The AV1SampleEntry sample entry identifies that the track contains AV1 Samples, and uses an AV1CodecConfigurationBox. Definition Sample Entry Type: av01Ĭontainer: Sample Description Box ('stsd') Parsers SHALL support the structures required by the iso6 brand and MAY support structures required by further ISOBMFF structural brands. It MAY indicate other brands not specified in this document provided that the associated requirements do not conflict with those given in this specification.It MAY indicate CMAF brands as specified in § 3 CMAF AV1 track format.It SHOULD indicate a structural ISOBMFF brand among the compatible brands array of the FileTypeBox, such as iso6.It SHALL contain at least one track using an AV1SampleEntry, possibly transformed by encryption as specified in § 4 Common Encryption.It SHALL have the av01 brand among the compatible brands array of the FileTypeBox. ![]() It SHALL conform to the normative requirements of.General Requirements & BrandsĪ file conformant to this specification satisfies the following: This section describes the basic data structures used to signal encapsulation of AV1 bitstreams in containers. A Key Frame Dependent Recovery Point is a frame with show_existing_frame set to 1 that refers to a previous Delayed Random Access Points. Delayed Random Access Points have the additional property that if a future Key Frame Dependent Recovery Point exists, all frames following that Key Frame Dependent Recovery Point can be decoded. Key Frames with the show_frame flag set to 0 are called Delayed Random Access Points. Key Frames with the show_frame flag set to 1 have the additional property that after decoding the Key Frame, all frames following the Key Frame in the bitstream can be decoded. Frames that cannot be decoded independently are of three categories: Inter Frames, Switch Frames, and frames with a show_existing_frame flag set to 1. Frames that can be decoded without dependencies to previous frames are of two categories: Key Frames and Intra-only Frames. ![]() A future version of the specification may do so.įrames carried in Temporal Units may have coding dependencies on frames carried previously in the same Temporal Unit or in previous Temporal Units. This version of storage in ISOBMFF supports the simple storage of scalable streams in a single track, but does not specify advanced tools for handling multi-track support, layer extraction, or other scalability related use cases. NOTE: The AV1 specification defines scalability features, allowing frames from multiple layers or operating points to be present in a single temporal unit. Some Temporal Units may contain multiple frames to be decoded but only one is presented. Each Temporal Unit is associated with a presentation time. Temporal Units are processed by a decoder in the order given by the bitstream. A future version of the specification may do so. NOTE: Tile List OBUs defined in the specification are not supported in the current version of this specification. Depending on its type, an OBU can carry configuration information, metadata, or coded video data. OBUs are made of a 1 or 2 bytes header, identifying in particular the type of OBU, followed by an optional length field and by an optional payload, whose presence and content depend on the OBU type. ![]() Bitstream features overviewĪn AV1 bitstream is composed of a sequence of OBUs, grouped into Temporal Units.
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