Can SuperCollider work without Jack / with just PulseAudio in Ubuntu, or can Jack present an audio input as if it were in PulseAudio?

Question

I'm trying to send live audio to a neural network in PyTorch which will in turn send OSC messages to SuperCollider, but currently the PyTorch end of things isn't listening to Jack, on which SuperCollider is dependent. The NN in PyTorch receives audio just fine on default PulseAudio via a USB interface, but as soon as I add Jack to the chain it stops recognising audio in.

I'm aware that the fix might well involve digging into the settings on the NN side, but a very proficient Python programmer checked it out briefly yesterday and didn't find a solution, and if there was a way of either making Jack present the audio input as if it was via PulseAudio, or of running SuperCollider without PulseAudio, it would be problem solved.

Thanks!

Mark

Answer 1

Supercollider requires JACK for audio playback, does not appear to support playback to Pulseaudio or ALSA

presumably PyTorch can only capture from Pulseaudio and not JACK

suspect JACK is set to use USB device that would normally be capturing audio for PyTorch
would explain why device is not available in Pulseaudio

if package pulseaudio-jack is installed
Pulseaudio MAY automatically load audio connections between Pulseaudio and JACK

• Pulseaudio JACK Sink for audio playback in Pulseaudio to JACK
• Pulseaudio JACK Source for audio in JACK to audio capture in Pulseaudio

audio in JACK connected to Pulseaudio JACK Source will be sent to Pulseaudio and will appear as a recording source in Pulseaudio, similar to the USB device source if Pulseaudio JACK Sink auto-connects to 'system:capture' USB device not available in Pulseaudio directly, may now be connected again through JACK

if connection 'Pulseaudio JACK Source' is not loaded automatically in JACK, it can be added with:

pactl load-module module-jack-source channels=2 connect=0

option 'connect=0' prevents auto-connection to 'system:capture' connections

when connection is in place, supercollider output connected to Pulseaudio JACK Sink will be available in Pulseaudio for capture/recording