摘要:
In an example, aspects of this disclosure relate to a method of coding video data that generally includes determining prediction information for a block of video data, where the block is included in a coded unit of video data and positioned below a top row of above-neighboring blocks in the coded unit, and where the prediction information for the block is based on prediction information from one or more other blocks in the coded unit but not based on prediction information from any of the top row of blocks in the coded unit. The method also generally includes coding the block based on the determined prediction information.
摘要:
In general, techniques of this disclosure are related to determining a prediction characteristic associated with a coding unit of video data, wherein determining the prediction characteristic includes determining a prediction type that defines a number of prediction units associated with the coding unit. Techniques of this disclosure may also be related to generating a set of available intra-prediction modes for the coding unit based on the prediction characteristic, selecting an intra-prediction mode from the available intra-prediction modes, and applying one of the available intra-prediction modes to code the coding unit.
摘要:
This disclosure relates to techniques for reducing a cost of coding prediction information in video coding. Video blocks in a generalized P/B (GPB) frame are encoded using up to two motion vectors calculated from reference pictures in two separate reference picture lists that are identical. Video blocks of a GPB frame may, therefore, be encoded using a bidirectional prediction mode with a first motion vector from a reference picture in a first reference picture list and a second motion vector from the same or substantially similar reference picture in a second reference picture list. The techniques include jointly coding the first and second motion vectors for a video block of a GPB frame. The techniques include coding the first motion vector relative to a first motion predictor generated from a motion vector of a neighboring block, and coding the second motion vector relative to the first motion vector.
摘要:
In one example, a video decoder is configured to receive a value for a coding unit of video data, wherein the coding unit is partitioned into a plurality of sub-coding units, determine whether the sub-coding units are partitioned into further sub-coding units based on the value, and decode the sub-coding units and the further sub-coding units. In another example, a video encoder is configured to partition a coding unit of video data into a plurality of sub-coding units, determine whether to partition the sub-coding units into further sub-coding units, and encode the coding unit to include a value that indicates whether the sub-coding units are partitioned into the further sub-coding units.
摘要:
In an example, aspects of this disclosure relate to a method of coding video data that includes determining context information for a block of video data, where the block is included within a coded unit of video data, where the block is below a top row of blocks in the coded unit, and where the context information does not include information from an above-neighboring block in the coded unit. That method also includes entropy coding data of the block using the determined context information.
摘要:
A video block syntax element indicates whether all of the partitions of a video block are predicted based on a same reference list and no greater than quarter-pixel accuracy is used. If the video block syntax element is set, partition-level signaling of the reference lists is avoided. If the video block syntax element is not set, partition-level signaling of the reference lists occurs. If the video block syntax element is set, partition-level syntax elements may be used for each of the partitions of the video block, wherein the partition-level syntax elements each identify one of the reference lists and motion vector accuracy for a given one of the partitions.
摘要:
A video coder performs a padding operation that processes a set of border pixels according to an order. The order starts at a bottom-left border pixel and proceeds through the border pixels sequentially to a top-right border pixel. When the padding operation processes an unavailable border pixel, the padding operation predicts a value of the unavailable border pixel based on a value of a border pixel previously processed by the padding operation. The video coder may generate an intra-predicted video block based on the border pixels.
摘要:
In one example, this disclosure describes a method of codeword adaptation for variable length coding. The method comprises applying a first codeword adaptation scheme to a first group of codewords of a variable length coding (VLC) table to change a mapping of codewords to events in the VLC table; and applying a second codeword adaptation scheme to a second group of codewords of the VLC table to change the mapping of the codewords to the events in the VLC table.
摘要:
This disclosure describes techniques for coding transform coefficients for a block of video data. According to one aspect of this disclosure, a coder (e.g., an encoder or decoder) may map between a code number cn and a level_ID value and an run value based on a structured mapping. According to other aspects of this disclosure, the coder may map between a code number cn and a level_ID value and an run value for the current transform coefficient using a first technique or a second technique based on a coded block type of a block of video data being coded. For example, if the coded block type is a first coded block type, the coder may use a structured mapping. However, if the coded block type is a second coded block type different than the first coded block type, the coder may access one or more mapping tables stored in memory to perform the mapping.
摘要:
In one example, this disclosure describes method of coding video data. The method comprises coding a block of video data as one or more luminance blocks of transform coefficients and one or more chrominance blocks of transform coefficients, and coding a coded block pattern (CBP) for the block of video data. The CBP comprises syntax information that identifies whether non-zero data is included in each of the luminance blocks and each of the chrominance blocks. Coding the CBP includes selecting one or more variable length coding (VLC) tables based on a transform size used in performing one or more transforms on the one or more luminance blocks.