From a270f0f3adafcea640cc8b2834eadce4f671a54e Mon Sep 17 00:00:00 2001 From: Chris Cunningham Date: Tue, 23 Feb 2021 14:47:11 -0800 Subject: [PATCH 1/3] Establish codec registry and avc registration. This moves codec-specific defintions / descriptions into a registry. I've also added some text to the main document to clarify that support for any given codec is not required. --- .gitignore | 6 +- Makefile | 50 ++++++-- avc_codec_registration.src.html | 168 +++++++++++++++++++++++++ codec_registry.src.html | 172 ++++++++++++++++++++++++++ index.src.html | 210 ++++++++++---------------------- 5 files changed, 449 insertions(+), 157 deletions(-) create mode 100644 avc_codec_registration.src.html create mode 100644 codec_registry.src.html diff --git a/.gitignore b/.gitignore index bf2734b9..0adf4116 100644 --- a/.gitignore +++ b/.gitignore @@ -1,5 +1,7 @@ -out/ -index.html +avc_codec_registration.html +codec_registry.html deploy_key deploy_key.pub +index.html +out/ diff --git a/Makefile b/Makefile index 4debbecd..46c82d50 100644 --- a/Makefile +++ b/Makefile @@ -1,9 +1,17 @@ SHELL=/bin/bash -local: index.src.html +local: local-index local-codec-registry local-avc-codec-registration + +local-index: index.src.html bikeshed --die-on=warning spec index.src.html index.html -index.html: index.src.html +local-codec-registry: codec_registry.src.html + bikeshed --die-on=warning spec codec_registry.src.html codec_registry.html + +local-avc-codec-registration: avc_codec_registration.src.html + bikeshed --die-on=warning spec avc_codec_registration.src.html avc_codec_registration.html + +remote-index: index.src.html @ (HTTP_STATUS=$$(curl https://api.csswg.org/bikeshed/ \ --output index.html \ --write-out "%{http_code}" \ @@ -16,14 +24,38 @@ index.html: index.src.html exit 22 \ ); -remote: index.html +remote-codec-registry: codec_registry.src.html + @ (HTTP_STATUS=$$(curl https://api.csswg.org/bikeshed/ \ + --output codec_registry.html \ + --write-out "%{http_code}" \ + --header "Accept: text/plain, text/html" \ + -F die-on=warning \ + -F file=@codec_registry.src.html) && \ + [[ "$$HTTP_STATUS" -eq "200" ]]) || ( \ + echo ""; cat codec_registry.html; echo ""; \ + rm -f codec_registry.html; \ + exit 22 \ + ); + +remote-avc-codec-registration: avc_codec_registration.src.html + @ (HTTP_STATUS=$$(curl https://api.csswg.org/bikeshed/ \ + --output avc_codec_registration.html \ + --write-out "%{http_code}" \ + --header "Accept: text/plain, text/html" \ + -F die-on=warning \ + -F file=@avc_codec_registration.src.html) && \ + [[ "$$HTTP_STATUS" -eq "200" ]]) || ( \ + echo ""; cat avc_codec_registration.html; echo ""; \ + rm -f avc_codec_registration.html; \ + exit 22 \ + ); + + +remote: remote-index remote-codec-registry remote-avc-codec-registration -ci: index.src.html +ci: index.src.html codec_registry.src.html avc_codec_registration.src.html mkdir -p out make remote mv index.html out/index.html - -clean: - rm index.html - rm -rf out - + mv codec_registry.html out/codec_registry.html + mv avc_codec_registration.html out/avc_codec_registration.html diff --git a/avc_codec_registration.src.html b/avc_codec_registration.src.html new file mode 100644 index 00000000..bced1c6c --- /dev/null +++ b/avc_codec_registration.src.html @@ -0,0 +1,168 @@ +
+Title: AVC (H.264) WebCodecs Registration
+Repository: wicg/web-codecs
+Status: CG-DRAFT
+Shortname: web-codecs-avc-codec-registration
+Level: none
+Group: wicg
+ED: none
+Editor: Chris Cunningham, w3cid 114832, Google Inc. https://google.com/
+Editor: Paul Adenot, w3cid 62410, Mozilla https://www.mozilla.org/
+Editor: Bernard Aboba, w3cid 65611, Microsoft Corporation https://www.microsoft.com/
+Boilerplate: omit conformance
+
+Abstract: This registration is entered into the [[WebCodecs-Codec-Registry]]. It
+    describes, for AVC (H.264), the (1) fully qualified codec strings, (2) the
+    {{WebCodecs/VideoDecoderConfig.description}} bytes, and (3) the
+    codec-sepcific extensions to the {{WebCodecs/VideoEncoderConfig}}.
+
+    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 AVC / H.264 codec.
+
+    This registration is non-normative.
+
+Markup Shorthands:css no, markdown yes, dfn yes
+!Participate: Git Repository.
+!Participate: File an issue.
+!Version History: https://github.com/wicg/web-codecs/commits
+
+ +
+spec: web-codecs; for: WebCodecs; urlPrefix: https://wicg.github.io/web-codecs/#
+    type: attribute
+        text: VideoDecoderConfig.description; url: dom-videodecoderconfig-description
+    type: interface
+        text: EncodedVideoChunk; url: encodedvideochunk
+        text: VideoEncoder; url: videoencoder
+    type: dictionary
+        text: VideoEncoderConfig; url: video-encoder-config
+        text: VideoDecoderConfig; url: dictdef-videodecoderconfig
+
+ +
+{
+  "WebCodecs-Codec-Registry": {
+      "href": "https://wicg.github.io/web-codecs/codec_registry.html",
+      "title": "WebCodecs Codec Registry",
+      "publisher": "WICG"
+  },
+  "ITU-T-REC-H.264": {
+    "href": "https://www.itu.int/rec/T-REC-H.264",
+    "title": "H.264 : Advanced video coding for generic audiovisual services",
+    "publisher": "ITU",
+    "date": "June 2019"
+  }
+}
+
+ +Fully qualified codec strings {#fully-qualified-codec-strings} +============================================================== + +The codec string must begin with the prefix "avc1.", and contain a suffix of 6 +characters as described in Section 3.4 of [[rfc6381]]. + +NOTE: The common "avc3." prefix is intentionally not included. This prefix does + not signal a material difference to decoder inputs, so it is omitted for + simplification. For the purposes of this registration, authors should simply + map "avc3." to "avc1.". + +VideoDecoderConfig description {#videodecoderconfig-description} +================================================================ + +A {{WebCodecs/VideoDecoderConfig.description}} may or may not be required by the +AVC codec depending on the bitstream format of the AVC content to be decoded. + +If the {{WebCodecs/VideoDecoderConfig.description}} includes an +`AVCDecoderConfigurationRecord`, as defined by [[iso14496-15]], section 5.3.3.1, +it will be assumed that the bitstream is in "avc" format. + +NOTE: This format is commonly used in .MP4 files, where the player generally has + random access to the media data. + +If the {{WebCodecs/VideoDecoderConfig.description}} is not provided, it will be +assumed that the bitstream is in “annexb” format. + +NOTE: "annexb" format is described in greater detail by [[ITU-T-REC-H.264]], + Annex B. This format is commonly used in live-streaming applications, where + including the SPS and PPS data periodically allows users to easily start + from the middle of the stream. + +VideoEncoderConfig extensions {#videoencoderconfig-extensions} +============================================================== + +
+
+/* partial */ dictionary VideoEncoderConfig {
+  AvcEncoderConfig avc;
+};
+
+
+ +
+
avc
+
+ Contains codec specific configuration options for the AVC (H.264) codec. +
+
+ +AvcEncoderConfig {#avc-encoder-config} +-------------------------------------- +
+
+dictionary AvcEncoderConfig {
+  AvcBitstreamFormat format = "avc";
+};
+
+
+ +
+
format
+
+ Configures the format of output {{WebCodecs/EncodedVideoChunk}}s. See + {{AvcBitstreamFormat}}. +
+
+ +AvcBitstreamFormat {#avc-bitstream-format} +------------------------------------------ +
+
+enum AvcBitstreamFormat {
+  "annexb",
+  "avc",
+};
+
+
+ +The {{AvcBitstreamFormat}} determines the location of AVC Sequence Parameter +Set (SPS) and Picture Parameter Set (PPS) data, and mechanisms for packaging +the bitstream. + +SPS and PPS are described in greater detail in sections G.3.41 and G.3.55 of +[[ITU-T-REC-H.264]]. + +
+
annexb
+
+ SPS and PPS data are included periodically throughout the bitstream. + + NOTE: This format is described in greater detail by [[ITU-T-REC-H.264]], + Annex B. This format is commonly used in live-streaming applications, + where including the SPS and PPS data periodically allows users to easily + start from the middle of the stream. +
+
avc
+
+ SPS and PPS data are not included in the bitstream and are instead emitted + via the {{WebCodecs/VideoEncoder}} [[output callback]] as the + {{WebCodecs/VideoDecoderConfig.description}} of the + {{WebCodecs/VideoDecoderConfig}}. + output_config. + + NOTE: This format is described in greater detail by [[iso14496-15]], + section 5.3.3.1. This format is commonly used in .MP4 files, where the + player generally has random access to the media data. +
\ No newline at end of file diff --git a/codec_registry.src.html b/codec_registry.src.html new file mode 100644 index 00000000..392db7ad --- /dev/null +++ b/codec_registry.src.html @@ -0,0 +1,172 @@ +
+Title: WebCodecs Codec Registry
+Repository: wicg/web-codecs
+Status: CG-DRAFT
+Shortname: web-codecs-codec-registry
+Level: none
+Group: wicg
+ED: none
+Editor: Chris Cunningham, w3cid 114832, Google Inc. https://google.com/
+Editor: Paul Adenot, w3cid 62410, Mozilla https://www.mozilla.org/
+Editor: Bernard Aboba, w3cid 65611, Microsoft Corporation https://www.microsoft.com/
+
+Boilerplate: omit conformance
+
+Abstract: This registry is intended to enhance interoperability among
+    implementations and users of [[WebCodecs]]. In particular, this
+    registry provides the means to identify and avoid collisions among codec
+    strings and provides a mechanism to define codec-specific members of
+    [[WebCodecs]] codec configuration dictionaries.
+
+    This registry is not intended to include any information on whether a codec
+    format is encumbered by intellectual property claims. Implementers and
+    users 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 any particular codec nor registry
+    entry.
+
+    This registry is non-normative.
+
+Markup Shorthands:css no, markdown yes, dfn yes
+!Participate: Git Repository.
+!Participate: File an issue.
+!Version History: https://github.com/wicg/web-codecs/commits
+
+ +
+spec: web-codecs; for: WebCodecs; urlPrefix: https://wicg.github.io/web-codecs/#
+    type: attribute
+        text: AudioDecoderConfig.description; url: dom-audiodecoderconfig-description
+        text: VideoDecoderConfig.description; url: dom-videodecoderconfig-description
+        text: VideoEncoderConfig; url: video-encoder-config
+        text: AudioEncoderConfig; url: audio-encoder-config
+
+ +
+{
+  "WebCodecs": {
+      "href": "https://wicg.github.io/web-codecs/",
+      "title": "WebCodecs",
+      "publisher": "WICG"
+  },
+  "AVC-REGISTRATION": {
+      "href": "https://wicg.github.io/web-codecs/avc_codec_registration.html",
+      "title": "AVC (H.264) WebCodecs Registration",
+      "publisher": "WICG"
+  }
+}
+
+ +Organization {#organization} +============================ + +This registry maintains a mapping between codec strings and definitions for (1) +fully qualified codec string values, (2) codec-specific values for +{{WebCodecs/VideoDecoderConfig.description}} and +{{WebCodecs/AudioDecoderConfig.description}}, and (3) codec-specific members of +the {{WebCodecs/VideoEncoderConfig}} and {{WebCodecs/AudioEncoderConfig}} +dictionaries. + +Registration Entry Requirements {#registration-entry-requirements} +================================================================== + +1. Each entry must include a unique codec string and a common name string. +2. If the codec string contains a fixed prefix with variable suffix values, the + suffix must be represented by an asterisk and the registration must link to + a public specification describing how to fully qualify the variable portion + of the string. +3. If the described codec requires that codec-specific bytes be provided as part + of the {{WebCodecs/VideoDecoderConfig.description}} or the + {{WebCodecs/AudioDecoderConfig.description}}, the registration must link to + a public specification describing how to populate these fields. +4. If the {{WebCodecs/AudioEncoderConfig}} or {{WebCodecs/VideoEncoderConfig}} + dictionaries are extended with members specific to the described codec, the + registration must link to a public specification describing how to populate + these fields. +4. Candidate entries must be announced by filing an issue in the + [WebCodecs GitHub issue tracker](https://github.com/wicg/web-codecs/issues/) + so they can be discussed and evaluated for compliance before being added to + the registry. + +Audio Codec Registry {#audio-codec-registry} +============================================ + +ISSUE: Several registrations contain TODOs which should be replaced with links + to public specifications covering the mentioned definitions. + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
**codec string****common name****public specification**
flacFlacTODO (AudioDecoderConfig.description)
mp3MP3N/A
mp4a.*AACTODO (string + AudioDecoderConfig.description)
opusOpusTODO (AudioDecoderConfig.description)
vorbisVorbisTODO (AudoDecoderConfig.description)
ulawPCM u-lawN/A
alawPCM a-lawN/A
+ +Video Codec Registry {#video-codec-registry} +============================================ + +ISSUE: Several registrations contain TODOs which should be replaced with links + to public specifications covering the mentioned definitions. + + + + + + + + + + + + + + + + + + + + + + + + + + + +
**codec string****common name****specification**
av01.*AV1TODO (string + VideoDecoderConfig.description)
avc1.*AVC / H.264[AVC (H.264) WebCodecs Registration](avc_codec_registration.html) [[AVC-REGISTRATION]]
vp8VP8N/A
vp09.*VP9TODO (string)
diff --git a/index.src.html b/index.src.html index 163ba06a..e9c50fc7 100644 --- a/index.src.html +++ b/index.src.html @@ -10,9 +10,14 @@ Editor: Paul Adenot, w3cid 62410, Mozilla https://www.mozilla.org/ Editor: Bernard Aboba, w3cid 65611, Microsoft Corporation https://www.microsoft.com/ -Abstract: This specification defines interfaces for encoding and decoding audio -Abstract: and video. It also includes an interface for retrieving raw video -Abstract: frames from MediaStreamStracks. +Abstract: This specification defines interfaces to codecs for encoding and + decoding of audio and video. + + This specification does not specify or require any particular codec or + method of encoding or decoding. The purpose of this specification is to + provide JavaScript interfaces to implementations of existing codec + technology developed elsewhere. Implementers may support any combination of + codecs or none at all. Markup Shorthands:css no, markdown yes, dfn yes !Participate: Git Repository. @@ -65,6 +70,16 @@ type: attribute; text: powerEfficient; url: dom-mediacapabilitiesinfo-powerefficient +
+{
+  "CODEC-REGISTRY": {
+      "href": "https://wicg.github.io/web-codecs/codec_registry.html",
+      "title": "WebCodecs Codec Registry",
+      "publisher": "WICG"
+  }
+}
+
+ Definitions {#definitions} ========================== @@ -90,18 +105,6 @@ objects. Such resources may be quickly exhuasted and should be released immediately when no longer in use. -: Advanced Video Coding (AVC) -:: Also known as H.264. Refers to the methods of video compression as defined by - [[!iso14496-10]]. - -: Picture Parameter Set (PPS) -:: A set of parameters describing AVC coded pictures as defined by - [[!iso14496-10]]. - -: Sequence Parameter Set (SPS) -:: A set of parameters describing a sequence of AVC coded video as - defined by [[!iso14496-10]]. - Codec Processing Model {#codec-processing-model} ================================================ @@ -110,11 +113,11 @@ This section is non-normative. -The codec interfaces defined by the specification designed such that new codec -tasks may be scheduled while previous tasks are still pending. For example, web -authors may call `decode()` without waiting for a previous `decode()` to -complete. This is achieved by offloading underlying codec tasks to a separate -thread for parallel execution. +The codec interfaces defined by the specification are designed such that new +codec tasks may be scheduled while previous tasks are still pending. For +example, web authors may call `decode()` without waiting for a previous +`decode()` to complete. This is achieved by offloading underlying codec tasks to +a separate thread for parallel execution. This section describes threading behaviors as they are visible from the perspective of web authors. Implementers may choose to use more or less threads @@ -247,9 +250,10 @@ [=Enqueues a control message=] to configure the audio decoder for decoding chunks as described by |config|. - NOTE: Authors should first check support by calling - {{AudioDecoder/isConfigSupported()}} with |config| to avoid error paths - in the steps below. + NOTE: This method will trigger a {{NotSupportedError}} if the user agent + does not support |config|. Authors should first check support by calling + {{AudioDecoder/isConfigSupported()}} with |config|. User agents are not + required to support any particular codec type or configuration. When invoked, run these steps: 1. If |config| is not a [=valid AudioDecoderConfig=], throw a @@ -475,9 +479,10 @@ [=Enqueues a control message=] to configure the video decoder for decoding chunks as described by |config|. - NOTE: Authors should first check support by calling - {{VideoDecoder/isConfigSupported()}} with |config| to avoid error paths - in the steps below. + NOTE: This method will trigger a {{NotSupportedError}} if the user agent + does not support |config|. Authors should first check support by calling + {{VideoDecoder/isConfigSupported()}} with |config|. User agents are not + required to support any particular codec type or configuration. When invoked, run these steps: 1. If |config| is not a [=valid VideoDecoderConfig=], throw a @@ -721,9 +726,10 @@ [=Enqueues a control message=] to configure the audio encoder for decoding chunks as described by |config|. - NOTE: Authors should first check support by calling - {{AudioEncoder/isConfigSupported()}} with |config| to avoid error paths - in the steps below. + NOTE: This method will trigger a {{NotSupportedError}} if the user agent + does not support |config|. Authors should first check support by calling + {{AudioEncoder/isConfigSupported()}} with |config|. User agents are not + required to support any particular codec type or configuration. When invoked, run these steps: 1. If |config| is not a [=valid AudioEncoderConfig=], throw a @@ -971,9 +977,10 @@ [=Enqueues a control message=] to configure the video encoder for decoding chunks as described by |config|. - NOTE: Authors should first check support by calling - {{VideoEncoder/isConfigSupported()}} with |config| to avoid error paths - in the steps below. + NOTE: This method will trigger a {{NotSupportedError}} if the user agent + does not support |config|. Authors should first check support by calling + {{VideoEncoder/isConfigSupported()}} with |config|. User agents are not + required to support any particular codec type or configuration. When invoked, run these steps: 1. If |config| is not a [=valid VideoEncoderConfig=], throw a @@ -1131,7 +1138,9 @@ NOTE: This includes supplying the {{VideoDecoderConfig/description}} to describe codec - specific "extradata" like the avcC bytes for AVC. + specific "extradata", the use of which may be further + described in codec registrations listed in the + [[CODEC-REGISTRY]]. 3. If |output_config| and {{VideoEncoder/[[active output config]]}} are equal dictionaries, set |output_config| to null. Otherwise, set {{VideoEncoder/[[active output config]]}} to |output_config|. @@ -1317,63 +1326,24 @@ Codec String{#config-codec-string} ---------------------------------------------------- -In other media specifications, codec strings historically accompanied a - [=MIME type=] as the "codecs=" parameter - ({{MediaSource/isTypeSupported()}}, {{HTMLMediaElement/canPlayType()}}) - [[RFC6381]]. In this specification, encoded media is not containerized; hence, - only the value of the codecs parameter is accepted. +A codec string describes a given codec format to be used for encoding or +decoding. A valid codec string must meet the following conditions. 1. Is valid per the relevant codec specification (see examples below). - 2. It describes a single codec. - -NOTE: Not a comma separated list. - 3. It is unambiguous about codec profile and level for codecs that define these concepts. +NOTE: In other media specifications, codec strings historically accompanied a + [=MIME type=] as the "codecs=" parameter + ({{MediaSource/isTypeSupported()}}, {{HTMLMediaElement/canPlayType()}}) + [[RFC6381]]. In this specification, encoded media is not containerized; + hence, only the value of the codecs parameter is accepted. -
- NOTE: There is no unified specification for codec strings. Each codec has its - own unique string format, specified by the authors of the codec. Relevant - specifications include: - - * h264, aac - [[RFC6381]] - * vp9 - - - https://www.webmproject.org/vp9/mp4/#codecs-parameter-string - - * hevc - - - ISO IEC 14496-15 dated 2012 or newer in the Annex E.3 - - * av1 - - - https://aomediacodec.github.io/av1-isobmff/#codecsparam - - -
- -
-Valid examples include:
- * 'vp8' - * 'vp09.00.10.08' - * 'avc1.4D401E', - * 'opus', - * 'mp4a.40.2', - * 'flac' - -Invalid examples include:
- * 'video/webm; codecs="vp8"' (invalid to supply full mimetype; valid as just - 'vp8')
- * 'codecs="opus"' (invalid to include codecs= prefix)
- * ‘flac,vorbis’ (describes more than one codec)
- * ‘vp9’ (ambiguous about profile and level)
- * 'video/mp4' (describes a container, not a codec)
- -
- +The format and semantics for codec strings are defined by codec registrations +listed in the [[CODEC-REGISTRY]]. A compliant implementation may support any +combination of codec registrations or none at all. AudioDecoderConfig{#audio-decoder-config} ----------------------------------------- @@ -1407,7 +1377,9 @@
A sequence of codec specific bytes, commonly known as extradata. - NOTE: For example, the vorbis "code book". + NOTE: The registrations in the [[CODEC-REGISTRY]] describe whether/how to + populate this sequence, corresponding to the provided + {{AudioDecoderConfig/codec}}.
@@ -1456,7 +1428,9 @@
A sequence of codec specific bytes, commonly known as extradata. - NOTE: Examples include the VP9 vpcC bytes or the AVC avcC bytes. + NOTE: The registrations in the [[CODEC-REGISTRY]] may describe whether/how + to populate this sequence, corresponding to the provided + {{VideoDecoderConfig/codec}}.
codedWidth
@@ -1527,6 +1501,9 @@ +NOTE: Codec-specific extensions to {{AudioEncoderConfig}} may be defined by the + registrations in the [[CODEC-REGISTRY]]. + To check if an {{AudioEncoderConfig}} is a valid AudioEncoderConfig, run these steps: 1. If {{AudioEncoderConfig/codec}} is not a valid codec string, return @@ -1557,12 +1534,13 @@ unsigned long displayWidth; unsigned long displayHeight; HardwareAcceleration hardwareAcceleration = "allow"; - - AvcEncoderConfig avc; }; +NOTE: Codec-specific extensions to {{VideoEncoderConfig}} may be defined by the + registrations in the [[CODEC-REGISTRY]]. + To check if a {{VideoEncoderConfig}} is a valid VideoEncoderConfig, run these steps: 1. If {{VideoEncoderConfig/codec}} is not a valid codec string, return @@ -1571,8 +1549,6 @@ = 0, return `false`. 3. If {{VideoEncoderConfig/displayWidth}} = 0 or {{VideoEncoderConfig/displayHeight}} = 0, return `false`. -4. If {{VideoEncoderConfig/avc}} is present, but {{VideoEncoderConfig/codec}} - does not describe the AVC codec, per [[RFC6381]], return `false`. 4. Return `true`.
@@ -1637,9 +1613,6 @@
-
avc
-
Contains codec specific configuration options for the AVC (H.264) codec.
-
hardwareAcceleration
Configures hardware acceleration for this codec. See @@ -1647,61 +1620,6 @@
-### AvcEncoderConfig ### {#avc-encoder-config} -
-
-dictionary AvcEncoderConfig {
-  AvcBitstreamFormat format = "avc";
-};
-
-
- -
-
format
-
- Configures the format of output AVC {{EncodedVideoChunk}}s. See - {{AvcBitstreamFormat}}. -
-
- -#### AvcBitstreamFormat #### {#avc-bitstream-format} -
-
-enum AvcBitstreamFormat {
-  "annexb",
-  "avc",
-};
-
-
-The {{AvcBitstreamFormat}} determines the location of Sequence Parameter -Set (SPS) and Picture Parameter Set (PPS) data, and mechanisms for -packaging the bitstream. - -
-
annexb
-
- This format is as described by [[!iso14496-10]], Annex B. Notably, - SPS and PPS data are included periodically throughout the - bitstream. - - NOTE: This format is commonly used in live-streaming applications, where - including the SPS and PPS data periodically allows users to easily start - from the middle of the stream. -
-
avc
-
- This format is as described by [[!iso14496-15]], Section 5. Notably, - SPS and PPS data are not included in the bitstream and are - instead passed out of band as a AVCDecoderConfigurationRecord as defined by - [[!iso14496-15]]. This structure is emitted via the - {{VideoEncoder/[[output callback]]}} as the - {{VideoDecoderConfig/description}} of the {{VideoDecoderConfig}} - |output_config|. - - NOTE: This format is commonly used in .MP4 files, where the player generally - has random access to the media data. -
- Hardware Acceleration{#hardware-acceleration} --------------------------------------------- 

From 3fba6841b1296da7ffa8c10d75bc846db4edc9ed Mon Sep 17 00:00:00 2001
From: Chris Cunningham 
Date: Tue, 16 Mar 2021 11:07:26 -0700
Subject: [PATCH 2/3] tidoust feedback: update biblio, spec naming, typos

---
 avc_codec_registration.src.html | 35 +++++++++++++++++++--------------
 codec_registry.src.html         | 24 +++++++++++-----------
 index.src.html                  |  2 +-
 3 files changed, 33 insertions(+), 28 deletions(-)

diff --git a/avc_codec_registration.src.html b/avc_codec_registration.src.html
index bced1c6c..41cc71ef 100644
--- a/avc_codec_registration.src.html
+++ b/avc_codec_registration.src.html
@@ -11,10 +11,10 @@
 Editor: Bernard Aboba, w3cid 65611, Microsoft Corporation https://www.microsoft.com/
 Boilerplate: omit conformance
 
-Abstract: This registration is entered into the [[WebCodecs-Codec-Registry]]. It
-    describes, for AVC (H.264), the (1) fully qualified codec strings, (2) the
-    {{WebCodecs/VideoDecoderConfig.description}} bytes, and (3) the
-    codec-sepcific extensions to the {{WebCodecs/VideoEncoderConfig}}.
+Abstract: This registration is entered into the [[webcodecs-codec-registry]].
+    It describes, for AVC (H.264), the (1) fully qualified codec strings, (2)
+    the {{VideoDecoderConfig.description}} bytes, and (3) the
+    codec-specific extensions to the {{VideoEncoderConfig}}.
 
     The registration is not intended to include any information on whether a
     codec format is encumbered by intellectual property claims. Implementers and
@@ -31,20 +31,25 @@
 
-spec: web-codecs; for: WebCodecs; urlPrefix: https://wicg.github.io/web-codecs/#
+spec: webcodecs; urlPrefix: https://wicg.github.io/web-codecs/#
     type: attribute
         text: VideoDecoderConfig.description; url: dom-videodecoderconfig-description
     type: interface
         text: EncodedVideoChunk; url: encodedvideochunk
         text: VideoEncoder; url: videoencoder
     type: dictionary
-        text: VideoEncoderConfig; url: video-encoder-config
+        text: VideoEncoderConfig; url: dictdef-videoencoderconfig
         text: VideoDecoderConfig; url: dictdef-videodecoderconfig
 
 {
-  "WebCodecs-Codec-Registry": {
+  "webcodecs": {
+      "href": "https://wicg.github.io/web-codecs/",
+      "title": "WebCodecs",
+      "publisher": "WICG"
+  },
+  "webcodecs-codec-registry": {
       "href": "https://wicg.github.io/web-codecs/codec_registry.html",
       "title": "WebCodecs Codec Registry",
       "publisher": "WICG"
@@ -72,17 +77,17 @@
 VideoDecoderConfig description {#videodecoderconfig-description}
 ================================================================
 
-A {{WebCodecs/VideoDecoderConfig.description}} may or may not be required by the
+A {{VideoDecoderConfig.description}} may or may not be required by the
 AVC codec depending on the bitstream format of the AVC content to be decoded.
 
-If the {{WebCodecs/VideoDecoderConfig.description}} includes an
+If the {{VideoDecoderConfig.description}} includes an
 `AVCDecoderConfigurationRecord`, as defined by [[iso14496-15]], section 5.3.3.1,
 it will be assumed that the bitstream is in "avc" format.
 
 NOTE: This format is commonly used in .MP4 files, where the player generally has
     random access to the media data.
 
-If the {{WebCodecs/VideoDecoderConfig.description}} is not provided, it will be
+If the {{VideoDecoderConfig.description}} is not provided, it will be
 assumed that the bitstream is in “annexb” format.
 
 NOTE: "annexb" format is described in greater detail by [[ITU-T-REC-H.264]],
@@ -95,7 +100,7 @@
 
 
 
-/* partial */ dictionary VideoEncoderConfig {
+partial dictionary VideoEncoderConfig {
   AvcEncoderConfig avc;
 };
 
@@ -121,7 +126,7 @@
 

   
format

   

-    Configures the format of output {{WebCodecs/EncodedVideoChunk}}s. See
+    Configures the format of output {{EncodedVideoChunk}}s. See
     {{AvcBitstreamFormat}}.
   

 

@@ -157,9 +162,9 @@
   
avc

   

     SPS and PPS data are not included in the bitstream and are instead emitted
-    via the {{WebCodecs/VideoEncoder}} [[output callback]] as the
-    {{WebCodecs/VideoDecoderConfig.description}} of the
-    {{WebCodecs/VideoDecoderConfig}}.
+    via the {{VideoEncoder}} [[output callback]] as the
+    {{VideoDecoderConfig.description}} of the
+    {{VideoDecoderConfig}}.
     output_config.
 
     NOTE: This format is described in greater detail by [[iso14496-15]],
diff --git a/codec_registry.src.html b/codec_registry.src.html
index 392db7ad..84f1a02b 100644
--- a/codec_registry.src.html
+++ b/codec_registry.src.html
@@ -13,10 +13,10 @@
 Boilerplate: omit conformance
 
 Abstract: This registry is intended to enhance interoperability among
-    implementations and users of [[WebCodecs]]. In particular, this
+    implementations and users of [[webcodecs]]. In particular, this
     registry provides the means to identify and avoid collisions among codec
     strings and provides a mechanism to define codec-specific members of
-    [[WebCodecs]] codec configuration dictionaries.
+    [[webcodecs]] codec configuration dictionaries.
 
     This registry is not intended to include any information on whether a codec
     format is encumbered by intellectual property claims. Implementers and
@@ -34,7 +34,7 @@
 

 
 
-spec: web-codecs; for: WebCodecs; urlPrefix: https://wicg.github.io/web-codecs/#
+spec: web-codecs; urlPrefix: https://wicg.github.io/web-codecs/#
     type: attribute
         text: AudioDecoderConfig.description; url: dom-audiodecoderconfig-description
         text: VideoDecoderConfig.description; url: dom-videodecoderconfig-description
@@ -44,12 +44,12 @@
 
 
 {
-  "WebCodecs": {
+  "webcodecs": {
       "href": "https://wicg.github.io/web-codecs/",
       "title": "WebCodecs",
       "publisher": "WICG"
   },
-  "AVC-REGISTRATION": {
+  "webcodecs-avc-registration": {
       "href": "https://wicg.github.io/web-codecs/avc_codec_registration.html",
       "title": "AVC (H.264) WebCodecs Registration",
       "publisher": "WICG"
@@ -62,9 +62,9 @@
 
 This registry maintains a mapping between codec strings and definitions for (1)
 fully qualified codec string values, (2) codec-specific values for
-{{WebCodecs/VideoDecoderConfig.description}} and
-{{WebCodecs/AudioDecoderConfig.description}}, and (3) codec-specific members of
-the {{WebCodecs/VideoEncoderConfig}} and {{WebCodecs/AudioEncoderConfig}}
+{{VideoDecoderConfig.description}} and
+{{AudioDecoderConfig.description}}, and (3) codec-specific members of
+the {{VideoEncoderConfig}} and {{AudioEncoderConfig}}
 dictionaries.
 
 Registration Entry Requirements {#registration-entry-requirements}
@@ -76,10 +76,10 @@
     a public specification describing how to fully qualify the variable portion
     of the string.
 3. If the described codec requires that codec-specific bytes be provided as part
-    of the {{WebCodecs/VideoDecoderConfig.description}} or the
-    {{WebCodecs/AudioDecoderConfig.description}}, the registration must link to
+    of the {{VideoDecoderConfig.description}} or the
+    {{AudioDecoderConfig.description}}, the registration must link to
     a public specification describing how to populate these fields.
-4. If the {{WebCodecs/AudioEncoderConfig}} or {{WebCodecs/VideoEncoderConfig}}
+4. If the {{AudioEncoderConfig}} or {{VideoEncoderConfig}}
     dictionaries are extended with members specific to the described codec, the
     registration must link to a public specification describing how to populate
     these fields.
@@ -157,7 +157,7 @@
   
     avc1.*
     AVC / H.264
-    [AVC (H.264) WebCodecs Registration](avc_codec_registration.html) [[AVC-REGISTRATION]]
+    [AVC (H.264) WebCodecs Registration](avc_codec_registration.html) [[webcodecs-avc-registration]]
   
   
     vp8
diff --git a/index.src.html b/index.src.html
index e9c50fc7..24c0ec9d 100644
--- a/index.src.html
+++ b/index.src.html
@@ -3,7 +3,7 @@
 Repository: wicg/web-codecs
 Status: CG-DRAFT
 ED: https://wicg.github.io/web-codecs/
-Shortname: web-codecs
+Shortname: webcodecs
 Level: 1
 Group: wicg
 Editor: Chris Cunningham, w3cid 114832, Google Inc. https://google.com/

From 49baae72c9c6d0c840467bd5070ab2c1737be8f9 Mon Sep 17 00:00:00 2001
From: Chris Cunningham 
Date: Wed, 17 Mar 2021 16:38:51 -0700
Subject: [PATCH 3/3] Use UPPER CASE for WC biblio refs

---
 avc_codec_registration.src.html | 14 +++++++-------
 codec_registry.src.html         |  8 ++++----
 index.src.html                  | 14 +++++++-------
 3 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/avc_codec_registration.src.html b/avc_codec_registration.src.html
index 41cc71ef..38fe3da8 100644
--- a/avc_codec_registration.src.html
+++ b/avc_codec_registration.src.html
@@ -2,7 +2,7 @@
 Title: AVC (H.264) WebCodecs Registration
 Repository: wicg/web-codecs
 Status: CG-DRAFT
-Shortname: web-codecs-avc-codec-registration
+Shortname: webcodecs-avc-codec-registration
 Level: none
 Group: wicg
 ED: none
@@ -44,12 +44,12 @@
 
 
 {
-  "webcodecs": {
+  "WEBCODECS": {
       "href": "https://wicg.github.io/web-codecs/",
       "title": "WebCodecs",
       "publisher": "WICG"
   },
-  "webcodecs-codec-registry": {
+  "WEBCODECS-CODEC-REGISTRY": {
       "href": "https://wicg.github.io/web-codecs/codec_registry.html",
       "title": "WebCodecs Codec Registry",
       "publisher": "WICG"
@@ -81,11 +81,11 @@
 AVC codec depending on the bitstream format of the AVC content to be decoded.
 
 If the {{VideoDecoderConfig.description}} includes an
-`AVCDecoderConfigurationRecord`, as defined by [[iso14496-15]], section 5.3.3.1,
-it will be assumed that the bitstream is in "avc" format.
+`AVCDecoderConfigurationRecord`, as defined by [[iso14496-15]], section
+5.3.3.1, it will be assumed that the bitstream is in "avc" format.
 
-NOTE: This format is commonly used in .MP4 files, where the player generally has
-    random access to the media data.
+NOTE: This format is commonly used in .MP4 files, where the player generally
+    has random access to the media data.
 
 If the {{VideoDecoderConfig.description}} is not provided, it will be
 assumed that the bitstream is in “annexb” format.
diff --git a/codec_registry.src.html b/codec_registry.src.html
index 84f1a02b..e28f69c2 100644
--- a/codec_registry.src.html
+++ b/codec_registry.src.html
@@ -2,7 +2,7 @@
 Title: WebCodecs Codec Registry
 Repository: wicg/web-codecs
 Status: CG-DRAFT
-Shortname: web-codecs-codec-registry
+Shortname: webcodecs-codec-registry
 Level: none
 Group: wicg
 ED: none
@@ -44,12 +44,12 @@
 
 
 {
-  "webcodecs": {
+  "WEBCODECS": {
       "href": "https://wicg.github.io/web-codecs/",
       "title": "WebCodecs",
       "publisher": "WICG"
   },
-  "webcodecs-avc-registration": {
+  "WEBCODECS-AVC-REGISTRATION": {
       "href": "https://wicg.github.io/web-codecs/avc_codec_registration.html",
       "title": "AVC (H.264) WebCodecs Registration",
       "publisher": "WICG"
@@ -157,7 +157,7 @@
   
     avc1.*
     AVC / H.264
-    [AVC (H.264) WebCodecs Registration](avc_codec_registration.html) [[webcodecs-avc-registration]]
+    [AVC (H.264) WebCodecs Registration](avc_codec_registration.html) [[WEBCODECS-AVC-REGISTRATION]]
   
   
     vp8
diff --git a/index.src.html b/index.src.html
index 24c0ec9d..88708dea 100644
--- a/index.src.html
+++ b/index.src.html
@@ -72,7 +72,7 @@
 
 
 {
-  "CODEC-REGISTRY": {
+  "WEBCODECS-CODEC-REGISTRY": {
       "href": "https://wicg.github.io/web-codecs/codec_registry.html",
       "title": "WebCodecs Codec Registry",
       "publisher": "WICG"
@@ -1140,7 +1140,7 @@
                     {{VideoDecoderConfig/description}} to describe codec
                     specific "extradata", the use of which may be further
                     described in codec registrations listed in the
-                    [[CODEC-REGISTRY]].
+                    [[WEBCODECS-CODEC-REGISTRY]].
         3. If |output_config| and {{VideoEncoder/[[active output config]]}} are
             equal dictionaries, set |output_config| to null. Otherwise,
             set {{VideoEncoder/[[active output config]]}} to |output_config|.
@@ -1342,7 +1342,7 @@
     hence, only the value of the codecs parameter is accepted.
 
 The format and semantics for codec strings are defined by codec registrations
-listed in the [[CODEC-REGISTRY]]. A compliant implementation may support any
+listed in the [[WEBCODECS-CODEC-REGISTRY]]. A compliant implementation may support any
 combination of codec registrations or none at all.
 
 AudioDecoderConfig{#audio-decoder-config}
@@ -1377,7 +1377,7 @@
   

     A sequence of codec specific bytes, commonly known as extradata.
 
-    NOTE: The registrations in the [[CODEC-REGISTRY]] describe whether/how to
+    NOTE: The registrations in the [[WEBCODECS-CODEC-REGISTRY]] describe whether/how to
         populate this sequence, corresponding to the provided
         {{AudioDecoderConfig/codec}}.
   

@@ -1428,7 +1428,7 @@
   

     A sequence of codec specific bytes, commonly known as extradata.
 
-    NOTE: The registrations in the [[CODEC-REGISTRY]] may describe whether/how
+    NOTE: The registrations in the [[WEBCODECS-CODEC-REGISTRY]] may describe whether/how
         to populate this sequence, corresponding to the provided
         {{VideoDecoderConfig/codec}}.
   

@@ -1502,7 +1502,7 @@
 

 
 NOTE: Codec-specific extensions to {{AudioEncoderConfig}} may be defined by the
-    registrations in the [[CODEC-REGISTRY]].
+    registrations in the [[WEBCODECS-CODEC-REGISTRY]].
 
 To check if an {{AudioEncoderConfig}} is a valid AudioEncoderConfig,
 run these steps:
@@ -1539,7 +1539,7 @@
 

 
 NOTE: Codec-specific extensions to {{VideoEncoderConfig}} may be defined by the
-    registrations in the [[CODEC-REGISTRY]].
+    registrations in the [[WEBCODECS-CODEC-REGISTRY]].
 
 To check if a {{VideoEncoderConfig}} is a valid VideoEncoderConfig,
     run these steps: