1915002 - Check AudioDecoderConfig's description for some codecs

Status: RESOLVED FIXED

(Core :: Audio/Video: Web Codecs, defect, P1)

Description

[C.M.Chang[:chunmin]]

By https://w3c.github.io/webcodecs/codec_registry.html#audio-codec-registry, we should check if description is present in AudioDecoderConfig for some codecs like vorbis and flac. The below is a summary chart.

codec name	codec string	description	public specification
Flac	flac	required	https://www.w3.org/TR/webcodecs-flac-codec-registration/
MP3	mp3	not used	https://www.w3.org/TR/webcodecs-mp3-codec-registration/
AAC	mp4a.*	bitstream is assumed to be aac if description is present. Otherwise, adts	https://www.w3.org/TR/webcodecs-aac-codec-registration/
Opus	opus	bitstream is assumed to be ogg if description is present. Otherwise, opus	https://www.w3.org/TR/webcodecs-opus-codec-registration/
Vorbis	vorbis	required	https://www.w3.org/TR/webcodecs-vorbis-codec-registration/
u-law PCM	ulaw	omitted	https://www.w3.org/TR/webcodecs-ulaw-codec-registration/
A-law PCM	alaw	omitted	https://www.w3.org/TR/webcodecs-alaw-codec-registration/
Linear PCM	pcm-*	omitted	https://www.w3.org/TR/webcodecs-pcm-codec-registration/

Comment 1

[C.M.Chang[:chunmin]]

Attachment: Bug 1915002 - Check AudioDecoderConfig description for FLAC and Vorbis

By FLAC and Vorbis specs for WebCodecs [1, 2], the description data in
their AudioDecoderConfigs are required. Previously, no check for
description data is in WebCodecs code. This patch ensures that the
description is present for the FLAV and Vorbis codecs.

[1] https://www.w3.org/TR/webcodecs-flac-codec-registration/
[2] https://www.w3.org/TR/webcodecs-vorbis-codec-registration/

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/6ff3f1fba36f
Check AudioDecoderConfig description for FLAC and Vorbis r=media-playback-reviewers,alwu

Comment 3

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/47817 for changes under testing/web-platform/tests

Comment 4

[Iulian Moraru]

https://hg.mozilla.org/mozilla-central/rev/6ff3f1fba36f

Comment 5

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR merged by moz-wptsync-bot

Comment 6

[Paul Adenot (:padenot)]

This is unfortunately incorrect, it means that:

AudioDecoder.isConfigSupport({codec: "flac", numberOfChannels: 1, sampleRate: 48000});

resolves to a promise that says that it isn't supported (and it should say yes). Unfortunately, audioDecoder-codec-specific.https.any.js lacked tests for those two codecs, and the tests added are incorrect. The spec for this is: https://w3c.github.io/webcodecs/#check-configuration-support, and the check is intentionally not very thorough: this method is meant to know if this implementation generally supports a codec, not to check if configure(...) will success with very specific parameters. In general, isConfigSupported is done ahead of downloading any media content, so we don't have a description here.