Support Ogg Opus in webm container format

Number:rdar://9106394 Date Originated:5/14/2021
Status:Open Resolved:
Product:macOS Product Version:
Classification: Reproducible:
WebM is an audiovisual media file format. It is primarily intended to offer a royalty-free alternative to use in the HTML5 video and the HTML5 audio elements. The development of the format is sponsored by Google, and the corresponding software is distributed under a BSD license. Native WebM is supported by many of the major browsers. 

WebM can be a container for Ogg Opus. Currently, the only way to play Ogg Opus on Mac or iOS is using CAF (Core Audio Format) files, which is used exclusively on Apple platforms.  To make applications or websites that utilize Ogg Opus audio, the files have to be doubly encoded in WebM and CAF even though the contain the exact same data.

Please support WebM on Apple platforms, both in the system APIs and Safari.


There's also a tangential issue where there is no support for VBR Opus whatsoever -- people tend to make them because opusenc makes them by default. As a result, you can't just remux to caf, but you need to also do an actual re-encode in CBR. (FFmpeg will gladly make a CAF with VBR Opus. It just won't play.)

By arthur200126 at Feb. 14, 2024, 1:48 p.m. (reply...)

iOS 15 supports WebM, but it looks like only for video

I saw that Safari in iOS 15 has added support for WebM Web Audio as an Experimental WebKit Feature (on by default).

However, it doesn't work with Ogg Opus in WebM container. Here is an example:

Direct link to audio:

This works on Chrome, Firefox and Microsoft Edge but not on Safari (neither Safari 15 on macOS Big Sur or Safari on iOS 15).

In WWWDC2021 presentation "Develop advanced web content", there is a discussion of WebM but it seems to be centered around video container with VP8/VP9 with Ogg Vorbis audio:

By chris_hubbard at Oct. 7, 2021, 1:01 p.m. (reply...)

There is no way to playback opus encodec audio in Safari, without transcoding (demux webm, mux to caf). This is possible in ffmpeg, however that will involve extra backend and server costs (and energy).

Please support opus in the webm container format too.

By kasperkamperman at May 15, 2021, 6:33 p.m. (reply...)

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