the tone-mapped residual image. The invention relates also to a method and device for decoding a bitstream representing a residual image calculated by dividing an image by a backlight image.