VP9 WebCodecs Registration W3C Group Draft Note , 14 May 2025 More details about this document This version: https://www.w3.org/TR/2025/DNOTE-webcodecs-vp9-codec-registration-20250514/ Latest published version: https://www.w3.org/TR/webcodecs-vp9-codec-registration/ Editor's Draft: https://w3c.github.io/webcodecs/vp9_codec_registration.html Previous Versions: https://www.w3.org/TR/2025/DNOTE-webcodecs-vp9-codec-registration-20250212/ History: https://www.w3.org/standards/history/webcodecs-vp9-codec-registration/ Feedback: GitHub Editors: Paul Adenot ( Mozilla ) Eugene Zemtsov ( Google LLC ) Former Editors: Bernard Aboba ( Microsoft Corporation ) Chris Cunningham ( Google Inc. ) Participate: Git Repository. File an issue. Version History: https://github.com/w3c/webcodecs/commits Copyright © 2025 World Wide Web Consortium . W3C ® liability , trademark and permissive document license rules apply. 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, (4) the values of EncodedVideoChunk [[type]] , and (5) the codec-specific extensions to VideoEncoderEncodeOptions . 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. 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 standards and drafts 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 protected] ( 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. The W3C Patent Policy does not carry any licensing requirements or commitments on this document. This document is governed by the 03 November 2023 W3C Process Document . Table of Contents 1 Fully qualified codec strings 2 EncodedVideoChunk data 3 VideoDecoderConfig description 4 EncodedVideoChunk type 5 VideoEncoderEncodeOptions extensions 5.1 VideoEncoderEncodeOptionsForVp9 6 Privacy Considerations 7 Security Considerations Conformance Document conventions Index Terms defined by this specification Terms defined by reference References Normative References Informative References IDL Index 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 The 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. VideoEncoderEncodeOptions extensions partial dictionary VideoEncoderEncodeOptions { VideoEncoderEncodeOptionsForVp9 vp9 ; }; vp9 , of type VideoEncoderEncodeOptionsForVp9 Contains codec specific encode options for the [VP9] codec. 5.1. VideoEncoderEncodeOptionsForVp9 dictionary VideoEncoderEncodeOptionsForVp9 { unsigned short ? quantizer ; }; quantizer , of type unsigned short , nullable Sets per-frame quantizer value. In [VP9] the quantizer threshold can be varied from 0 to 63 6. Privacy Considerations Please refer to the section Privacy Considerations in [WEBCODECS] . 7. Security Considerations Please refer to the section Security Considerations in [WEBCODECS] . Conformance 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. Index Terms defined by this specification quantizer , in § 5.1 VideoEncoderEncodeOptionsForVp9 , in § 5.1 vp9 , in § 5 Terms defined by reference [WEBCODECS] defines the following terms: "key" EncodedVideoChunk VideoEncoderEncodeOptions [[internal data]] [[type]] description [WEBIDL] defines the following terms: unsigned short References Normative References [RFC2119] S. Bradner. Key words for use in RFCs to Indicate Requirement Levels . March 1997. Best Current Practice. URL: https://datatracker.ietf.org/doc/html/rfc2119 [WEBCODECS] Paul Adenot; Eugene Zemtsov. WebCodecs . 17 April 2025. WD. URL: https://www.w3.org/TR/webcodecs/ [WEBIDL] Edgar Chen; Timothy Gu. Web IDL Standard . Living Standard. URL: https://webidl.spec.whatwg.org/ Informative References [VP9] VP9 Bitstream & Decoding Process Specification . URL: https://storage.googleapis.com/downloads.webmproject.org/docs/vp9/vp9-bitstream-specification-v0.6-20160331-draft.pdf [VP9-ISOBMFF] VP Codec ISO Media File Format Binding . URL: https://github.com/webmproject/vp9-dash/blob/master/VPCodecISOMediaFileFormatBinding.md [WEBCODECS-CODEC-REGISTRY] Paul Adenot; Bernard Aboba. WebCodecs Codec Registry . 9 September 2024. DRY. URL: https://www.w3.org/TR/webcodecs-codec-registry/ IDL Index partial dictionary VideoEncoderEncodeOptions { VideoEncoderEncodeOptionsForVp9 vp9 ; }; dictionary VideoEncoderEncodeOptionsForVp9 { unsigned short ? quantizer ; };