Abstract: Methods and apparatus are provided for signaling intra prediction for large blocks for video encoders and decoders. The intra prediction is signaled by selecting a basic coding unit size and assigning a single spatial intra partition type for the basic coding unit size. The single spatial intra partition type is selectable from among a plurality of spatial intra partition types. The at least one large block has a large block size greater than a block size of the basic coding unit. The intra prediction is hierarchical layer intra prediction and is performed for the at least one large block by at least one of splitting from the large block size to the basic coding unit size and merging from the basic coding unit size to the large block size.

Abstract: A computer-implemented method includes accessing a video frame that includes a plurality of pixels. The method also includes generating a spatial mask that identifies pixels whose likelihood of causing banding within the video frame meets at least a minimum threshold likelihood. The method also includes computing a local distribution for a region of the video frame that includes at least those pixels that were identified by the spatial mask to detect bands in the video frame. The method further includes determining that the detected bands in the video frame are at least a minimum threshold size. The method also includes applying dithering to those detected bands in the video frame that were determined to meet the minimum threshold size. Various other methods, systems, and computer-readable media are also disclosed.

Abstract: Methods and apparatus are provided for signaling intra prediction for large blocks for video encoders and decoders. An apparatus includes a video encoder (400) for encoding picture data for at least one large block in a picture by signaling intra prediction for the at least one large block. The intra prediction is signaled by selecting a basic coding until size and assigning a single spatial intra partition type for the basic coding until size. The single spatial intra partition type is selectable from among a plurality of spatial intra partition types. The at least one large block has a large block size greater than a block size of the basic coding unit. The intra prediction is hierarchical layer intra prediction and is performed for the at least one large block by at least one of splitting from the large block size to the basic coding until size and merging from the basic coding unit size to the large block size.

Abstract: In an example, a method of processing video data may include inferring a pixel scan order for a first palette mode encoded block of video data without receiving a block-level syntax element having a value representative of the pixel scan order for the first palette mode encoded block. The method may include decoding the first palette mode encoded block of video data using the inferred pixel scan order. The method may include receiving a block-level syntax element having a value representative of a pixel scan order for a second palette mode encoded block of video data. The method may include determining the pixel scan order for the second palette mode encoded block of video data based on the received block-level syntax element. The method may include decoding the second palette mode encoded block of video data using the determined pixel scan order.

Abstract: A banding detection application generates a first set of pixel confidence values based on a first intensity difference value and first image scale associated with a first image, wherein each pixel confidence value included in the first set of pixel confidence values indicates a likelihood that a corresponding pixel included in the first image at the first image scale corresponds to banding in the first image. The banding detection application then generates a banding index corresponding to the first image based on the first set of pixel confidence values.

Abstract: In an example, a method of decoding video data includes generating a residual block of a picture based on a predicted residual block including reconstructing one or more residual values of the residual block based on one or more predicted residual values of the residual block. The method also includes generating a current block of the picture based on a combination of the residual block and a prediction block of the picture.

Abstract: This disclosure describes devices and methods 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 various embodiments, a banding detection application generates a first set of pixel confidence values based on a first intensity difference value and first image scale associated with a first image, wherein each pixel confidence value included in the first set of pixel confidence values indicates a likelihood that a corresponding pixel included in the first image at the first image scale corresponds to banding in the first image. The banding detection application then generates a banding index corresponding to the first image based on the first set of pixel confidence values.

Abstract: Methods incorporating extensions to copy-above mode for palette mode coding are disclosed. In one aspect, the method includes coding a current pixel of a current block of video data in copy-previous mode via coding a previous line index. The coding of the current pixel in copy-previous mode further including identifying a number of candidate values for the previous line index, identifying a number of escape pixels in a column of pixels above the current pixel in the current block, and reducing a number of candidate values of the previous line index by the number of identified escape pixels.

Abstract: In one example, an apparatus is disclosed for coding coefficients associated with a block of video data during a video coding process, the apparatus comprising a video coder configured to code information that identifies a scanning order associated with the block, wherein to code the information that identifies the scanning order associated with the block, the video coder is configured to determine a most probable scanning order for the block, and code an indication of whether the scanning order associated with the block is the most probable scanning order. In another example, to code the information that identifies the scanning order associated with the block, the video coder is further configured to, in the event the scanning order associated with the block is not the most probable scanning order, code an indication of the scanning order associated with the block.

Abstract: In an example a method of processing video data includes determining a first palette for a first block of video data that is located in a first row of blocks, generating a predictor palette for constructing at least one second palette of at least one second block of video data in the first row of blocks coded, reinitializing the predictor palette for determining a third palette of a third block of video data that is located in a second row of blocks, wherein re-initializing the predictor palette comprises re-initializing the predictor palette based on the one or more palette entries of the first palette or an initial predictor palette generated after coding the first block, determining the third palette of the third block based on the re-initialized predictor palette, and coding the third block using the third palette.

Abstract: Techniques are described for harmonizing coding techniques when residual differential pulse code modulation (RDPCM) is applied to a residual block. In some examples, a scan order used for such a residual block may be required to be the same as when the residual block is generated from intra-predicting the current block and when the residual block is generated from inter-predicting or intra block copy predicting the current block.

Abstract: In an example, a method of coding video data includes determining a first palette having first entries indicating first pixel values, determining, based on the first entries of the first palette, one or more second entries indicating second pixel values of a second palette, and coding pixels of a block of video data using the second palette.

Abstract: A device for decoding video data receives the video data, determines a scaling parameter for a block of the video data; and scales the block in a video decoding loop using the scaling parameter to increase a dynamic range for luminance values of the block. A device for encoding video data partitions the video data into blocks; determines a scaling parameter for a block of the video data; and scales the block in a video encoding loop using the scaling parameter to decrease a dynamic range for luminance values of the block.

Abstract: The method includes receiving video blocks that are each associated with a table having entries specifying pixel values used in the blocks. The method further includes dividing the blocks into sub-blocks each having an array of pixels. The method also includes selecting a sub-block scanning order that specifies an order in which the plurality of sub-blocks are to be encoded and a pixel scanning order that specifies an order in which the pixels of each sub-block are to be encoded. The scanning order and the pixel scanning order are selected based at least in part upon pixel value distributions and a bit rate for encoding the block according to the scanning or pixel scanning order, respectively. The blocks are then encoded using the selected scanning order and pixel scanning order and the index values in the table.

Abstract: Methods and apparatus are provided for signaling intra prediction for large blocks for video encoders and decoders. The intra prediction is signaled by selecting a basic coding unit size and assigning a single spatial intra partition type for the basic coding unit size. The single spatial intra partition type is selectable from among a plurality of spatial intra partition types. The at least one large block has a large block size greater than a block size of the basic coding unit. The intra prediction is hierarchical layer intra prediction and is performed for the at least one large block by at least one of splitting from the large block size to the basic coding unit size and merging from the basic coding unit size to the large block size.

Abstract: Systems, methods, and computer readable media are described for generating a regional nesting message. In some examples, a video bitstream is obtained and an encoded video bitstream is generated using the video data. The encoded video bitstream includes a regional nesting message that contains a plurality of nested messages and a plurality of region data defining a plurality of regions of a picture of the encoded video bitstream. For example, a first nested message of the regional nesting message includes a first set of data and a first region identifier indicating that the first set of data is to be applied to a first region of the plurality of regions of the picture.

Abstract: Processing high dynamic range and or wide color gamut video data using a fixed-point implementation. A method of processing video data may include receiving one or more supplemental enhancement information (SEI) messages that contain information specifying how to determine parameters for performing an inverse dynamic range adjustment process, receiving decoded video data, and performing the inverse dynamic range adjustment process on the decoded video data using fixed-point computing in accordance with the information in the one or more SEI messages.

Abstract: Systems, methods, and computer readable media are described for processing content color volume messages. In some examples, video data is obtained. The video data can include video data obtained from a camera, encoded video data, or decoded video data. Content color volume information associated with the video data is processed. The content color volume information is indicative of the content color volume of one or more pictures of the video data. For example, the content color volume information includes a first luminance value associated with a minimum luminance of the one or more pictures, a second luminance value associated with a maximum luminance of the one or more pictures, and one or more chromaticity coordinates of one or more color primaries describing a color gamut of the one or more pictures.

Abstract: This disclosure describes devices and methods 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.