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Explainer None Specification https://w3c.github.io/webcodecs/#dom-audioencoderconfig-bitratemode Summary Some audio codecs support specifying the audio encoder bitrate modes. This feature adds a "bitrateMode" flag with a default value of “variable” to WebCodec's AudioEncoderConfig, which mirrors the functionality already present for VideoEncoderConfig <https://w3c.github.io/webcodecs/#dom-videoencoderconfig-bitratemode>. This flag will allow web authors to choose between encoding audio with a variable bitrate or a constant bitrate. Specific codec encoder implementations might have slightly different terminology (e.g. `CBR` vs `VBR` for Opus), but all of them should map to the general concept of "constant" versus "variable" bitrate. The two options have the following effects: - “variable”: allows an audio encoder to increase or lower its bitrate according to the content of the audio it is encoding, in order to preserve bandwidth/binary-size, while still maintaining a target quality. For example, an encoder might lower its bitrate when encoding silence, and revert to a full bitrate when encoding speech. - “constant” : forces an audio encoder to maintain the same bitrate, regardless of the audio content. This can be useful when a predictable bandwidth consumption is preferable. As of M118, this flag will affect two codecs on Chromium: Opus and AAC. Blink component Blink>Media>WebCodecs <https://bugs.chromium.org/p/chromium/issues/list?q=component:Blink%3EMedia%3EWebCodecs> TAG review None TAG review status Not applicable Risks Interoperability and Compatibility The risk is low. Firefox has not yet shipped WebCodecs, but is currently developing it. Safari has developed video WebCodecs, but not yet audio. The flag should be easy for other browsers to add as they implement WebCodecs. Gecko: Positive (https://github.com/mozilla/standards-positions/issues/837) WebKit: No signal (https://github.com/WebKit/standards-positions/issues/218) Web developers: Positive, as feature was originally a developper request – https://github.com/w3c/webcodecs/issues/649 Other signals: WebView application risks This change does not deprecate existing APIs, and only supplements existing APIs, with a sensible default. This should not be a WebView risk. Debuggability Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)? Yes Is this feature fully tested by web-platform-tests <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md> ? It will be at the time it is implemented. Example test <https://chromium-review.googlesource.com/c/chromium/src/+/4654994/1/third_party/blink/web_tests/external/wpt/webcodecs/audio-encoder-codec-specific.https.any.js> . Flag name on chrome://flags N/A Finch feature name N/A Non-finch justification Simple parameter change Requires code in //chrome? False Tracking bug https://bugs.chromium.org/p/chromium/issues/detail?id=1462467 Estimated milestones Shipping on desktop 118 Shipping on Android 118 Anticipated spec changes None Link to entry on the Chrome Platform Status https://chromestatus.com/feature/5084320053592064 -- You received this message because you are subscribed to the Google Groups "blink-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to blink-dev+unsubscr...@chromium.org. To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CABrVPoak2%3DgxnREAhxe83D-BpSD0xF%3DnRFDbSiS8qrF0ZBQB7A%40mail.gmail.com.
