Abstract: Video coders and decoders perform transform coding and decoding on blocks of video content according to an adaptively selected transform type. The transform types are organized into a hierarchy of transform sets where each transform set includes a respective number of transforms and each higher-level transform set includes the transforms of each lower-level transform set within the hierarchy. The video coders and video decoders may exchange signaling that establishes a transform set context from which a transform set that was selected for coding given block(s) may be identified. The video coders and video decoders may exchange signaling that establishes a transform decoding context from which a transform that was selected from the identified transform set to be used for decoding the transform unit. The block(s) may be coded and decoded by the selected transform.

Abstract: Techniques are disclosed for coding video in applications where regions of video are inactive on a frame to frame basis. According to the techniques, coding processes update and reconstruct only a subset of pixel blocks of pixels within a frame, while other pixel blocks are retained from a previously coded frame stored in a coder's or decoder's reference frame buffer. The technique is called Backward Reference Updating (or “BRU”) for convenience. At a desired pixel block granularity, based on the activity between a current frame to be coded and its reference frame(s), BRU will only perform prediction, transform, quantization, and reconstruction on selected regions that are determined to be active. The reconstructed pixels in these active regions are directly placed onto a specified reference frame in memory instead of creating a new frame. Therefore, fewer memory transfers need to be performed.

Abstract: Systems and methods are configured for accessing data representing video content, the data comprising a set of one or more symbols each associated with a syntax element; performing a probability estimation, for encoding the data, comprising: for each symbol, obtaining, based on the syntax element for that symbol, an adaptivity rate parameter value, the adaptivity rate parameter value being a function of a number of symbols in the set of one or more symbols; updating the adaptivity rate parameter value as a function of an adjustment parameter value; and generating, based on the updated adaptivity rate parameter value, a probability value; generating a probability estimation; and encoding, based on the CDF of the probability estimation, the data comprising the set of one or more symbols for transmission.

Abstract: Disclosed is a method that includes receiving an image frame having a plurality of coded blocks, determining a prediction unit (PU) from the plurality of coded blocks, determining one or more motion compensation units arranged in an array within the PU, and applying a filter to one or more boundaries of the one or more motion compensation units. Also disclosed is a method that includes receiving a reference frame that includes a reference block, determining a timing for deblocking a current block, performing motion compensation on the reference frame to obtain a predicted frame that includes a predicted block, performing reconstruction on the predicted frame to obtain a reconstructed frame that includes a reconstructed PU, and applying, at the timing for deblocking the current block, a deblocking filter based on one or more parameters to the reference block, the predicted block, or the reconstructed PU.

Abstract: Video coding methods, apparatuses, and non-transitory computer readable mediums are provided. The method includes: obtaining a list of reference pictures comprising a plurality of pictures stored in a buffer, where the plurality of pictures comprise at least a first picture with a first spatial resolution, and a second picture with a second spatial resolution different from the first spatial resolution; obtaining a reference picture from the list of reference pictures; predicting a current picture by using the reference picture with its original spatial resolution without ensuring the reference picture to have a same spatial resolution as the current picture; and generating a bitstream based on a predicted current picture.

Abstract: Methods and apparatus are provided for encoding and decoding binary sets using adaptive tree selection. In one exemplary encoding method embodiment, picture data is encoded for a block in a picture; in which one of a plurality of trees structures is selected to code a binary set of data for indicating coefficient significance for the block. In another exemplary encoding method embodiment, picture data is encoded for a block in a picture, in which one or more trees are used to encode a binary set of data for indicating significance for the block, the one or more trees each having a plurality of nodes, at least one of the nodes of the one or more trees being modified responsive to at least one parameter.

Abstract: Methods and apparatus are provided for improved chroma encoding and decoding. An apparatus includes an encoder (400) for encoding picture data for at least a block in a picture. Multiple partition types are supported for intra chroma coding of the block. The multiple partition types include a set of chroma partition types and a set of luma partition types. The set of chroma partition types are different than the set of luma partition types.

Abstract: Methods and apparatus are provided for signaling intra prediction for large blocks for video encoders and decoders. An apparatus includes a video encoder 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 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 basic coding unit size. The intra prediction may be 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.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for reducing a quantity of buffers for a video codec. One of the methods includes determining, from a plurality of prediction modes, a prediction mode for data that represents frame data in a frame; in response to determining the prediction mode, selecting, using the prediction mode, one or more buffers from a plurality of buffers, each buffer of which is for a prediction mode from the plurality of prediction modes, a first quantity of buffers in the plurality of buffers being less than a second quantity of prediction modes in the plurality of prediction modes; retrieving, from each of the one or more buffers, historical data for the frame data; and in response to retrieving the historical data, generating, using the historical data, updated data for the frame data in the frame of the video sequence.

Abstract: Methods and apparatus are provided for improved chroma encoding and decoding. An apparatus includes an encoder for encoding picture data for at least a block in a picture. Multiple partition types are supported for intra chroma coding of the block. The multiple partition types include a set of chroma partition types and a set of luma partition types. The set of chroma partition types are different than the set of luma partition types.

Abstract: Video coding methods and apparatuses are provided. A set of two or more pictures is coded. The set includes at least a first picture coded with a first spatial resolution, and a second picture coded with a second spatial resolution different from the first spatial resolution. The set of two or more pictures is stored in a decoded picture buffer based on corresponding spatial resolutions. The set of two or more pictures stored in the decoded picture buffer is used as a set of reference pictures for coding one or more successive pictures subsequent to the set of two or more pictures. The set of two or more pictures is incorporated into a reference picture list that contains pictures with at least two different spatial resolutions.

Abstract: Methods and apparatus are provided for signaling intra prediction for large blocks for video encoders and decoders. An apparatus includes a video encoder 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 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 splitting from the large block size to the basic coding unit size.

Abstract: Methods and apparatus are provided for improved entropy encoding and decoding. An apparatus includes a video encoder (200) for encoding at least a block in a picture by transforming a residue of the block to obtain transform coefficients, quantizing the transform coefficients to obtain quantized transform coefficients, and entropy coding the quantized transform coefficients. The quantized transform coefficients are encoded using a flag to indicate that a current one of the quantized transform coefficients being processed is a last non-zero coefficient for the block having a value greater than or equal to a specified value.

Abstract: Techniques are proposed to improve temporal motion projection in video coding. Candidate reference frames available for use in temporal motion projection are sorted in processing order according to scores assigned based on estimates of the reference frames' suitability for prediction. Such estimates may be based on temporal distance between each candidate reference frame and that reference frame's prediction references. Estimates may be based, for each reference frame, based on an estimate of coding quality of a reference frame from which the respective candidate reference frame makes a prediction reference. Once sorted, the candidate reference frames may be processing in the sorting order to supply prediction data to a current frame that is to be coded from the candidate reference frames. Additionally, hardware friendly designs of motion field hole filling and motion vector smoothing operations are proposed.

Abstract: In an example method, a decoder accesses a bitstream representing video content, and parses one or more flexible coefficient position (FCP) syntax from the bitstream, where the one or more FCP syntax indicate one or more index values. The decoder further determines side information representing one or more characteristics of an encoded portion of the video content. The decoder interprets the one or more FCP syntax based on the side information, including determining a coefficient position with respect to the encoded portion of the video content based on the one or more index values and the side information. The decoder decodes the encoded portion of the video content according to the coefficient position.

Abstract: Methods and apparatus are provided for encoding and decoding binary sets using adaptive tree selection. In one exemplary encoding method embodiment, picture data is encoded for a block in a picture; in which one of a plurality of trees structures is selected to code a binary set of data for indicating coefficient significance for the block. In another exemplary encoding method embodiment, picture data is encoded for a block in a picture, in which one or more trees are used to encode a binary set of data for indicating significance for the block, the one or more trees each having a plurality of nodes, at least one of the nodes of the one or more trees being modified responsive to at least one parameter.

Abstract: Methods and apparatus are provided for adaptive motion vector candidate ordering for video encoding and decoding. An apparatus includes a video encoder (100) for encoding a block in a picture by selecting an order of motion vector predictor candidates for the block responsive to a characteristic available at both the video encoder and a corresponding decoder. The characteristic excludes a mode in which the block is partitioned.

Abstract: Video coding methods and apparatuses are provided. A set of two or more pictures is coded. The set includes at least a first picture coded with a first spatial resolution, and a second picture coded with a second spatial resolution different from the first spatial resolution. The set of two or more pictures is stored in a decoded picture buffer based on corresponding spatial resolutions. The set of two or more pictures stored in the decoded picture buffer is used as a set of reference pictures for coding one or more successive pictures subsequent to the set of two or more pictures. The set of two or more pictures is incorporated into a reference picture list that contains pictures with at least two different spatial resolutions.

Abstract: Methods and apparatus are provided for unified significance map coding. An apparatus includes a video encoder (400) for encoding transform coefficients for at least a portion of a picture. The transform coefficients are obtained using a plurality of transforms. One or more context sharing maps are generated for the transform coefficients based on a unified rule. The one or more context sharing maps are for providing at least one context that is shared among at least some of the transform coefficients obtained from at least two different ones of the plurality of transforms.

Abstract: Methods and apparatus are provided for improved entropy encoding and decoding. An apparatus includes a video encoder (200) for encoding at least a block in a picture by transforming a residue of the block to obtain transform coefficients, quantizing the transform coefficients to obtain quantized transform coefficients, and entropy coding the quantized transform coefficients. The quantized transform coefficients are encoded using a flag to indicate that a current one of the quantized transform coefficients being processed is a last non-zero coefficient for the block having a value greater than or equal to a specified value.