Transmit Stereo Audio

[iotku]

Since mumble-voip/mumble#4209 has been merged (and will most likely be included in the Mumble 1.4.0 release) it would be nice to have the ability to transmit stereo audio implemented into gumble.

Presumably, at a quick uninformed glance, all that would need to change would be setting AudioChannels to 2 although it might be more complicated than that.

gumble/gumble/audio.go

Line 30 in 1ea1159

AudioChannels = 1

Supposedly the "opus decoder can also automatically convert a stereo stream into a mono stream, so even if we transmit a stereo stream to an older version of mumble, it would still work." according to the author of the PR.

Regardless, it is probably sensible to default to mono still (since 1.4.0 hasn't released yet) with a configurable option to transmit in stereo.

[iotku]

Through random poking around I was somewhat successful in transmitting stereo audio without major glitches by changing in audio.go

AudioDefaultFrameSize = (AudioSampleRate / 100) * AudioChannels
AudioChannels = 2

and in writeAudio() modifying raw to
raw, err := encoder.Encode(a, len(a)/AudioChannels, dataBytes)

But there's some bleed through from the left & right channels to each other and I'm still pretty out of my depth here.

[iotku]

It appears it's due to mumble client settings, Enabling positional audio and headphones (under positional audio) check-boxes in the audio output settings appears to solve the issue with the bleeding