Abstract: Multi-directional image data often contains distortions of image content that cause problems when processed by video coders that are designed to process traditional, “flat” image content. Embodiments of the present disclosure provide techniques for coding multi-directional image data using such coders. For each pixel block in a frame to be coded, an encoder may transform reference picture data within a search window about a location of the input pixel block based on displacement respectively between the location of the input pixel block and portions of the reference picture within the search window. The encoder may perform a prediction search among the transformed reference picture data to identify a match between the input pixel block and a portion of the transformed reference picture and, when a match is identified, the encoder may code the input pixel block differentially with respect to the matching portion of the transformed reference picture.

Abstract: Chroma deblock filtering of reconstructed video samples may be performed to remove blockiness artifacts and reduce color artifacts without over-smoothing. In a first method, chroma deblocking may be performed for boundary samples of a smallest transform size, regardless of partitions and coding modes. In a second method, chroma deblocking may be performed when a boundary strength is greater than 0. In a third method, chroma deblocking may be performed regardless of boundary strengths. In a fourth method, the type of chroma deblocking to be performed may be signaled in a slice header by a flag. Furthermore, luma deblock filtering techniques may be applied to chroma deblock filtering.

Abstract: Techniques are disclosed for coding video data predictively based on predictions made from spherical-domain projections of input pictures to be coded and reference pictures that are prediction candidates. Spherical projection of an input picture and the candidate reference pictures may be generated. Thereafter, a search may be conducted for a match between the spherical-domain representation of a pixel block to be coded and a spherical-domain representation of the reference picture. On a match, an offset may be determined between the spherical-domain representation of the pixel block to a matching portion of the of the reference picture in the spherical-domain representation. The spherical-domain offset may be transformed to a motion vector in a source-domain representation of the input picture, and the pixel block may be coded predictively with reference to a source-domain representation of the matching portion of the reference picture.

Abstract: Embodiments of the present disclosure provide systems and methods for background concealment in a video conferencing session. In one exemplary method, a video stream may be captured and provided to a first terminal participating in a video chat session. A background element and a foreground element may be determined in the video stream. A border region may additionally be determined in the video stream. The border region may define a boundary between the foreground element and the background element. The background region may be modified based, at least in part, on video content of the border region. The modified video stream may be transmitted to a second terminal participating in the video conferencing session.

Abstract: During video coding, frame rate conversion (FRC) capabilities of a decoder may be estimated. Based on the estimated FRC capabilities, an encoder may select a frame rate for a video coding session and may alter a frame rate of source video to match the selected frame rate. Thereafter, the resultant video may be coded and output to a channel. By incorporating knowledge of a decoder's FRC capabilities as source video is being coded, an encoder may reduce the frame rate of source video opportunistically. Bandwidth that is conserved by avoiding coding of video data in excess of the selected frame rate may be directed to coding of the remaining video at a higher bitrate, which can lead to increased quality of the coding session as a whole.

Abstract: Techniques are disclosed for selecting deblocking filter parameters in a video decoding system. According to these techniques, a boundary strength parameter may be determined based, at least in part, on a bit depth of decoded video data. Activity of a pair of decoded pixel blocks may be classified based, at least in part, on the determined boundary strength parameter, and when a level of activity indicates that deblocking filtering is to be applied to the pair of pixel blocks, pixel block content at a boundary between the pair of pixel blocks may be filtered using filtering parameters derived at least in part based on the bit depth of the decoded video data. The filtering parameters may decrease strength with increasing bit depth of the decoded video data, which improves quality of the decoded video data.

Abstract: Methods and systems provide efficient sample adaptive offset (SAO) signaling by reducing a number of bits consumed for signaling SAO compared with conventional methods. In an embodiment, a single flag is used if a coding unit to a first scanning direction with respect to a given coding unit is off. In an embodiment, further bits may be saved if some neighboring coding units are not present, i.e. the given coding unit is an edge. For example, a flag may be skipped, e.g., not signaled, if the given coding unit does not have a neighbor. In an embodiment, a syntax element, one or more flags may signal whether SAO filtering is performed in a coding unit. Based on the syntax element, a merge flag may be skipped to save bits. In an embodiment, SAO syntax may be signaled at a slice level.

Abstract: Techniques for coding video data estimate depths of different elements within video content and identify regions within the video content based on the estimated depths. One of the regions may be assigned as an area of interest. Thereafter, video content of a region that is not an area of interest may be masked out and the resultant video content obtained from the masking may be coded. The coded video content may be transmitted to a channel. These techniques permit a coding terminal to mask out captured video content prior to coding in order to support coding policies that account for privacy interests or video composition features during a video coding session.

Abstract: Techniques are disclosed for managing memory allocations when coding video data according to multiple codec configurations. According to these techniques, devices may negotiate parameters of a coding session that include parameters of a plurality of different codec configurations that may be used during the coding session. A device may estimate sizes of decoded picture buffers for each of the negotiated codec configurations and allocate in its memory a portion of memory sized according to a largest size of the estimated decoded picture buffers. Thereafter, the devices may exchange coded video data. The exchange may involve decoding coded data of reference pictures and storing the decoded reference pictures in the allocated memory. During the coding session, the devices may toggle among the different negotiated codec configurations. As they do, reallocations of memory may be avoided.

Abstract: A video coder defines multiple fidelity regions in different spatial areas of a video sequence, each of which may have different fidelity characteristics. The coder may code the different representations in a common video sequence. Where prediction data crosses boundaries between the regions, interpolation may be performed to create like kind representations between prediction data and video content being coded.

Abstract: Video coding techniques are disclosed that can accommodate low bandwidth events and preserve visual quality, at least in areas of an image that have high significance to a viewer. Region(s) of interest may be identified from content of input frame that will be coded. Two representations of the input frame may be generated at different resolutions. A low resolution representation of the input frame may be coded according to predictive coding techniques in which a portion outside the region of interest is coded at higher quality than a portion inside the region of interest. A high resolution representation of the input frame may be coded according to predictive coding techniques in which a portion inside the region of interest is coded at higher quality than a portion outside the region of interest. Doing so preserves visual quality, at least in areas of the input image that correspond to the region of interest.

Abstract: Coding and decoding techniques are disclosed in which a plurality of coding parameter sets is transmitted between an encoder and a decoder, each of which is distinguishable from the others by a respective identifier. When a new frame of video is to be coded, an encoder may identify a coding parameter set to be applied during coding, it may code the new frame according to the identified coding parameter set, and it may transmit the coded frame to the decoder along with an identifier of the coding parameter set used during the coding. A plurality of coding parameter sets is persistent at an encoder and the decoder simultaneously.

Abstract: Video coders may perform perspective transformation of reference frames during coding in a manner that conserves processing resources. When a new input frame is available for coding, a camera position for the input frame may be estimated. A video coder may search for reference pictures having similar camera positions as the position of the input frame and, for each reference picture identified, the video coder may perform a prediction search to identify a reference picture that is the best prediction match for the input frame. Once the video coder identifies a reference picture to serve as a prediction source for the input frame, the video coder may derive a transform to match the reference frame data to the input frame data and may transform the reference picture accordingly. The video coder may code the input frame using the transformed reference picture as a prediction reference and may transmit coded frame data and the camera position of the input frame to a decoder.

Abstract: Techniques are disclosed for overcoming communication lag between interactive operations among devices in a streaming session. According to the techniques, a first device streaming video content to a second device and an annotation is entered to a first frame being displayed at the second device, which is communicated back to the first device. Responsive to a communication that identifies the annotation, a first device may identify an element of video content from the first frame to which the annotation applies and determine whether the identified element is present in a second frame of video content currently displayed at the first terminal. If so, the first device may display the annotation with the second frame in a location where the identified element is present. If not, the first device may display the annotation via an alternate technique.

Abstract: Techniques are disclosed for overcoming communication lag between interactive operations among devices in a streaming session. According to the techniques, a first device streaming video content to a second device and an annotation is entered to a first frame being displayed at the second device, which is communicated back to the first device. Responsive to a communication that identifies the annotation, a first device may identify an element of video content from the first frame to which the annotation applies and determine whether the identified element is present in a second frame of video content currently displayed at the first terminal. If so, the first device may display the annotation with the second frame in a location where the identified element is present. If not, the first device may display the annotation via an alternate technique.

Abstract: Techniques for coding video data are described that maintain high precision coding for low motion video content. Such techniques include determining whether a source video sequence to be coded has low motion content. When the source video sequence contains low motion content, the video sequence may be coded as a plurality of coded frames using a chain of temporal prediction references among the coded frames. Thus, a single frame in the source video sequence is coded as a plurality of frames. Because the coded frames each represent identical content, the quality of coding should improve across the plurality of frames. Optionally, the disclosed techniques may increase the resolution at which video is coded to improve precision and coding quality.

Abstract: Techniques are described for responding to changes in bandwidth that are available to transmit coded video data between an encoder and a decoder. When such changes in bandwidth occur, estimates may be derived of visual significance of coded video data that has not yet been transmitted and also video data that is next to be coded. These estimates may be compared to each other. When the estimated visual significance of the coded video data that has not yet been transmitted is greater than the estimated visual significance of the video data that is next to be coded, transmission of the coded video data that has not yet been transmitted may be prioritized over coding of the video data that is next to be coded.

Abstract: Methods are described for encoding and decoding blocks of image data using intra block copying (IBC). A source block for intra block copying is selected from a source region of a current image that is closer to the current block than a threshold, wherein the source region does not include a portion of the current image that is further from the current block than the threshold.

Abstract: A method of managing resources on a terminal includes determining a number of downloaded video streams active at the terminal, prioritizing the active video streams, assigning a decoding quality level to each active video stream based on a priority assignment for each active video stream, and apportioning reception bandwidth to each active video stream based on an assigned quality level of each active video stream.

Abstract: Techniques are disclosed for overcoming communication lag between interactive operations among devices in a streaming session. According to the techniques, a first device streaming video content to a second device and an annotation is entered to a first frame being displayed at the second device, which is communicated back to the first device. Responsive to a communication that identifies the annotation, a first device may identify an element of video content from the first frame to which the annotation applies and determine whether the identified element is present in a second frame of video content currently displayed at the first terminal. If so, the first device may display the annotation with the second frame in a location where the identified element is present. If not, the first device may display the annotation via an alternate technique.