Currently Safari only supports stereo in Opus audio tracks (see T304624), and the transcodes have been adjusted for max compatibility to downconvert to stereo. It would be nice to support surround configurations, however the limit on Opus output (and lack of multichannel in MP3) means we'll probably need to use AAC output (see T166025) for wider compatibility.

This is probably fine but needs a file format legal check.

I guess we'd want to check the channel count and produce in addition to the stereo downmix, a multichannel output with the native channel count (or... possibly... normalize to 5.1? ???)

This is relatively low priority given how spotty surround playback is on computers and phones, but a nice to have.

As always, anything in the original file is preserved in the original download if you grab it for offline usage or conversion.