Initial volume appears to do nothing

[Willyarma]

I was just experimenting with audio_device, mixer_device and mixer_control_name. I had a hard time trying to figure out what names to put for these, but I figured it out in the end.

cheap USB audio device:

audio_device: plughw:3,0 mixer_device: default:3 mixer_control_name: Headphone

rpi4 built in output:

audio_device: plughw:0,0 mixer_device: default:0 mixer_control_name: PCM

However it appears that putting initial_volume: 100 (which is default anyway) in the config.yml doesn't change the volume at all. I assumed its supposed to set max volume at startup, have I misunderstood this?

If I query the volume with a GET request to /player/volume, its coming back with whatever it was set to before, not 100, (so go-librespot doesn't think its a 100 when its not, i mean)

I was setting the volume to low with alsamixer and then starting up go-librespot to see if it went up again.

It not a huge problem for me because if I send a POST request to /player/volume with {"volume":100} in the body (stringified JSON) this works and I can just do this from my own program.

[Willyarma]

I noticed after that others have open similar tickets, sorry if I have created a duplicate or misunderstood something. Looking at PR #51 it seems its by design that initial volume does nothing when a mixer if defined.

What I want is for the Alsa volume to be at full always as I want a fixed line output. I guess I could do this using the amixer command myself.

What would be nice is a separate API endpoint or an extension to the existing /player/volume to separately set the mixer volume and have a separate configuration parameter for initial mixer volume. (Useful when external_volume is true)

[Willyarma]

Just so its clearer to others, here are my findings:

If no mixer is configured in the config.yml then the volume control is done in software, there is no control over the hardware volume, initial_volume works in this case.

Defining a mixer stops initial_volume working but the app slider controls the mixer volume and vice versa.

external_volume: true totally stops all volume control working, but it does pass the slider position in the app through the websocket, which is really handy for controlling a seperate controllable audio amplifier / receiver.

[devgianlu]

@Willyarma What you are describing in the last post is correct. I don't see any bug in the initial_volume not affecting the ALSA mixer because it would be a bit strange if, for example, the daemon restarts and updates the volume for no reason. I'll make sure to add a note about this.

Regarding the API, I think go-librespot should not provide an endpoint for controlling the underlying audio backend directly as that can be done via other means.