Abstract: The present invention concerns a method for encoding an image, comprising the encoding of mode information representing a prediction mode for encoding a current block of pixels according to an Intra coding mode, the method comprising for the determination of set of most probable modes defining at least one candidate for a most probable mode to be the mode information of a neighbor-block if it exists; wherein a candidate for a most probable mode is the horizontal or vertical mode information if this neighbor-block exists and has been encoded using a predetermined coding mode.

Abstract: The invention relates to video coding. A method of encoding or decoding such a video sequence according to the invention comprises: obtaining a reconstructed frame area made of an array of sample values; applying a sample adaptive offset, SAO, filtering to the reconstructed frame area based on SAO parameters; wherein at least one of the SAO parameters is determined independently of the sample values of the reconstructed frame area. Preferably, the sample-independent SAO parameters define an Edge Offset filtering.

Abstract: The invention concerns a method and a device for processing images, e.g. for encoding or decoding the images into or from a bitstream, using a palette prediction mode as defined in HEVC SCC. The images are split into hierarchical coding structures.

Abstract: For an image portion to encode an initial set of motion information predictors is obtained. It is tested whether the number of motion information predictors in the initial set is lower than a target number and, if so, one or more motion information predictors are added to the initial set to generate a set of motion information predictors having controlled diversity. The motion information predictors of the initial set are actual motion information predictors, having motion vectors obtained from image portions of the image being encoded or of a reference image, and potential motion information predictors for addition include one or more further such actual motion information predictors and also include one or more virtual motion information predictors not having motion vectors obtained from image portions of said image being encoded or of a reference image. A motion information predictor for the image portion to encode is selected from the generated set of motion information predictors.

Abstract: For an image portion to encode an initial set of motion information predictors is obtained. It is tested whether the number of motion information predictors in the initial set is lower than a target number and, if so, one or more motion information predictors are added to the initial set to generate a set of motion information predictors having controlled diversity. The motion information predictors of the initial set are actual motion information predictors, having motion vectors obtained from image portions of the image being encoded or of a reference image, and potential motion information predictors for addition include one or more further such actual motion information predictors and also include one or more virtual motion information predictors not having motion vectors obtained from image portions of said image being encoded or of a reference image. A motion information predictor for the image portion to encode is selected from the generated set of motion information predictors.

Abstract: The invention relates to the encoding or decoding of at least one portion of an image by predicting the at least one portion using at least one predictor, the at least one predictor being determined as a function of at least one reference image portion and as a function of values of a plurality of items of motion information. After having obtained a value of a first item of the plurality of items, a value of a second item is evaluated as a function of the obtained value of the first item, the second item being an item of the plurality of items and being distinct from the first item. Next, the at least one predictor is determined as a function of the at least one reference image portion and as a function of the first and second items.

Abstract: For an image portion to encode an initial set of motion information predictors is obtained. It is tested whether the number of motion information predictors in the initial set is lower than a target number and, if so, one or more motion information predictors are added to the initial set to generate a set of motion information predictors having controlled diversity. The motion information predictors of the initial set are actual motion information predictors, having motion vectors obtained from image portions of the image being encoded or of a reference image, and potential motion information predictors for addition include one or more further such actual motion information predictors and also include one or more virtual motion information predictors not having motion vectors obtained from image portions of said image being encoded or of a reference image. A motion information predictor for the image portion to encode is selected from the generated set of motion information predictors.

Abstract: A decoding method wherein a motion vector is associated with a block of pixels of a current image, wherein the image is subdivided into spatial subdivisions, wherein the block of pixels belongs to a current spatial subdivision and is to be predicted using an Intra Block Copy mode, using a predictor block of pixels of the image designated by the motion vector, and wherein the predictor block designated by the motion vector may belong to any one of previously decoded spatial subdivisions in the current image. Embodiments provide enhancements to the Intra Block Copy Mode of the HEVC standard.

Abstract: An image portion to encode an initial set of motion information predictors is obtained. If the number of motion information predictors in the initial set is lower than a target number then, one or more motion information predictors are added to the initial set to generate a set of motion information predictors having controlled diversity. The motion information predictors of the initial set are actual motion information predictors, having motion vectors obtained from image portions of the image being encoded or of a reference image. Potential additional motion information predictors include one or more actual motion information predictors and also include one or more virtual motion information predictors not having motion vectors obtained from image portions of the image being encoded or of a reference image. A motion information predictor for the image portion to be encoded is selected from the generated set of motion information predictors.

Abstract: A method of performing sample adaptive offset (SAO) filtering on a sequence of images comprises associating a fixed set of four offset values with at least one direction of edge-type filtering. For every image area for which it is determined that edge-type filtering is to be used and for which it is determined that a direction of the edge-type filtering is said at least one direction, the fixed set of four offset values associated with said at least one direction is systematically used. Corresponding methods of generating SAO parameters and methods of encoding and decoding sequences of images are also provided.

Abstract: The value of a quantization parameter for at least one second color component of an image or image portion is determined using a current color format among several possible color formats. The determination comprises the steps of selecting at least one function associated with a possible color format, and determining the value of the quantization parameter for the second color component by applying said at least one function to a value of an intermediate quantization parameter which is based on the value of the quantization parameter of the first color component of the image or image portion. The at least one function is selected independently from the current color format.

Abstract: For an image portion to encode an initial set of motion information predictors is obtained. It is tested whether the number of motion information predictors in the initial set is lower than a target number and, if so, one or more motion information predictors are added to the initial set to generate a set of motion information predictors having controlled diversity. The motion information predictors of the initial set are actual motion information predictors, having motion vectors obtained from image portions of the image being encoded or of a reference image, and potential motion information predictors for addition include one or more further such actual motion information predictors and also include one or more virtual motion information predictors not having motion vectors obtained from image portions of said image being encoded or of a reference image. A motion information predictor for the image portion to encode is selected from the generated set of motion information predictors.

Abstract: The invention relates to the valence-based encoding of connectivity data of a 3D mesh. A command is generated for each free edge of each vertex traversed and describes the vertex at the other end of the edge. The obtained list of commands is encoded by mapping each command onto a symbol. A mapping table associating commands with a set of respective consecutive numeral symbols is used. The list of symbols is then encoded, separately to the encoding of parameters of the commands. A joint encoding may be used to encode two or more consecutive symbols using a single coding word. A look-up table may be used based on the valence values intrinsically defined by each symbol, in order to give priority to the most frequent valence values (usually around 6). Prior to generating the commands, a vertex may be added to the 3D mesh to artificially fill any hole therein.

Abstract: An encoding method comprises obtaining a target number of motion information predictors to be used for an image portion to encode and generating a set of motion information predictors using the obtained target number.

Abstract: The invention concerns a method, device, and computer program for motion vector prediction in scalable video encoder and decoder. It concerns the process to determine motion information predictor in the enhancement layer of a scalable encoding scheme also known as motion derivation process. It comprises a correction of the position in the reference layer used to pick-up the more relevant motion information available due to the compression scheme. Accordingly, motion information prediction is improved.

Abstract: The present invention concerns a method and a device for encoding or decoding blocks of pixels in the process of encoding or decoding a video. It concerns more particularly methods to handle parallelization when using INTRA Block Copy mode of HEVC Screen Content extension. It is based on the control of the area available for providing predictor blocks in INTRA Block Copy mode. Accordingly, the implementation is simple in order to allow parallelized process.

Abstract: The present invention is related to video coding and decoding, in particular HEVC RExt that define the adaptive residual color transform, Adaptive RCT, of a residue of pixels. Compared to HEVC RExt where Adaptive RCT is signalled at Coding Unit level, embodiments of the invention propose to signal it in the bitstream in association with two or more coding units forming the image. In other words, it is signalled at a level higher than the CU level, for instance at sequence or frame or slice or tile or coding tree block level. In addition, various flags at this higher level make it possible to generically define the applying or not of RCT for various respective coding modes, for instance Inter coding mode, Intra Block Copy coding mode or Intra coding mode where Chroma and Luma modes are the same. Such approach makes it possible to reduce the amount of evaluations to be performed.

Abstract: A method of encoding a sequence of images comprises performing area-by-area loop filtering on at least one image of the sequence and disabling such area-by-area loop filtering on at least one other image of the sequence. The images of the sequence are associated with respective levels from a plurality of levels, the levels corresponding to different respective rate-distortion balances or to different image qualities, and the images on which the area-by-area loop filtering is disabled are determined in dependence upon the levels.

Abstract: The value of a quantization parameter for at least one second color component of an image or image portion is determined using a current color format among several possible color formats. The determination comprises the steps of selecting at least one function associated with a possible color format, and determining the value of the quantization parameter for the second color component by applying said at least one function to a value of an intermediate quantization parameter which is based on the value of the quantization parameter of the first color component of the image or image portion. The at least one function is selected independently from the current color format.

Abstract: The invention relates to the encoding and decoding of texture mapping data of a textured 3D object. A 3D object is usually represented by connectivity, geometry and property data. The texture data, belonging to the property data, include a texture image; a texture coordinates table having entries, each entry defining coordinates in the texture image; and texture indexes associating each vertex of a polygon in the 3D object with an entry in the texture coordinates table. The present invention proposes to search for and delete entry duplicates from the texture coordinates table. To reduce encoding complexity, the search and deletion are based on the connectivity data. This is to exploit redundancies between the mesh connectivity for the polygons within the 3D object and the texture connectivity for the texture polygons within the texture image.