How to mute soundplay_node?

[5tan]

This is bug or feature request.

I would like to add "mute" capability to robot using ReSpeaker as audio output.

Unfortunately system mute button doesn't work when I use soundplay and reaspeaker. This is weird because when I use sound_play with sound card on my laptop, mute button works. Also if I use ReSpeaker with other audio apps (e.g. chromium/YouTube) mute button works.

Summary:
default laptop sound card + sound_play -> mute button works
ReSpeaker + sound_play -> mute button doesn't work
ReSpeaker + chromium/YouTube -> mute button works

Any idea what is the issue here? Is this bug in ReSpeaker firmware? In sound_play? Or in some gstreamer plugin? How to verify this?

What option do you recommend to mute soundplay_node? Do you find "mute" a useful feature to add?

[knorth55]

can you check if you can change the volume level of respeaker byalsamixer?
if not, we cannot change it, probably.
Can you also try volume=0 field in SoundRequest?

[5tan]

with alsamixer no, "This sound device does not have any controls."

but with pavucontrol yes, I can change volume and mute. It works when I use e.g. chromium, but doesn't work when I use sound_play. What's the difference?

Can you also try volume=0 field in SoundRequest?

Yes, this can be workaround, but not perfect in distributed system (since sound requests might come from many source nodes).

[knorth55]

soundplay_node.py uses alsasink, which relies on alsa.
so if you cannot control volume your device from alsa, you cannot control it, probably (I'm not a alsa specialist, so I'm not 100% sure).
https://github.com/ros-drivers/audio_common/blob/master/sound_play/scripts/soundplay_node.py#L85

I found out respeaker alsa issue in github, so please ask about alsa support in the issue.
respeaker/usb_4_mic_array#39

Or another solution is to use different sink in soundplay_node.py, such as pulsesink.
https://gstreamer.freedesktop.org/documentation/pulseaudio/pulsesink.html?gi-language=c

[5tan]

Thanks @knorth55 !
Can I change sink by configuration? Or do I have to modify soundplay_node code? https://github.com/ros-drivers/audio_common/blob/master/sound_play/scripts/soundplay_node.py#L85

[knorth55]

you need to change the source code following part.
I'm not sure it will work if you simply change just one line.
https://github.com/ros-drivers/audio_common/blob/master/sound_play/scripts/soundplay_node.py#L85

[5tan]

As it turned out, I just had to install gstreamer1.0-pulseaudio (and configure my docker for pulseaudio access). soundplay_node began to use pulseaudio instantly (no changes in code required).

I am not sure how this works (how alsasink got promoted into pulsesink?), but it's fantastic finding for ReSpeaker users.

For me the case is closed, thanks!

[yuetin]

As it turned out, I just had to install gstreamer1.0-pulseaudio (and configure my docker for pulseaudio access). soundplay_node began to use pulseaudio instantly (no changes in code required).

I am not sure how this works (how alsasink got promoted into pulsesink?), but it's fantastic finding for ReSpeaker users.

For me the case is closed, thanks!

Could you explain how to change the docker archive?
i have same problem in this