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This specification is a draft of a potential new version of this specification and should not be referenced other than as a working draft.
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Abstract
This document specifies how to use HDR10+ metadata within [AV1] streams, including when carried in [CMAF].
1. Introduction
This document specifies how to use HDR10+ metadata within [AV1] streams, including when carried in [CMAF].
In this specification, HDR10+ Metadata is defined as data with the semantics defined in [SMPTE-ST-2094-40], using the syntax defined in [CTA-861]. HDR10+ Metadata OBU is defined as HDR10+ Metadata carried in an OBU of type ITU-T T.35 Metadata as defined in [AV1] and illustrated in Figure 1.
HDR10+ Metadata OBUs are not provided when show_frame=0. For non-layered streams, there is only one HDR10+ Metadata OBU per TU. For AV1 streams encoded with multiple layers, HDR10+ Metadata may apply to one or more layers but the details are out of scope of this version of the specification.
Figure 2. Example of OBU_Frame Structure
HDR10 Static Metadata (defined as MDCV, MaxCLL and MaxFALL) may be present.
2.2.3. Provision for Film Grain Processing
It is possible that some [AV1] coded bitstreams may contain both HDR10+ Metadata and film grain synthesis information. It is recommended that decoders in such scenarios perform the film grain synthesis prior to any HDR10+ Metadata processing.
An ISOBMFF file or CMAF AV1 track as defined in [AV1-ISOBMFF] that also conforms to this specification (i.e. that contains HDR10+ metadata OBUs and complies to the constraints from this specification) should use the brand cdm4 defined in [CTA-5001] in addition to the brand av01. If the brand cdm4 is used in conjunction with AV1 streams, the constraints defined in this specification shall be respected.
3.3. HTTP Streaming Constraints
The value of the codecs parameter for AV1 streams that is used when using HTTP streaming technologies shall remain unchanged when HDR10+ Metadata OBUs are included in the AV1 stream.
Information on this topic is found in the Wiki for this project.
Conformance
Conformance requirements are expressed with a combination of descriptive assertions and RFC 2119 terminology.
The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL”
in the normative parts of this document
are to be interpreted as described in RFC 2119.
However, for readability,
these words do not appear in all uppercase letters in this specification.
All of the text of this specification is normative
except sections explicitly marked as non-normative, examples, and notes. [RFC2119]
Examples in this specification are introduced with the words “for example”
or are set apart from the normative text with class="example", like this:
This is an example of an informative example.
Informative notes begin with the word “Note”
and are set apart from the normative text with class="note", like this:
