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: 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: In one example, a device includes a memory configured to store video data and a video decoder configured to decode an exponential Golomb codeword representative of at least a portion of a value for an escape pixel of a palette-mode coded block of video data, the video decoder is configured to decode the exponential Golomb codeword using exponential Golomb with parameter 3 decoding, and decode the block using the value for the escape pixel.

Abstract: Techniques and systems are provided for encoding video data. For example, restrictions on certain prediction modes can be applied for video coding. A restriction can be imposed that prevents inter-prediction bi-prediction from being performed on video data when certain conditions are met. For example, bi-prediction restriction can be based on whether intra-block copy prediction is enabled for one or more coding units or blocks of the video data, whether a value of a syntax element indicates that one or more motion vectors are in non-integer accuracy, whether both motion vectors of a bi-prediction block are in non-integer accuracy, whether the motion vectors of a bi-prediction block are not identical and/or are not from the same reference index, or any combination thereof. If one or more of these conditions are met, the restriction on bi-prediction can be applied, preventing bi-prediction from being performed on certain coding units or blocks.

Abstract: This disclosure describes techniques for coding transform coefficients associated with a block of residual video data in a video coding process. Aspects of this disclosure include the selection of a scan order for both significance map coding and level coding, as well as the selection of contexts for entropy coding consistent with the selected scan order. This disclosure proposes a harmonization of the scan order to code both the significance map of the transform coefficients as well as to code the levels of the transform coefficient. It is proposed that the scan order for the significance map should be in the inverse direction (i.e., from the higher frequencies to the lower frequencies). This disclosure also proposes that transform coefficients be scanned in sub-sets as opposed to fixed sub-blocks. In particular, transform coefficients are scanned in a sub-set consisting of a number of consecutive coefficients according to the scan order.

Abstract: In one example, an apparatus for encoding video data includes a video encoder configured to select an intra-prediction mode to use to encode a block of video data, determine whether the block includes a sub-block of a size for which multiple transforms are possible based on the size of the sub-block and the selected intra-prediction mode, when the block includes the sub-block of the size for which multiple transforms are possible based on the size of the sub-block and the selected intra-prediction mode, select one of the multiple possible transforms, transform the sub-block using the selected one of the multiple possible transforms, and provide an indication of the selected one of the multiple possible transforms for the size of the block.

Abstract: This disclosure describes techniques for coding significant coefficient information for a video block in a transform skip mode. The transform skip mode may provide a choice of a two-dimensional transform mode, a horizontal one-dimensional transform mode, a vertical one-dimensional transform mode, or a no transform mode. In other cases, the transform skip mode may provide a choice between a two-dimensional transform mode and a no transform mode. The techniques include selecting a transform skip mode for a video block, and coding significant coefficient information for the video block using a coding procedure defined based at least in part on the selected transform skip mode. Specifically, the techniques include using different coding procedures to code one or more of a position of a last non-zero coefficient and a significance map for the video block in the transform skip mode.

Abstract: In an example a method of processing video data includes determining a run value that indicates a run-length of a run of a palette index of a block of video data, wherein the palette index is associated with a color value in a palette of color values for coding the block of video data, the method also includes determining a context for context adaptive coding of data that represents the run value based on the palette index, and coding the data that represents run value from a bitstream using the determined context.

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: In palette-based coding, a video coder may form a so-called “palette” as a table of colors representing the video data of a given block. The video coder may code index values for one or more pixels values of a current block of video data, where the index values indicate entries in the palette that represent the pixel values of the current block. A method includes determining a palette for a block of video data, identifying escape pixel(s) not associated with any palette entries, identifying a single quantization parameter (QP) value for all escape pixels of the block for a given color channel using a QP value for non-palette based coding of transform coefficients, dequantizing each escape pixel using the identified QP value, and determining pixel values of the block using the dequantized escape pixels and index values for any pixel(s) associated with any palette entries.

Abstract: Provided are systems and methods for entropy encoding video data. Samples of a block of video data are 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 including refraining from encoding the samples associated with the at least one group.

Abstract: Techniques for encoding a binary prediction vector for predicting a palette for palette-based video coding is described. In one example, a method of decoding video comprises receiving an encoded binary prediction vector for a current block of video data, decoding the encoded binary prediction vector using a run-length decoding technique, generating a palette for the current block of video data based on the binary prediction vector, the binary prediction vector comprising entries indicating whether or not previously-used palette entries are reused for the palette for the current block of video data, and decoding the current block of video data using the palette.

Abstract: A device for decoding video data includes a memory configured to store the video data; and one or more processors configured to receive, in a picture parameter set (PPS), a first syntax element indicating that a palette predictor is to be generated using PPS-level palette predictor initializers; receive, in the PPS, a second syntax element indicating a number of the PPS-level palette predictor initializers included in the PPS is equal to zero; and decode a block of video data based on the first syntax element and the second syntax element.

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.

Abstract: This disclosure provides systems, methods and apparatus for sample adaptive offset (SAO) scaling. For example, the apparatus may include a processor configured to determine an offset value for an SAO filter applied to video data to improve reconstruction of signal amplitudes in the video data. The processor may be further configured to determine a first value indicative of a bit depth and a second value indicative of a scale factor for the video data, to provide a scaled offset value based on applying the scale factor to the offset value, and to scale at least one color component of the video data according to the scaled offset value. The processor may also be configured to identify an edge offset category for a scaled group of neighboring pixel values, and to adjust the SAO filter based on the identified edge offset category.

Abstract: An example method of decoding video data includes determining a palette for decoding a block, the palette including entries each having a respective palette index, determining a reference run of palette indices for first pixels of the block, and determining a current run of palette indices for second pixels of the block, based on the reference run. Determining the second plurality of palette indices includes locating a reference index of the reference run, the reference index being spaced at least one line from an initial index of the current run, determining a run length of the reference run, a final index of the reference run being separated from the initial index of the current run by at least one index, copying the palette indices of the reference run as the current run of palette indices, and decoding pixels of the copied current run using the palette.

Abstract: In general, techniques are described for performing an intra block copying process to code video data. A video decoding device that includes a memory and one or more processors may perform the techniques. The memory may be configured to store a current block of a picture. The processors may be configured to perform an intra block copying process to decode the current block using a prediction block that is from a same slice or a same tile as that in which the coded current block resides, the prediction block restricted to be within a search region that only includes the same slice or the same tile as that in which the coded current block resides.

Abstract: In an example a method of processing video data includes determining palette indices of a first row of a block of video data, wherein the palette indices correspond to a palette of one or more colors for coding the block of video data, and wherein the palette indices of the first row include one or more indices that are associated with a color value in the palette and a syntax element that is not associated with a color value in the palette. The method also includes coding a run of palette indices of a second row of the block of video data relative to the palette indices of the first row, wherein the run includes the one or more indices that are associated with a color value in the palette and the syntax element that is not associated with a color value in the palette.

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: The techniques of this disclosure may be generally related to signaling values of a quantization matrix. In some examples, coefficient values in the quantization matrix may be downsampled with different factors based on where the coefficient values are located in the quantization matrix.