How to pass a fake microphone to play some audio to android

[Brijeshkrishna]

I want to test some calling features, so I need some audio in the android, how can I play some audio on the fake microphone.

I tried a bunch of things, using pulse audio, ALSA neither worked.

[Shmayro]

I'll spin up the container locally, test the audio-injection options, and see which method works best. I’ll update the issue shortly with a working setup or workaround.

[Brijeshkrishna]

Docker containers are headless Linux machine, so I can't use host audio options -allow-host-audio since there is no audio anyway.

I tried this

1. WAV backend by setting

export QEMU_AUDIO_DRV=wav
export QEMU_WAV_IN_PATH=sample.wav

This partially worked it just produced a cracking sound or buzzing sound, not the sound I passed in the wav file.

Checked sample rate and channels are correct to that default (44100hz, 2 channels).

2. PA (pulse audio)
   This is most confusing, the emulator command mentioned this as
   ALSA but the qemu mentions this as PA.

Created a virtual microphone

pactl load-module module-null-sink sink_name=FakeSink
pactl load-module module-remap-source master=FakeSink.monitor source_name=FakeMic

Set the env

export QEMU_AUDIO_DRV=pa
export QEMU_PA_SOURCE=FakeMic

Steam a audio

ffmpeg -stream_loop -1 -re -i your_audio.wav -f pulse 

This didn't work the emulater just print

pulseaudio: Failed to initialize PA contextCould not init `pa' audio driver
pulseaudio: Failed to initialize PA contextCould not init `pa' audio driver

(It actually printed twice)

I check pulseaudio was running
pactl info, it listed the devices.

I am trying to have a simple dummy microphone and stream some audio through ffmpeg and pass that to android emulator as its in-built microphone.

[jsteinberg7]

Hey @Shmayro @Brijeshkrishna was this ever figured out?

[Brijeshkrishna]

I think, I managed to get working, create the virtual sources and stream audio as described above, and launch the emulated window (GUI) -no-window won't work for pulseaudio.

Let me know you able to reproduce.

[MuhammadShamaasSenarios]

@Brijeshkrishna kindly tell me how did you stream mic audio into Redroid?

[Brijeshkrishna]

As i mentioned in the above, use the pulse audio setup. Since docker will running in headless mode you need to create a Xvfb pulseaudiio needs that (x11 screen).
Then launch the emulator and select the correct audio stream in the pulseaduio mixer