Improve spatial audio capabilities (high channel count, surround, etc.)

[padenot]

For now, the support is fairly minimal and a bit inconsistent.

[aboba]

Today, immersive/spatial capabilities are typically provided via WebAudio and container standards, such as:

• RFC 8486
• IAMF

So I'm curious what you think needs to be added in WebCodecs.

[padenot]

Those two came to mind yes, but I was also thinking of making it clear how layouts are supported, in relation to how the Web Audio API does things, and how to handle (e.g.) Opus mapping family 255.

[juanBerger]

Opus mapping family 255.

Are you referring to this?
https://opus-codec.org/docs/opus_api-1.5/group__opus__multistream.html#details

If so I assume that means decoding multistream packets is not supported? Thanks

[tguilbert-google]

If so I assume that means decoding multistream packets is not supported?

Decoding multi-stream packets is supported, as long as the appropriate description field is set.

I think that this issue is partially about mapping the channels once they are decoded? For example, channel mapping 1 (which is multistream) has standard layouts which allow good mappings to be made for spatial audio, whereas channel mapping 255 is completely arbitrary.