Abstract: A method and apparatus for detecting a complex region of an image are disclosed. In one example, the method may involve calculating complexity values for a current block, a next block, and a previous block. The method may involve: (i) detecting that the previous complexity value is less than a first threshold value, and that the next complexity value is greater than a second threshold value; and (ii) determining that neither a transition to the current block nor a transition to the previous block is a flat-to-complex region transition. The method may involve detecting a flat-to-complex region transition when transitioning to the next block in response to (i) and (ii).

Abstract: A system and method for flatness detection for display stream compression (DSC) is disclosed. In one aspect, the method includes determining a first complexity value for a previous block of video data, a second complexity value for a current block of the video data, and a third complexity value for a next block of the video data. The method also includes determining whether the current block includes a transition from a complex region to a flat region based at least in part on the first, second, and third complexity values.

Abstract: Entropy coding techniques for display stream compression (DSC) are disclosed. In one aspect, a method of entropy coding video data includes partitioning a block of the video data into a plurality of groups of samples based at least in part on a coding mode of the block. The method further includes entropy coding the block via performing a group-wise skip on at least one of the groups in response to all of the samples in the at least one group being equal to a predetermined value.

Abstract: According to certain aspects, an apparatus for coding video data includes a memory for storing the video data and a processor. The memory includes a buffer. The processor is configured to receive the video data to be coded. The processor is further configured to determine a Lagrangian parameter for a coding mode based at least in part on a bit rate of the coding mode and a fullness of the buffer.

Abstract: An apparatus for coding video data according to certain aspects includes a memory for storing the video data and a processor. The memory includes a buffer. The processor is configured to receive the video data to be coded. The processor is further configured to determine a quantization parameter (QP) of a current block of the video data without considering a type of content of the video data and a rate-distortion model associated with the type of content. The processor is also configured to code the current block in a bitstream using the determined QP.

Abstract: An apparatus configured to encode video data comprising a memory configured to store a block of video data and one or more processors in communication with the memory. The one or more processors are configured to determine a coding mode for encoding the block of video data from among one or more coding modes, wherein the coding mode is determined based on a maximum syntax element size, encode the block of video data in a plurality of substreams according to the determined coding mode to create a plurality of encoded substreams of video data, store the plurality of encoded substreams of video data in respective balance first-in, first-out (FIFO) buffers, and multiplex the plurality of encoded substreams in a bitstream for transmitting to a video decoder.

Abstract: A system and method for coding video data in pattern mode for display stream compression (DSC) is disclosed. In one aspect, the method includes determining that a first pattern in a current block of video data is not in a pattern database comprising a plurality of patterns, and adding the first pattern to the pattern database. The first pattern may be associated with a first index identifying a location of the first pattern in the pattern database. The method further includes coding the current block in pattern mode at least in part via signaling (i) the first pattern determined not to be in the pattern database and (ii) the first index identifying the location of the first pattern in the first database.

Abstract: Methods and apparatus for coding video information having a plurality of video samples are disclosed. Blocks for video data are coded by an encoder based upon a quantization parameter (QP) for each block. The video data may be coded in a particular color space, such as YCoCg, wherein different QP values may be used for coding different color components of the video data. Because the human eye is generally more sensitive to differences in luma compared to chroma, and more sensitive to differences in chromatic green than chromatic orange, when the YCoCg color space is used to code the video data, different QP values may be determined for each color component channel. By coding each color component using different QP values, loss from quantization may be reduced while also reducing the appearance of visual artifacts in the coded video data.

Abstract: Methods and apparatus for coding video information having a plurality of video samples are disclosed. Blocks for video data are coded by an encoder based upon a quantization parameter (QP) for each block. The QP used for each block may be limited by a maximum QP value. A buffer fullness of a buffer unit may be determined that indicates of a ratio between a number of bits currently occupied in the buffer unit and a current capacity of the buffer unit. The encoder may determine an adjustment value for the maximum QP based upon the determined buffer fullness. By dynamically adjusting the maximum QP for coding blocks of video data, distortion from quantization may be reduced while preventing the buffer unit from overflowing or emptying.

Abstract: Methods and apparatus for coding video information having a plurality of video samples are disclosed. Video samples are partitioned into groups for transmission within a single clock cycle, wherein the samples are associated with a bit length B, and a group having a group size K. The sample group is mapped to a code number and coded to form a vector-based code comprising a first portion identifying a type of look-up-table used to performing the mapping, and a second portion representing the samples of the group. The look-up-table may be constructed based upon occurrence probabilities of different sample groups. In addition, different types of look-up-tables may be used for different B and K values.

Abstract: Systems and methods are disclosed for calculating a distortion value of a frame or block, in a number of color spaces, and determining an optimal coding mode based on the calculated distortion values. One embodiment includes a system having a video source that includes a video camera or a video archive that contains previously stored video content, and a processor configured to encode the stored video content.

Abstract: A method for coding a block of video data in simplified block prediction mode of a constant bitrate video coding scheme for transmission over display links is disclosed. In one aspect, the method includes determining a candidate block to be used to predict a current block in a current slice, the candidate block being within a range of pixel positions that each correspond to a reconstructed pixel in the current slice. The range of pixel positions may comprise (i) a first region including one or more first pixel positions in a first line of pixels that overlaps the current block, and (ii) a second region including one or more second pixel positions in a second line of pixels that does not overlap the current block. The method may further comprise determining and signaling a prediction vector indicative of a pixel position of the candidate block.

Abstract: Provided are systems and methods for used fixed-point instead of floating point techniques in order to calculate various parameters for coding video data, including target rate, QP adjustment, buffer fullness, a Lagrangian parameters for a bitrate, and/or a Lagrangian parameter for the fullness of the buffer. By determining one or more of the parameters using fixed-point, hardware implementation costs may be decreased.

Abstract: Provided are systems and methods for adjusting quantization parameters of blocks of video data to be encoded, in order to reduce visual artifacts between slices of video data. Each slice includes one or more blocks organized in one or more lines, and can be coded independently without information from any other slices of video data. A complexity value of a current block corresponding to a last block of the slice on a particular line is determined and used to determine whether the current block includes a transition from a complex region to a flat region, wherein complex regions are characterized as having higher complexity in comparison to flat regions. In response to a determination that the current block includes such a transition, the QP for coding the current block may be decreased.

Abstract: Provided are systems and methods for entropy encoding video data. A plurality of samples of a block of video data is partitioned into one or more groups of samples, based upon a coding mode of the block and a chroma subsampling image format of the samples. Entropy coding is performed on the block via performing a group-wise skip on at least one of the one or more groups in response to all of the samples in the at least one group having a value equal to a predetermined value, the group-wise skip comprising refraining from encoding the samples associated with the at least one group.

Abstract: A method for coding a block of video data in block prediction mode of a constant bitrate video coding scheme for transmission over display links is disclosed. In one aspect, the method includes determining one or more first candidate regions to be used to predict a current region within the block of video data using a first partitioning scheme, determining one or more second candidate regions to be used to predict the current region using a second partitioning scheme, determining that a first cost associated with coding the current region using the first partitioning scheme is greater than a second cost associated with coding the current region using the second partitioning scheme, and coding the current region using the second partitioning scheme.

Abstract: Methods and apparatuses for modification to block size for transform mode in display stream compression are disclosed. In one aspect, the method involves selecting a current block and a next block of video data, calculating a first rate-distortion (RD) cost for coding the current and next blocks with a larger block size transform (LBT) mode, and calculating a second RD cost for coding each of the current and next blocks with another coding mode different from the LBT mode. The method may further involve determining whether the first RD cost is less than a sum of the second RD costs for the current and next blocks and coding the current and next blocks with the LBT mode in response to the first RD cost being less than the sum of the second RD costs for the current and next blocks.

Abstract: Methods and apparatuses for display stream compression pixel format extension using subpixel packing are disclosed. In one aspect, the method involves packing pixel values arranged in an O-channel format for encoding by an M-channel codec. The method may further involve receiving a set of input pixel values, each input pixel value including O input subpixel values arranged in the O-channel format. The method may involve rearranging each of the input subpixel values into a set of output pixel values, each set of output pixel values comprising M output subpixel values arranged in an M-channel format, O having a greater value than M, wherein at least a portion of the rearranged M output subpixels maintain their relative spatial positioning from prior to being rearranged from the O input subpixel values. The method may also involve providing the output pixel values to the M-channel codec.

Abstract: Techniques for quantization parameter (QP) for display stream compression (DSC) based on complexity measure are disclosed. In one aspect, a method for determining a QP value includes determining a complexity value of a plurality of previous blocks and selecting a technique from a plurality of defined techniques for calculating a QP adjustment value for a current block based on the determined complexity value. The method may further include calculating the QP adjustment value for the current block via the selected technique and determining the QP value for the current block based on the QP adjustment value.

Abstract: Quantization parameter (QP) update classification techniques for display stream compression (DSC) are disclosed. In one aspect, a method for determining a quantization parameter (QP) value includes determining whether a current block includes a transition from a flat region to a complex region or is a flat block and determining whether a previous block includes a transition from a flat region to a complex region or is a flat block. The method may also include selecting a default technique or an alternative technique for calculating a QP adjustment value for the current block based on whether the previous and current blocks include a transition from a flat region to a complex region or are flat blocks.