Drop local custom definitions where possible

Bikeshed now contains cross-reference anchors from Webref, which means it now
knows about a number of "new" specifications, including WebCodecs, Media Capture
specs, the Infra standard, etc. See announcement at:
https://lists.w3.org/Archives/Public/spec-prod/2023JanMar/0004.html

In turn, this means that WebCodecs specs no longer need to list and maintain a
local database of cross-references, except in rare cases (such as when a term
is not exported by the referenced spec).

This update drops local definitions where ever possible, adjusting references
in the prose as needed. A few definitions remain here and there to list external
terms that are not exported, along with a couple of linking defaults in the
WebCodecs spec.

One temporary hiccup: the markup definitions of `CanvasImageSource` and
`drawImage()` are slightly incorrect. Hence the need to re-define them locally.
To be removed once the HTML spec is fixed.

In codec registration specs, note that the form
`{{VideoDecoderConfig/description|VideoDecoderConfig.description}}` is used to
output `VideoDecoderConfig.description` (with the right link to the WebCodecs
spec) when merely having `description` would be ambiguous.

Author: tidoust

aac_codec_registration.src.html

@@ -13,10 +13,10 @@
 
 Abstract: This registration is entered into the [[webcodecs-codec-registry]].
     It describes, for AAC, the (1) fully qualified codec strings, (2) the
-    codec-specific {{EncodedAudioChunk}} [=EncodedAudioChunk/[[internal data]]=]
-    bytes, (3) the {{AudioDecoderConfig.description}} bytes, (4) the values of
-    {{EncodedAudioChunk}} [=EncodedAudioChunk/[[type]]=], and (5) the
-    codec-specific extensions to {{AudioEncoderConfig}}
+    codec-specific {{EncodedAudioChunk}} {{EncodedAudioChunk/[[internal data]]}}
+    bytes, (3) the {{AudioDecoderConfig/description|AudioDecoderConfig.description}}
+    bytes, (4) the values of {{EncodedAudioChunk}} {{EncodedAudioChunk/[[type]]}},
+    and (5) the codec-specific extensions to {{AudioEncoderConfig}}
 
     The registration is not intended to include any information on whether a
     codec format is encumbered by intellectual property claims. Implementers and
@@ -32,23 +32,6 @@
 !Version History: <a href="https://github.com/w3c/webcodecs/commits">https://github.com/w3c/webcodecs/commits</a>
 </pre>
 
-<pre class='anchors'>
-spec: WEBCODECS; urlPrefix: https://w3c.github.io/webcodecs/#
-    type: attribute
-        text: AudioDecoderConfig.description; url: dom-audiodecoderconfig-description
-        text: AudioDecoderConfig.sampleRate; url: dom-audiodecoderconfig-samplerate
-        text: AudioDecoderConfig.numberOfChannels; url: dom-audiodecoderconfig-numberofchannels
-    type: dfn
-        for: EncodedAudioChunkType; text: key; url: dom-encodedaudiochunktype-key
-        for: EncodedAudioChunk; text: [[internal data]]; url: dom-encodedaudiochunk-internal-data-slot
-        for: EncodedAudioChunk; text: [[type]]; url: dom-encodedaudiochunk-type-slot
-    type: interface
-        text: EncodedAudioChunk; url: encodedaudiochunk
-    type: dictionary
-        text: AudioDecoderConfig; url: dictdef-audiodecoderconfig
-        text: AudioEncoderConfig; url: dictdef-audioencoderconfig
-</pre>
-
 <pre class='biblio'>
 {
   "iso14496-3": {
@@ -76,32 +59,32 @@
 ================================================
 
 If the bitstream is in {{AacBitstreamFormat/adts}} format, the
-[=EncodedAudioChunk/[[internal data]]=] of {{EncodedAudioChunk}}s are expected
+{{EncodedAudioChunk/[[internal data]]}} of {{EncodedAudioChunk}}s are expected
 to be an ADTS frame, as described in section 1.A.3.2 of [[iso14496-3]].
 
 If the bitstream is in {{AacBitstreamFormat/aac}} format, the
-[=EncodedAudioChunk/[[internal data]]=] of {{EncodedAudioChunk}}s are expected
+{{EncodedAudioChunk/[[internal data]]}} of {{EncodedAudioChunk}}s are expected
 to be a raw AAC frame (syntax element `raw_data_block()`), as described in
 section 4.4.2.1 of [[iso14496-3]].
 
 AudioDecoderConfig description {#audiodecoderconfig-description}
 ================================================================
 
-If {{AudioDecoderConfig.description}} is present, it is assumed to a
+If {{AudioDecoderConfig/description}} is present, it is assumed to a
 `AudioSpecificConfig` as defined in [[iso14496-3]] section 1.6.2.1, Table 1.15,
 and the bitstream is assumed to be in {{AacBitstreamFormat/aac}}.
 
-If the {{AudioDecoderConfig.description}} is not present, the bitstream is
+If the {{AudioDecoderConfig/description}} is not present, the bitstream is
 assumed to be in {{AacBitstreamFormat/adts}} format.
 
-The {{AudioDecoderConfig.sampleRate}} and {{AudioDecoderConfig.numberOfChannels}}
+The {{AudioDecoderConfig/sampleRate}} and {{AudioDecoderConfig/numberOfChannels}}
 members are ignored.
 
 EncodedAudioChunk type {#encodedaudiochunk-type}
 ================================================
 
-The [=EncodedAudioChunk/[[type]]=] for an {{EncodedAudioChunk}} containing
-AAC is always "[=EncodedAudioChunkType/key=]".
+The {{EncodedAudioChunk/[[type]]}} for an {{EncodedAudioChunk}} containing
+AAC is always "{{EncodedAudioChunkType/key}}".
 
 NOTE: Once the initialization has succeeded, any AAC packet can be decoded at
     any time without error, but this might not result in the expected audio
@@ -161,12 +144,12 @@
       <dt><dfn enum-value for=AacBitstreamFormat>aac</dfn></dt>
       <dd>
         The metadata of the encoded audio stream are provided at configuration via
-        {{AudioDecoderConfig.description}}.
+        {{AudioDecoderConfig/description|AudioDecoderConfig.description}}.
       </dd>
       <dt><dfn enum-value for=AacBitstreamFormat>adts</dfn></dt>
       <dd>
         The metadata of the encoded audio stream are provided in each ADTS frame,
-        and therefore no {{AudioDecoderConfig.description}} is necessary.
+        and therefore no {{AudioDecoderConfig/description|AudioDecoderConfig.description}} is necessary.
     </dl>
 
 Privacy Considerations {#privacy-considerations}

alaw_codec_registration.src.html

@@ -14,9 +14,9 @@
 Abstract: This registration is entered into the [[webcodecs-codec-registry]].
     It describes, for A-law encoded PCM, the (1) fully qualified codec strings,
     (2) the codec-specific {{EncodedAudioChunk}}
-    [=EncodedAudioChunk/[[internal data]]=] bytes, (3) the
-    {{AudioDecoderConfig.description}}, and (4) the values of
-    {{EncodedAudioChunk}} [=EncodedAudioChunk/[[type]]=].
+    {{EncodedAudioChunk/[[internal data]]}} bytes, (3) the
+    {{AudioDecoderConfig/description|AudioDecoderConfig.description}},
+    and (4) the values of {{EncodedAudioChunk}} {{EncodedAudioChunk/[[type]]}}.
 
     The registration is not intended to include any information on whether a
     codec format is encumbered by intellectual property claims. Implementers and
@@ -32,21 +32,6 @@
 !Version History: <a href="https://github.com/w3c/webcodecs/commits">https://github.com/w3c/webcodecs/commits</a>
 </pre>
 
-<pre class='anchors'>
-spec: WEBCODECS; urlPrefix: https://w3c.github.io/webcodecs/#
-    type: attribute
-        text: AudioDecoderConfig.description; url: dom-audiodecoderconfig-description
-    type: dfn
-        for: EncodedAudioChunkType; text: key; url: dom-encodedaudiochunktype-key
-        for: EncodedAudioChunk; text: [[internal data]]; url: dom-encodedaudiochunk-internal-data-slot
-        for: EncodedAudioChunk; text: [[type]]; url: dom-encodedaudiochunk-type-slot
-    type: interface
-        text: EncodedAudioChunk; url: encodedaudiochunk
-    type: dictionary
-        text: AudioDecoderConfig; url: dictdef-audiodecoderconfig
-        text: AudioEncoderConfig; url: dictdef-audioencoderconfig
-</pre>
-
 <pre class='biblio'>
 {
   "ITU-G.711": {
@@ -66,21 +51,21 @@
 EncodedAudioChunk data {#encodedaudiochunk-data}
 ================================================
 
-{{EncodedAudioChunk}} [=EncodedAudioChunk/[[internal data]]=] is expected to be
+{{EncodedAudioChunk}} {{EncodedAudioChunk/[[internal data]]}} is expected to be
 a sequence of bytes of arbitrary length, where each byte is an A-law
 encoded PCM sample as defined by Tables 1a and 1b in [[ITU-G.711]].
 
 AudioDecoderConfig description {#audiodecoderconfig-description}
 ================================================================
 
-An {{AudioDecoderConfig.description}} is expected to be omitted from the
+The {{AudioDecoderConfig/description}} is expected to be omitted from the
 {{AudioDecoderConfig}}.
 
 EncodedAudioChunk type {#encodedaudiochunk-type}
 ================================================
 
-The [=EncodedAudioChunk/[[type]]=] for an {{EncodedAudioChunk}} containing
-A-law PCM is always "[=EncodedAudioChunkType/key=]".
+The {{EncodedAudioChunk/[[type]]}} for an {{EncodedAudioChunk}} containing
+A-law PCM is always "{{EncodedAudioChunkType/key}}".
 
 Privacy Considerations {#privacy-considerations}
 ==========================================================================

av1_codec_registration.src.html

@@ -14,9 +14,9 @@
 Abstract: This registration is entered into the [[webcodecs-codec-registry]].
     It describes, for AV1, the (1) fully qualified codec strings,
     (2) the codec-specific {{EncodedVideoChunk}}
-    [=EncodedVideoChunk/[[internal data]]=] bytes, (3) the
-    {{VideoDecoderConfig.description}} bytes, and (4) the values of
-    {{EncodedVideoChunk}} [=EncodedVideoChunk/[[type]]=].
+    {{EncodedVideoChunk/[[internal data]]}} bytes, (3) the
+    {{VideoDecoderConfig/description|VideoDecoderConfig.description}} bytes, and
+    (4) the values of {{EncodedVideoChunk}} {{EncodedVideoChunk/[[type]]}}.
 
     The registration is not intended to include any information on whether a
     codec format is encumbered by intellectual property claims. Implementers and
@@ -32,24 +32,6 @@
 !Version History: <a href="https://github.com/w3c/webcodecs/commits">https://github.com/w3c/webcodecs/commits</a>
 </pre>
 
-<pre class='anchors'>
-spec: WEBCODECS; urlPrefix: https://w3c.github.io/webcodecs/#
-    type: attribute
-        text: EncodedVideoChunkMetadata.decoderConfig; url: dom-encodedvideochunkmetadata-decoderconfig
-        for: EncodedVideoChunkType; text: key; url: dom-encodedvideochunktype-key
-        text: VideoDecoderConfig.description; url: dom-videodecoderconfig-description
-    type: dfn
-        for: EncodedVideoChunk; text: [[internal data]]; url: dom-encodedvideochunk-internal-data-slot
-        for: EncodedVideoChunk; text: [[type]]; url: dom-encodedvideochunk-type-slot
-        for: VideoEncoder; text: [[output callback]]; url: dom-videoencoder-output-callback-slot
-    type: interface
-        text: EncodedVideoChunk; url: encodedvideochunk
-        text: VideoEncoder; url: videoencoder
-    type: dictionary
-        text: VideoEncoderConfig; url: dictdef-videoencoderconfig
-        text: VideoDecoderConfig; url: dictdef-videodecoderconfig
-</pre>
-
 <pre class='biblio'>
 {
   "AV1": {
@@ -74,19 +56,19 @@
 EncodedVideoChunk data {#encodedvideochunk-data}
 ================================================
 
-{{EncodedVideoChunk}} [=EncodedVideoChunk/[[internal data]]=] is expected to be
+{{EncodedVideoChunk}} {{EncodedVideoChunk/[[internal data]]}} is expected to be
 data compliant to the "low-overhead bitstream format" as described in Section 5
 of [[AV1]].
 
 VideoDecoderConfig description {#videodecoderconfig-description}
 ================================================================
 
-{{VideoDecoderConfig.description}} is not used for this codec.
+{{VideoDecoderConfig/description}} is not used for this codec.
 
 EncodedVideoChunk type {#encodedvideochunk-type}
 ================================================
 
-If an {{EncodedVideoChunk}}'s [=EncodedVideoChunk/[[type]]=] is
+If an {{EncodedVideoChunk}}'s {{EncodedVideoChunk/[[type]]}} is
 {{EncodedVideoChunkType/key}}, then the {{EncodedVideoChunk}} is expected to
 contain a frame with a `frame_type` of `KEY_FRAME` as defined in Section
 6.8.2 of [[AV1]].

avc_codec_registration.src.html

@@ -14,10 +14,10 @@
 Abstract: This registration is entered into the [[webcodecs-codec-registry]].
     It describes, for AVC (H.264), the (1) fully qualified codec strings,
     (2) the codec-specific {{EncodedVideoChunk}}
-    [=EncodedVideoChunk/[[internal data]]=] bytes, (3) the
-    {{VideoDecoderConfig.description}} bytes, (4) the values of
-    {{EncodedVideoChunk}} [=EncodedVideoChunk/[[type]]=], and (5) the
-    codec-specific extensions to {{VideoEncoderConfig}}
+    {{EncodedVideoChunk/[[internal data]]}} bytes, (3) the
+    {{VideoDecoderConfig/description|VideoDecoderConfig.description}} bytes,
+    (4) the values of {{EncodedVideoChunk}} {{EncodedVideoChunk/[[type]]}},
+    and (5) the codec-specific extensions to {{VideoEncoderConfig}}
 
     The registration is not intended to include any information on whether a
     codec format is encumbered by intellectual property claims. Implementers and
@@ -33,24 +33,6 @@
 !Version History: <a href="https://github.com/w3c/webcodecs/commits">https://github.com/w3c/webcodecs/commits</a>
 </pre>
 
-<pre class='anchors'>
-spec: WEBCODECS; urlPrefix: https://w3c.github.io/webcodecs/#
-    type: attribute
-        text: EncodedVideoChunkMetadata.decoderConfig; url: dom-encodedvideochunkmetadata-decoderconfig
-        for: EncodedVideoChunkType; text: key; url: dom-encodedvideochunktype-key
-        text: VideoDecoderConfig.description; url: dom-videodecoderconfig-description
-    type: dfn
-        for: EncodedVideoChunk; text: [[internal data]]; url: dom-encodedvideochunk-internal-data-slot
-        for: EncodedVideoChunk; text: [[type]]; url: dom-encodedvideochunk-type-slot
-        for: VideoEncoder; text: [[output callback]]; url: dom-videoencoder-output-callback-slot
-    type: interface
-        text: EncodedVideoChunk; url: encodedvideochunk
-        text: VideoEncoder; url: videoencoder
-    type: dictionary
-        text: VideoEncoderConfig; url: dictdef-videoencoderconfig
-        text: VideoDecoderConfig; url: dictdef-videodecoderconfig
-</pre>
-
 <pre class='biblio'>
 {
   "ITU-T-REC-H.264": {
@@ -78,34 +60,34 @@
 EncodedVideoChunk data {#encodedvideochunk-data}
 ================================================
 
-{{EncodedVideoChunk}} [=EncodedVideoChunk/[[internal data]]=] is expected to be
+{{EncodedVideoChunk}} {{EncodedVideoChunk/[[internal data]]}} is expected to be
 an access unit as defined in [[ITU-T-REC-H.264]] section 7.4.1.2.
 
 NOTE: An access unit contains exactly one primary coded picture.
 
 If the bitstream is in {{AvcBitstreamFormat/avc}} format,
-[=EncodedVideoChunk/[[internal data]]=] is assumed to be in canonical format, as
+{{EncodedVideoChunk/[[internal data]]}} is assumed to be in canonical format, as
 defined in [[iso14496-15]] section 5.3.2.
 
 If the bitstream is in {{AvcBitstreamFormat/annexb}} format,
-[=EncodedVideoChunk/[[internal data]]=] is assumed to be in in Annex B format,
+{{EncodedVideoChunk/[[internal data]]}} is assumed to be in in Annex B format,
 as defined in [[ITU-T-REC-H.264]] Annex B.
 
-NOTE: Since [=EncodedVideoChunk/[[internal data]]=] is inherently byte-aligned,
+NOTE: Since {{EncodedVideoChunk/[[internal data]]}} is inherently byte-aligned,
     implementations are not required to recover byte-alignment.
 
 VideoDecoderConfig description {#videodecoderconfig-description}
 ================================================================
 
-If the {{VideoDecoderConfig.description}} is present, it is assumed to be an
+If the {{VideoDecoderConfig/description}} is present, it is assumed to be an
 `AVCDecoderConfigurationRecord`, as defined by [[iso14496-15]], section
 5.3.3.1, and the bitstream is assumed to be in {{AvcBitstreamFormat/avc}}
 format.
 
 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 present, the bitstream is
+If the {{VideoDecoderConfig/description}} is not present, the bitstream is
 assumed to be in {{AvcBitstreamFormat/annexb}} format.
 
 NOTE: "annexb" format is described in greater detail by [[ITU-T-REC-H.264]],
@@ -116,16 +98,17 @@
 EncodedVideoChunk type {#encodedvideochunk-type}
 ================================================
 
-If an {{EncodedVideoChunk}}'s [=EncodedVideoChunk/[[type]]=] is
+If an {{EncodedVideoChunk}}'s {{EncodedVideoChunk/[[type]]}} is
 {{EncodedVideoChunkType/key}}, and the bitstream is in
 {{AvcBitstreamFormat/avc}} format, then the {{EncodedVideoChunk}} is expected to
 contain a primary coded picture that is an instantaneous decoding refresh (IDR)
 picture.
 
 NOTE: If the bitstream is in {{AvcBitstreamFormat/avc}} format, parameter sets
-    necessary for decoding are included in {{VideoDecoderConfig.description}}.
+    necessary for decoding are included in
+    {{VideoDecoderConfig/description|VideoDecoderConfig.description}}.
 
-If an {{EncodedVideoChunk}}'s [=EncodedVideoChunk/[[type]]=] is
+If an {{EncodedVideoChunk}}'s {{EncodedVideoChunk/[[type]]}} is
 {{EncodedVideoChunkType/key}}, and the bitstream is in
 {{AvcBitstreamFormat/annexb}} format, then the {{EncodedVideoChunk}} is expected
 to contain both a primary coded picture that is an instantaneous decoding
@@ -195,9 +178,9 @@
   <dt><dfn enum-value for=AvcBitstreamFormat>avc</dfn></dt>
   <dd>
     SPS and PPS data are not included in the bitstream and are instead emitted
-    via the [=VideoEncoder/[[output callback]]=] as the
-    {{VideoDecoderConfig.description}} of the
-    {{EncodedVideoChunkMetadata.decoderConfig}}.
+    via the {{VideoEncoder/[[output callback]]}} as the
+    {{VideoDecoderConfig/description|VideoDecoderConfig.description}} of the
+    {{EncodedVideoChunkMetadata/decoderConfig|EncodedVideoChunkMetadata.decoderConfig}}.
 
     NOTE: This format is described in greater detail by [[iso14496-15]],
         section 5.3. This format is commonly used in .MP4 files, where the

codec_registry.src.html

@@ -34,23 +34,6 @@
 !Version History: <a href="https://github.com/w3c/webcodecs/commits">https://github.com/w3c/webcodecs/commits</a>
 </pre>
 
-<pre class='anchors'>
-spec: WEBCODECS; urlPrefix: https://w3c.github.io/webcodecs/#
-    type: attribute
-        text: AudioDecoderConfig.description; url: dom-audiodecoderconfig-description
-        text: VideoDecoderConfig.description; url: dom-videodecoderconfig-description
-    type: dfn
-        for: EncodedVideoChunk; text: [[type]]; url: dom-encodedaudiochunk-type-slot
-    type: interface
-        text: EncodedAudioChunk; url: encodedaudiochunk
-        text: EncodedVideoChunk; url: encodedvideochunk
-    type: dictionary
-        text: AudioDecoderConfig; url: dictdef-audiodecoderconfig
-        text: AudioEncoderConfig; url: dictdef-audioencoderconfig
-        text: VideoDecoderConfig; url: dictdef-videodecoderconfig
-        text: VideoEncoderConfig; url: dictdef-videoencoderconfig
-</pre>
-
 
 Organization {#organization}
 ============================
@@ -78,7 +61,7 @@
     2. {{EncodedAudioChunk}} or {{EncodedVideoChunk}} internal data
     3. {{AudioDecoderConfig}} or {{VideoDecoderConfig}} description bytes
     4. Expectations for {{EncodedAudioChunk}} or {{EncodedVideoChunk}}
-        [=EncodedVideoChunk/[[type]]=]
+        {{EncodedVideoChunk/[[type]]}}
 3. Where applicable, a registration specification may include a section
     describing extensions to {{VideoEncoderConfig}} or {{AudioEncoderConfig}}
     dictionaries.