No sound when monitoring

[w-g]

Hello.
I have OBS Studio 26.1.2 installed on a Debian system, and can't get sound monitoring to work.
This is the setup:

• I do not have pulseaudio (had too many problems and it never worked reliably, so I removed it)
• I have alsa and jack, and I can use both to play sound files with mpg123, mpv and other programs
• In OBS Studio, I have created a Scene and included a single Source -- a Media Source (mp3 file).
• In Settings->Audio, the only option for "Monitoring Device" is "Default"; and the only option for the "Global Audio Devices" is "Disabled". Since I'm testing only sound monitoring, I suppose this is OK.
• In Advanced Audio Properties, the Media Source is set to be monitored ("Monitor and Output")

But I hear no sound, even though the meter in the Audio Mixer shows activity.

I would expect it to work with either alsa or jack, but only input seems to work: I can add an Alsa Capture Device, and it works; if I add a JACK Input Client, it also works for capturing the mic input. But even if I remove all input sources and leave only the Media Source, I hear nothing on the connected headphones (and since there is only one option for the monitoring device, this would not be the issue).

The audio goes to the recording (shows up in the .mkv file); only monitoring doesn't seem to work.

How can I debug this? Does OBS Studio require pulseaudio for monitoring, or can it use jack or alsa?

The logs are here: https://obsproject.com/logs/MDjchim4d2Q6AxAk
And another session, when I recorded a few seconds: https://obsproject.com/logs/kSqq97ZkgYlDk2Hh

I appreciate any help with this -- thanks!

 

[richardash1981]

If you look at https://github.com/obsproject/obs-studio/blob/master/libobs/CMakeLists.txt around line 418, you will see that audio monitoring is only implemented for PulseAudio on POSIX platforms - which is a pain, but gives a starting point for the code which needs to be written to make it work.

 

[AaronD]

I figured as much, but didn't actually know. Thanks for confirming, as annoying as it is.

I wouldn't mind seeing a permanent JACK client in the Global Audio options, going both directions. Maybe even several of them. But there aren't any of those either. You can put one in a Scene, but it goes away when the scene is inactive, and most connection managers don't restore the connection when the client comes back, which leaves it silent even though it worked the last time it was shown.

So yes, the only way to work with audio in OBS is PulseAudio. And probably PipeWire when it becomes mainstream, because it emulates both PA and JACK at the same time. No change to apps that use either one.