fix: routing assumption basis of microphone loopback detection

[xuan25]

The streamer refused me to set game audio and microphone to the same device when I was using a custom device.

I can see in the VB cable it may create a loopback problem, where device A's output will be loopback to A's input. But for custom devices, it shouldn't be an issue, as people can route the steam manually within the audio interface.

For example, in my case, Speaker CH 1-2 is my main output that routes to my physical speaker, and Microphone CH 1-2 is my main input, which aggregates streams from both my physical microphone and Virtual Speaker CH 5-6. In this case, I don't see any issue if I set Microphone CH 1-2 as SteamVR's mic which obtains microphone stream via Virtual Speaker CH 5-6.

[xuan25]

resolve #1070

[Vixea]

jeez thats a old issue

[xuan25]

jeez thats a old issue

Yeah, it's been around for a while. It kept popping up and bothering me from time to time when I require a mic steam.

[zmerp]

Beside the code style, I wonder why are you getting input/ouput as same device if you use "MAYA22 CH 1-2" and "MAYA22 Virtual CH 5-6"? if you see them as separate devices on windows then it means they should not be detected as same device.

[xuan25]

Beside the code style, I wonder why are you getting input/ouput as same device if you use "MAYA22 CH 1-2" and "MAYA22 Virtual CH 5-6"? if you see them as separate devices on windows then it means they should not be detected as same device.

Because my game audio is output to MAYA22 CH 1-2 (Speaker device) (not in the screenshot), thus alvr_audio::is_same_device(&game_audio_device, &source) is evaluated to true. But the game audio will never loop back to MAYA22 CH 1-2 (Microphone device) in my case, which will not lead to game audio being captured in the in-game communication.

MAYA22 Virtual CH 5-6 (Speaker device) is where I expect mic audio from the headset will be "played back" so I can route and process it with my audio interface, which then finally feeds it into in-game communication stream via MAYA22 CH 1-2 (Microphone device).

[zmerp]

Interesting, so this MAYA22 system handles playback and loopback separately? Sounds non conforming maybe but that's alright

[xuan25]

Interesting, so this MAYA22 system handles playback and loopback separately? Sounds non conforming maybe but that's alright

Thank you for your attention and assistance to the problem I encountered.

Yeah, it is actually quite similar to a Voicemeeter Banana (with physical ports) where you can select the audio stream taken from which device and being sent to which device for each bus. Technically, it is like a built-in virtual jumper cable or an Audio Video Bridging (VAB).