The registration is not intended to include any information on whether a
codec format is encumbered by intellectual property claims. Implementers and
authors are advised to seek appropriate legal counsel in this matter if they
intend to implement or use a specific codec format. Implementers of
WebCodecs are not required to support the HEVC / H.265 codec.
This registration is non-normative.
Status of this document
This section describes the status of this document at the time of its publication. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at https://www.w3.org/TR/.
Feedback and comments on this specification are welcome. GitHub Issues are preferred for discussion on this specification. Alternatively, you can send comments to the Media Working Group’s mailing-list, email@example.com (archives).
This draft highlights some of the pending issues that are still to be discussed in the working group.
No decision has been taken on the outcome of these issues including whether they are valid.
NOTE: "annexb" format is described in greater detail by [ITU-T-REC-H.265],
Annex B. This format is commonly used in live-streaming applications, where
including the VPS, SPS, and PPS data periodically allows users to easily
start from the middle of the stream.
4. EncodedVideoChunk type
If an EncodedVideoChunk's [[type]] is key, and the bitstream is in hevc format, then the EncodedVideoChunk is expected
to contain a base layer primary coded picture that is an instantaneous decoding
refresh (IDR), clean random access (CRA), or broken link access (BLA) picture.
If an EncodedVideoChunk's [[type]] is key, and the bitstream is in annexb format, then the EncodedVideoChunk is
expected to contain both a base layer coded picture that is an instantaneous
decoding refresh (IDR), clean random access (CRA), or broken link access (BLA)
picture, and all parameter sets necessary to decode all video data
NAL units in the EncodedVideoChunk.
The HevcBitstreamFormat determines the location of HEVC parameter sets, and
mechanisms for packaging the bitstream.
Parameter sets are included periodically throughout the bitstream.
NOTE: This format is described in greater detail by [ITU-T-REC-H.265],
Annex B. This format is commonly used in live-streaming applications,
where including the parameter set data periodically allows users to
easily start from the middle of the stream.
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
This is an example of an informative example.
Informative notes begin with the word “Note”
and are set apart from the normative text
Note, this is an informative note.
Requirements phrased in the imperative as part of algorithms
(such as "strip any leading space characters"
or "return false and abort these steps")
are to be interpreted with the meaning of the key word
("must", "should", "may", etc)
used in introducing the algorithm.
Conformance requirements phrased as algorithms or specific steps
can be implemented in any manner,
so long as the end result is equivalent.
In particular, the algorithms defined in this specification
are intended to be easy to understand
and are not intended to be performant.
Implementers are encouraged to optimize.