Abstract: Control data for a motion-constrained tile set (“MCTS”) indicates that inter-picture prediction processes within a specified set of tiles are constrained to reference only regions within the same set of tiles in previous pictures in decoding (or encoding) order. For example, a video encoder encodes multiple pictures partitioned into tiles to produce encoded data. The encoder outputs the encoded data along with control data (e.g., in a supplemental enhancement information message) that indicates that inter-picture prediction dependencies across tile set boundaries are constrained for a given tile set of one or more of the tiles. A video decoder or other tool receives the encoded data and MCTS control data, and processes the encoded data. Signaling and use of MCTS control data can facilitate region-of-interest decoding and display, transcoding to limit encoded data to a selected set of tiles, loss robustness, parallelism in encoding and/or decoding, and other video processing.

Abstract: Video frames of a higher-resolution chroma sampling format such as YUV 4:4:4 are packed into video frames of a lower-resolution chroma sampling format such as YUV 4:2:0 for purposes of video encoding. For example, sample values for a frame in YUV 4:4:4 format are packed into two frames in YUV 4:2:0 format. After decoding, the video frames of the lower-resolution chroma sampling format can be unpacked to reconstruct the video frames of the higher-resolution chroma sampling format. In this way, available encoders and decoders operating at the lower-resolution chroma sampling format can be used, while still retaining higher resolution chroma information. In example implementations, frames in YUV 4:4:4 format are packed into frames in YUV 4:2:0 format such that geometric correspondence is maintained between Y, U and V components for the frames in YUV 4:2:0 format.

Abstract: Methods and apparatus are described for performing data-intensive compute algorithms, such as fast massively parallel general matrix multiplication (GEMM), using a particular data format for both storing data to and reading data from memory. This data format may be utilized for arbitrarily-sized input matrices for GEMM implemented on a finite-size GEMM accelerator in the form of a rectangular compute array of digital signal processing (DSP) elements or similar compute cores. This data format solves the issue of double data rate (DDR) dynamic random access memory (DRAM) bandwidth by allowing both linear DDR addressing and single cycle loading of data into the compute array, avoiding input/output (I/O) and/or DDR bottlenecks.

Abstract: Innovations for signaling state of a decoded picture buffer (“DPB”) and reference picture lists (“RPLs”). In example implementations, rather than rely on internal state of a decoder to manage and update DPB and RPLs, state information about the DPB and RPLs is explicitly signaled. This permits a decoder to determine which pictures are expected to be available for reference from the signaled state information. For example, an encoder determines state information that identifies which pictures are available for use as reference pictures (optionally considering feedback information from a decoder about which pictures are available). The encoder sets syntax elements that represent the state information. In doing so, the encoder sets identifying information for a long-term reference picture (“LTRP”), where the identifying information is a value of picture order count least significant bits for the LTRB. The encoder then outputs the syntax elements as part of a bitstream.

Abstract: Innovations for category-prefixed data batching (“CPDB”) of entropy-coded data or other payload data for coded media data, as well as innovations for corresponding recovery of the entropy-coded data (or other payload data) formatted with CPDB. The CPDB can be used in conjunction with coding/decoding for video content, image content, audio content or another type of content. For example, after receiving coded media data in multiple categories from encoding units, a formatting tool formats payload data with CPDB, generating a batch prefix for a batch of the CPDB-formatted payload data. The batch prefix includes a category identifier and a data quantity indicator. The formatting tool outputs the CPDB-formatted payload data to a bitstream. At the decoder side, a formatting tool receives the CPDB-formatted payload data in a bitstream, recovers the payload data from the CPDB-formatted payload data, and outputs the payload data (e.g., to decoding units).

Abstract: A video decoding method is implemented by a computer having multiple parallel processing units. A stream of data elements is received, some of which encode video content. The stream comprises marker sequences, each marker sequence comprising a marker which does not encode video content. A known pattern of data elements occurs in each marker sequence. A respective part of the stream is supplied to each parallel processing unit. Each parallel processing unit processes the respective part of the stream, whereby multiple parts of the stream are processed in parallel, to detect whether any of the multiple parts matches the known pattern of data elements, thereby identifying the markers. The encoded video content is separated from the identified markers. The separated video content is decoded, and the decoded video content outputted on a display.

Abstract: Methods to switch between renditions of a video stream are generally described. In some examples, the methods may include encoding a video stream at a first image quality in a first rendition and a second, lower image quality in a second rendition. The methods may further include sending the first rendition to a recipient computing device. The methods may include receiving a request to switch from the first rendition to the second rendition. The methods may include determining that first indicator data of a first inter-coded frame indicates that the video stream can be switched to a lower image quality rendition at the first inter-coded frame. In some examples, the methods may further include sending the second rendition to the recipient computing device.

Abstract: Techniques are described that enable the use of variable bit rate (VBR) encoding for live content.

Abstract: Techniques are described for identifying pixel locations using a transformation function. A transformation function is identified based on the projection space of a 2D representation, and pixel locations are generated using the transformation function.

Abstract: Techniques are described for providing media presentations that include content originating from multiple sources in ways that are effectively transparent to end user devices. Manifest data provided to an end user device include a key encoded in the URL for each of the content fragments. The key encodes one or more interstitial periods of secondary content within the overall presentation of primary content. When a media server receives a content request from the end user device, the media server determines from the key encoded in the URL and the range of content requested whether the request corresponds to the primary content or the secondary content.

Abstract: Video content is protected using a digital rights management (DRM) mechanism, the video content having been previously encrypted and compressed for distribution, and also including metadata such as closed captioning data, which might be encrypted or clear. The video content is obtained by a system of a computing device, the metadata is extracted from the video content and provided to a video decoder, and the video content is provided to a secure DRM component. The secure DRM component decrypts the video content and provides the decrypted video content to a secure decoder component of a video decoder. As part of the decryption, the secure DRM component drops the metadata that was included in the obtained video content. However, the video decoder receives the extracted metadata in a non-protected environment and thus is able to provide the extracted metadata and the decoded video content to a content playback application.

Abstract: A system for delivering live streaming content based on accurate media data fragment size and duration. The system may include a client media player to receive a portion of a streaming media file (e.g., in an MP4 format), download a first sub-portion of the streaming media file including fragment-level metadata, and parse and analyze the fragment-level metadata to determine a size and duration of a current fragment of the media file. A media server may generate custom data identifying a size and duration of a current fragment of a media file. The media server may insert the custom data (e.g., as a custom header or unique packet identifier) and send the custom data to a client media player. The client media player may be configured to decode the custom data and determine the current fragment size and duration.

Abstract: Innovations for signaling state of a decoded picture buffer (“DPB”) and reference picture lists (“RPLs”). In example implementations, rather than rely on internal state of a decoder to manage and update DPB and RPLs, state information about the DPB and RPLs is explicitly signaled. This permits a decoder to determine which pictures are expected to be available for reference from the signaled state information. For example, an encoder determines state information that identifies which pictures are available for use as reference pictures (optionally considering feedback information from a decoder about which pictures are available). The encoder sets syntax elements that represent the state information. In doing so, the encoder sets identifying information for a long-term reference picture (“LTRP”), where the identifying information is a value of picture order count least significant bits for the LTRB. The encoder then outputs the syntax elements as part of a bitstream.

Abstract: Methods and apparatus are described for partitioning a manifest file to generate smaller manifest files for media content playback. A server partitions a manifest file prior to receipt of a request from a client or in response to a request from a client for a manifest for media content for a particular temporal range or subset of playback options.

Abstract: Video image stabilization provides better performance on a generic platform for computing devices by evaluating available multimedia digital signal processing components, and selecting the available components to utilize according to a hierarchy structure for video stabilization performance for processing parts of the video stabilization. The video stabilization has improved motion vector estimation that employs refinement motion vector searching according to a pyramid block structure relationship starting from a downsampled resolution version of the video frames. The video stabilization also improves global motion transform estimation by performing a random sample consensus approach for processing the local motion vectors, and selection criteria for motion vector reliability. The video stabilization achieves the removal of hand shakiness smoothly by real-time one-pass or off-line two-pass temporal smoothing with error detection and correction.

Abstract: Techniques are described for encoding noisy media content to improve its visual quality. Quantization parameters can be applied to residual coefficient matrices of portions of an image frame as a compression technique. To improve the visual quality of media content, the quantization parameters to be applied can be adjusted to fit within a range around a representative quantization parameter of all of the portions of the image frame.

Abstract: Techniques are described that enable virtual reality content to be delivered. These techniques include decoding reference frames of video content for non-viewed sections of the video content.

Abstract: Techniques are described for decoding portions of image frames for virtual reality (VR) media content. A field of view of a viewer within a VR environment can be determined and used to decode a portion of an image frame that provides image content for that portion. The other portions of the image frame that are not within the image frame can remain non-decoded when not in the visible field of view.

Abstract: This application relates to video encoding and decoding, and specifically to tools and techniques for using and providing supplemental enhancement information in bitstreams. Among other things, the detailed description presents innovations for bitstreams having supplemental enhancement information (SEI). In particular embodiments, the SEI message includes picture source data (e.g., data indicating whether the associated picture is a progressive scan picture or an interlaced scan picture and/or data indicating whether the associated picture is a duplicate picture). The SEI message can also express a confidence level of the encoder's relative confidence in the accuracy of this picture source data. A decoder can use the confidence level indication to determine whether the decoder should separately identify the picture as progressive or interlaced and/or a duplicate picture or honor the picture source scanning information in the SEI as it is.

Abstract: Techniques are described by which multiple, independently encoded video streams may be combined into a single decodable video stream. These techniques take advantage of existing features of commonly used video codecs that support the independent encoding of different regions of an image frame (e.g., H.264 slices or HEVC tiles). Instead of including different parts of the same image, each region corresponds to the encoded image data of the frames of one of the independent video streams.