Abstract: Systems, methods, and computer-readable storage media for signaling filters for reference picture resampling are described. One example involves obtaining an encoded video bitstream associated with the video data, identifying a current picture and at least one reference picture from the encoded video bitstream, and identifying signaling data from the encoded video bitstream for the video data, the signaling data including a partial set of coefficient data for at least one filter. A complete set of coefficients (e.g., filter coefficients) is derived for the at least one filter from the partial set of coefficient data and characteristics of the at least one filter, and the current picture is processed using the complete set of coefficients for the at least one filter.

Abstract: A video decoder can be configured to determine a threshold number of regular coded bins for a first decoding pass; for a first set of coefficients, context decode syntax elements of a coefficient group until the threshold number of regular coded bins is reached; and in response to reaching the threshold number of regular coded bins, for a second set of coefficients, bypass decode additional syntax elements, wherein to bypass decode the additional syntax elements the video decoder, for a coefficient of the second set of coefficients, derives a value for a Rice parameter based on a sum of absolute values of neighboring coefficients to the coefficient; determine values for the first set of coefficients of the transform unit based on the context decoded syntax elements; and determine values for the second set of coefficients of the transform unit based on the additional syntax elements.

Abstract: An example device includes memory configured to store video data and one or more processors implemented in circuitry and communicatively coupled to the memory. The one or more processors are configured to determine whether a picture of the video data is an intra random access picture (IRAP) and determine whether all layers of the picture are independent. Based on the picture being an IRAP and all layers of the picture being independent, the one or more processors are configured to determine a value of a first syntax element to be indicative of an inter slice not being allowed in the picture and code the picture without using inter slice prediction.

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: A video decoder is configured to remove pictures from a decoded picture buffer based on the value of an explicitly coded syntax element. A video decoder may be configured to decode a syntax element indicating a picture to remove from a decoded picture buffer, and remove the first picture from the DPB. The video decoder may then decode a current picture, and store the decoded current picture in the DPB.

Abstract: A device is configured to modify, based on chroma phase shifts in a horizontal direction, a horizontal component of a chroma location pointed to by a motion vector of a current block of a current picture. The chroma location is in a reference picture that has a different resolution or a different chroma sampling type from the current picture. The device may modify, based on chroma phase shifts in a vertical direction, a vertical component of the chroma location. Additionally, the device may generate, based on chroma samples of the reference picture corresponding to a modified chroma location chroma samples of a prediction block for a current block of the current picture. The modified chroma location is defined by the modified horizontal and vertical components of the chroma location. The device may code the current block based on the prediction block for the current block.

Abstract: A device for decoding video data determines a quantization parameter (QP) for a block of transform coefficients, wherein the block of transform coefficients is a non-square, rectangular block; determines a value for (log2 (width)+log2 (height), wherein width represents a width of the block of transform coefficients and height represents a height of the block of transform coefficients; in response to the value not being divisible by 2, determines a modified QP for the block of transform coefficients based on the QP; inverse transforms the transform coefficients to determine a block of quantized residual samples; and dequantizes the quantized residual samples based on the modified QP to determine a block of residual samples.

Abstract: Examples for performing adaptive loop filtering in video coding are described. A video decoder may determine that a number of parameter sets, which each include one or more adaptive filters for adaptive loop filtering, that a current coding structure of the video data refers to for adaptive loop filtering is equal to zero. Based on the number of the parameter sets that the current coding structure refers to for adaptive loop filtering being equal to zero, the video decoder may determine which fixed filter from a set of fixed filters to use for adaptive loop filtering without receiving a syntax element that indicates whether one of the set of fixed filters is to be used for adaptive loop filtering. The video decoder may perform adaptive loop filtering on the current block based on the fixed filter from the set of fixed filters.

Abstract: Systems and techniques are described herein for processing video data using a neural network system. For instance, a process can include generating, by a first convolutional layer of an encoder sub-network of the neural network system, output values associated with a luminance channel of a frame. The process can include generating, by a second convolutional layer of the encoder sub-network, output values associated with at least one chrominance channel of the frame. The process can include generating a combined representation of the frame by combining the output values associated with the luminance channel of the frame and the output values associated with the at least one chrominance channel of the frame. The process can include generating encoded video data based on the combined representation of the frame.

Abstract: Aspects of the present disclosure provide techniques for using a radio access network (RAN) level negative acknowledgement (NAK) feedback to indicate at least one missing frame from an encoding device. The RAN level NAK feedback replaces or preempts a decoding device sending an end-to-end feedback to the encoding device using real-time transport protocol (RTP) that has a long latency and may cause freezes at the decoding device. For example, an encoding device may send to a network entity a request for a configuration that configures the encoding device to transmit media frames to the decoding device. The network entity may provide a NAK feedback indicating at least one missing frame. Having received the configuration in response to the request, the encoding device transmits media frames to the decoding device via the network entity, and monitors for NAK feedback from the network entity in accordance with the configuration.

Abstract: A device for coding video data is configured to code a motion vector difference (MVD) value using a codeword prefix and a codeword suffix. Based on an absolute value, minus 2, of the MVD value being 131070 or greater, the codeword prefix of the MVD value is equal to 1111 1111 1111 1111 and the codeword suffix is coded using the fixed length code.

Abstract: An example device for coding video data determines a first reference block in a first reference picture for a first block of a current picture. Based on the first reference picture being a different size than the current picture, the device codes the first block with a first inter-coding tool of a first set of inter-coding tools, wherein a first particular tool of a plurality of inter-coding tools is disabled. The device determines a second reference block in a second reference picture for a second block of the current picture. Based on the second reference picture being the same size as the current picture, the device codes the second block with a second inter-coding tool of a second set of inter-coding tools, wherein the first particular tool is enabled.

Abstract: An example device includes memory configured to store video data and one or more processors implemented in circuitry and coupled to the memory. The one or more processors are configured to determine whether transform skip mode is used for a current block of the video data. The one or more processors are configured to disable level mapping for residual coding based on transform skip mode being used for the current block. The one or more processors are configured to code the current block without applying level mapping.

Abstract: A method of decoding video data includes receiving a value indicating that a lossless mode is enabled for a block of the video data and, in response to determining that the value indicates that the lossless mode is enabled for the block of the video data, determining a maximum size for a lossless-coded transform block of the block of the video data is set to a maximum scanning size of the non-lossless coding block. The method further includes inverse scanning residual values for the block of the video data based on the maximum size for the lossless-coded transform block to generate a residual block for the block of the video data and reconstructing the block of the video data based on the residual block.

Abstract: A video encoder derives a minimum allowed base quantization parameter for video data based on an input bitdepth of the video data, determines a base quantization parameter for a block of the video data based on the minimum allowed base quantization parameter, and quantizes the block of video data based on the base quantization parameter. In a reciprocal fashion, a video decoder derives a minimum allowed base quantization parameter for the video data based on an input bitdepth of the video data, determines a base quantization parameter for a block of the video data based on the minimum allowed base quantization parameter, and inverse quantizes the block of video data based on the base quantization parameter.

Abstract: An example method includes, receiving an encoded picture of 360-degree video data, the encoded picture of 360-degree video data being arranged in packed faces obtained from a projection of a sphere of the 360-degree video data; decoding the picture of encoded 360-degree video data to obtain a reconstructed picture of 360-degree video data, the reconstructed picture of 360-degree video data being arranged in the packed faces; padding the reconstructed picture of 360-degree video data to generate a padded reconstructed picture of 360-degree video data; in-loop filtering the padded reconstructed picture of 360-degree video data to generate a padded and filtered reconstructed picture of 360-degree video data; and storing the padded and filtered reconstructed picture of 360-degree video data in a reference picture memory for use in predicting subsequent pictures of 360-degree video data.

Abstract: A device for decoding video data performs coefficient coding for a residual block of video data encoded using a transform skip mode by determining values for a first neighboring coefficient and a second neighboring coefficient and determining a context offset for the coefficient currently being decoded based on the value for the first neighboring coefficient and the value for the second neighboring coefficient. Performing coefficient coding includes, for example, performing sign coding, level mapping, and context derivation. The device performs coefficient coding to determine the residual block and adds the residual block to a predicted block to determine a reconstructed block.

Abstract: An example method includes decoding, from a coded video bitstream, a first syntax element that specifies a constraint for a second syntax element that specifies whether subpicture information is present in the coded video bitstream and whether more than one subpicture is allowed to be present in the coded video bitstream; and decoding, based on the constraint specified by the first syntax element, the second syntax element.

Abstract: Systems, methods, and computer-readable storage media are provided for decoded picture buffer (DPB) operations and rewriting access unit delimiters (AUDs) after bitstream extractions. An example method can include storing one or more pictures associated with an access unit (AU) in a decoded picture buffer (DPB), the AU including a first plurality of pictures, the first plurality of pictures corresponding to a plurality of video coding layers; after each picture of a second plurality of pictures associated with the AU is removed from a coded picture buffer (CPB), removing at least one picture of the one or more pictures from the DPB; and storing, in the DPB, each picture of the second plurality of pictures removed from the CPB.

Abstract: Techniques are described for improving video coding. For example, a first block of a picture included in an encoded video bitstream can be obtained. A second block of the picture can be determined as being coded (e.g., encoded) using a type of block-based quantized residual domain pulse code modulation (BDPCM) mode, such as vertical BDPCM mode or horizontal BDPCM mode. In the event the second block is coded using the vertical BDPCM mode, a vertical intra-prediction mode can be determined for an intra-prediction mode list for the first block. The vertical intra-prediction mode can be added to the intra-prediction mode list for the first block. In the event the second block is coded using the horizontal BDPCM mode, a horizontal intra-prediction mode can be determined for the intra-prediction mode list for the first block and the horizontal intra-prediction mode can be added to the intra-prediction mode list.