Embodiments of the present invention relate to methods and systems for ordering, communicating and applying pixel intra-prediction modes.

A method of encoding an image in a merge mode, the method including determining motion information of a current prediction unit, and generating a prediction block using the motion information; generating a residual block using an original block and the prediction block, transforming the residual block to generating a transformed block, quantizing the transformed block using a quantization parameter to generate a quantized block, and scanning the quantized block to entropy-code the quantized block; and encoding the motion information using effective spatial and temporal merge candidates of the current prediction unit. Further, a motion vector of the temporal merge candidate is a motion vector of a temporal merge candidate within a temporal merge candidate picture, and the quantization parameter is encoded using an average of two effective quantization parameters among a left quantization parameter, an upper quantization parameter and a previous quantization parameter of a current coding unit, also when the quantized block is larger than a predetermined size, the quantized block is divided into a plurality of subblocks to be scanned, and a scan pattern for scanning the plurality of subblocks is the same as a scan pattern for scanning quantized coefficients within each subblock. In addition, information indicating a position of a last non-zero quantized coefficient in a transform unit is transmitted to a video decoder.

A method of encoding an image in a merge mode, the method including determining motion information of a current prediction unit, and generating a prediction block using the motion information; generating a residual block using an original block and the prediction block, transforming the residual block to generating a transformed block, quantizing the transformed block using a quantization parameter to generate a quantized block, and scanning the quantized block to entropy-code the quantized block; and encoding the motion information using effective spatial and temporal merge candidates of the current prediction unit. In addition, a motion vector of the temporal merge candidate is a motion vector of a temporal merge candidate within a temporal merge candidate picture, and the quantization parameter is encoded using an average of two effective quantization parameters among a left quantization parameter, an upper quantization parameter and a previous quantization parameter of a current coding unit, also when the quantized block is larger than a predetermined size, the quantized block is divided into a plurality of subblocks to be scanned, and a scan pattern for scanning the plurality of subblocks is the same as a scan pattern for scanning quantized coefficients within each subblock. Further, a scanning scheme for scanning the quantized coefficients is determined according to an intra-prediction mode and a size of a transform unit.

A technique for determining an adaptive quantization parameter offset for a block of encoded video includes obtaining a rate control factor for the quantization parameter, determining a content-based quantization parameter factor for the quantization parameter, determining an adaptive variance based quantization offset based on content-based quantization parameter factors for a frame prior to the current frame, and combining the rate control factor, the content-based quantization parameter factor, and the adaptive offset to generate the quantization parameter.

Techniques are disclosed for the creation of multi-codec encoding profiles (or encoding ladders), which define quality and bitrate for each of the streams made available to clients for streaming a video. In particular, optimization techniques may take into account a quality rate function of each of the codecs when determining the encoding ladder. Additional considerations may include a network bandwidth distribution and/or a distribution of client types.

Systems and methods for hinting an encoder are disclosed in which a server monitors for information related to changes in frame rendering, calculates tolerance boundaries, rolling average frame time, and short-term trends in frame time, and uses those calculations to identify a frame time peak. The server then hints a codec (encoder) to modulate the quality settings of frame output in proportion to the size of the frame time peak. In certain embodiments, a renderer records one or more playthroughs in a game environment, sorts a plurality of frames from one or more playthroughs into a plurality of cells on a heatmap, and collects the list of sorted frames. A codec may then encode one or more frames from the list of sorted frames to calculate an average encoded frame size for each cell in the heatmap, and associate each average encoded frame size with a per-cell normalized encoder quality setting.

There are provided methods and apparatus for transform selection in video coding. An apparatus includes a video encoder (300) for encoding at least a block in a picture by selecting a transform (329) to apply to a residue of the block from a set of two or more available transforms (325, 326, 327). The transform is selected based on at least one of an inter prediction mode used to predict at least one reference for the block, one or more values corresponding to a motion vector, a value of a residue of one or more previously encoded blocks, a value of prediction data for the block, one or more transform selections of one or more neighboring reconstructed blocks, and a quantization step applied to transform coefficients for the residue of the block.

The coding efficiency of scalable video coding is increased by substituting missing spatial intra prediction parameter candidates in a spatial neighborhood of a current block of the enhancement layer by use of intra prediction parameters of a co-located block of the base layer signal. By this measure, the coding efficiency for coding the spatial intra prediction parameters is increased due to the improved prediction quality of the set of intra prediction parameters of the enhancement layer, or, more precisely stated, the increased likelihood, that appropriate predictors for the intra prediction parameters for an intra predicted block of the enhancement layer are available thereby increasing the likelihood that the signaling of the intra prediction parameter of the respective enhancement layer block may be performed, on average, with less bits.

Aspects of the disclosure provide a method and an apparatus including processing circuitry for video decoding. The processing circuitry decodes, from a coded video bitstream, coding information for a current picture. The coding information indicates that a geometric merge mode is enabled for a coding level higher than a picture level of the current picture and a maximum number of merge candidates satisfies a condition. The processing circuitry determines, based on a picture level parameter signaled for the current picture in the coded video bitstream, a maximum number of geometric merge mode merge candidates based on the picture level parameter and the maximum number of merge candidates. The maximum number of geometric merge mode merge candidates can be (i) 0 or (ii) one of 2 to the maximum number of merge candidates. The picture level parameter indicates the maximum number of geometric merge mode merge candidates.

Scalable video coding is rendered more efficient by deriving/selecting a subblock subdivision to be used for enhancement layer prediction, among a set of possible subblock subdivisions of an enhancement layer block by evaluating the spatial variation of the base layer coding parameters over the base layer signal. By this measure, less of the signalization overhead has to be spent on signaling this subblock subdivision within the enhancement layer data stream, if any. The subblock subdivision thus selected may be used in predictively coding/decoding the enhancement layer signal.