The embodiments relate to a method for writing, in a container file, two or more subpicture tracks; writing, in the container file, a base track, which is intended to be resolved into a video bitstream; indicating, in the base track, a layout of subpictures; writing, in the container file, a sample group description entry indicative of a first subpicture track or a group of subpicture tracks for each subpicture position in the layout of subpictures, wherein the first subpicture track includes the subpicture sequence for the respective subpicture position and wherein any track among the group of subpicture tracks includes a valid subpicture sequence for the respective subpicture position; and indicating in the container file, samples of the base track for which the sample group description entry is intended to be used for reconstructing the video bitstream. The embodiments also relate to a method for parsing, as well as technical equipment for implementing the method for writing and the method for parsing.

A method of encapsulating entities in a file, wherein the method comprises for at least one entity: generating a grouping data structure associated with at least one of the entities, and indicating that the at least one of the entities belong to a same group; encapsulating the grouping data structure and the entities in the file; wherein the grouping data structure is a proprietary grouping data structure comprising an universally unique identifier identifying the type of the proprietary grouping.

A video processing method is provided. In the method, a video bit stream is obtained. Configuration information of the video bit stream is determined. The configuration information includes reference image information. The reference image information indicates (i) whether a video track corresponding to the video bit stream includes a reference image and (ii) whether the video track requires reference to the reference image. The video bit stream and the configuration information are encapsulated to obtain the video track.

Methods and system for providing content are disclosed. One method can comprise receiving a request for data at a first time, wherein the data comprises a first time duration, determining a buffer size based upon the first time duration, and determining a playback window based upon the determined buffer size and the first time. The method can also comprise synchronizing presentation of content on a plurality of devices.

A processing load at a receiving side is reduced in a case where a plurality of classes of audio data is transmitted. A predetermined number of audio streams including coded data of a plurality of groups is generated and a container of a predetermined format having this predetermined number of audio streams is transmitted. Command information for creating a command specifying a group to be decoded from among the plurality of groups is inserted into the container and/or the audio stream. For example, a command insertion area for the receiving side to insert a command for specifying a group to be decoded is provided in at least one audio stream among the predetermined number of audio streams.

A device for retrieving media includes a memory configured to store media data of a media presentation; and one or more processors implemented in circuitry and configured to: retrieve a manifest file for a media presentation indicating that container parsing of media data of a bitstream can be started at a resync point of a segment of a representation of the media presentation, the resync point being at a position other than a start of the segment and representing a point at which the container parsing of the media data of the bitstream can be started; use the manifest file to form a request to retrieve the media data of the representation starting at the resync point; send the request to initiate retrieval of the media data of the media presentation starting at the resync point; and present the retrieved media data.

An example device for processing media data is configured to parse a bitstream including the media data, the bitstream being formatted according to Common Media Application Format (CMAF), detect, during the parsing, a file type (FTYP) value for a CMAF track file of the bitstream, determine that a CMAF header of the CMAF track file starts with the FTYP value, and process one or more CMAF fragments following the CMAF header of the CMAF track file. The device may additionally be configured to detect one or more segment type (STYP) values in the bitstream, determine that each of the one or more STYP values corresponds to a start of a respective one of the CMAF fragments, and process each of the CMAF fragments starting from the corresponding STYP value.

Embodiments herein provide techniques for signaling of priority information (e.g., priority ranking) and/or quality information in a timed metadata track associated with point cloud content. For example, embodiments include procedures for signaling of priority information and/or quality information in a timed metadata track to support viewport-dependent distribution of point cloud content, e.g., based on MPEG's International Organization for Standardization (ISO) Base Media File Format (ISOBMFF). In some embodiments, metadata samples of the timed metadata track may include priority information and/or quality information for a point cloud bounding box of a point cloud media presentation (e.g., for one or more point cloud objects in the point cloud bounding box). Other embodiments may be described and claimed.

A device for processing video data can be configured to receive a configuration record for decoding a bitstream of the video data, wherein the configuration record for the bitstream includes a toolset indication syntax element that includes information identifying, from a set of video decoding tools, tools that are required to decode the bitstream associated with the configuration record; based on the toolset indication syntax element, determine whether to retrieve the bitstream associated with the configuration record; and based on the determination to retrieve the bitstream associated with the configuration record, retrieve the bitstream and outputting the bitstream to a video decoder for decoding.

The techniques described herein relate to methods, apparatus, and computer readable media configured to access multimedia data comprising a hierarchical track structure comprising at least a first track at a first level of the hierarchical track structure comprising first media data, wherein the first media data comprises a first sequence of video media units, and a second track at a second level in the hierarchical track structure different than the first level of the first track, the second track comprising metadata specifying a re-timing derivation operation. Output video media units are generated according to the second track, comprising performing the re-timing derivation operation on the first sequence of video media units to modify a timing of the first sequence of video media units by removing one or more video media units associated with the re-timing derivation operation and/or shifting timing information of the first sequence of video media units.