Abstract
This registration is entered into the [webcodecs-codec-registry].
It describes, for VP9, the (1) fully qualified codec strings,
(2) the codec-specific EncodedVideoChunk [[internal data]] bytes, (3) the VideoDecoderConfig.description bytes, and (4) the values of EncodedVideoChunk [[type]].
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 VP9 codec.
This registration is non-normative.
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, public-media-wg@w3.org (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.
This document was published by the Media Working Group as a Group Draft Note using the Note
track.
Group Draft Notes are not endorsed
by W3C nor its Members.
This is a draft document and may be updated, replaced or obsoleted by other documents at any time.
It is inappropriate to cite this document as other than work in progress.
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This document is governed by the 2 November 2021 W3C Process Document.
1. Fully qualified codec strings
The codec string begins with the prefix "vp09.", followed by a variable length
suffix as described in the "Codecs Parameter String" Section of [VP9-ISOBMFF].
2. EncodedVideoChunk data
EncodedVideoChunk [[internal data]] is expected to be
a frame as described in Section 6 of [VP9].
3. VideoDecoderConfig description
VideoDecoderConfig.description is not used for this codec.
4. EncodedVideoChunk type
If an EncodedVideoChunk's [[type]] is key, then the EncodedVideoChunk is expected to
contain a frame with a frame_type of KEY_FRAME as defined in Section
7.2 of [VP9].
5. Privacy and Security Considerations
Please refer to the Privacy Considerations and Security Considerations sections in [WEBCODECS].
Document conventions
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:
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.