Routing voice and hifi stereo audio from Jack into zoom under linux mint
Mostly a note to self, but maybe this is useful for someone else trying to get hifi audio from jack into zoom using linux mint or similar, so I thought I’d make it a blog post.
Zoom processes voice separately from desktop audio. So to send music and voice separately, while jack audio is running, you have to have two feeds going from jack to pulseaudio.
I already have jack set up to connect to pulse, so desktop audio works as normal. I think this was just a case of installing the `pulseaudio-module-jack` package, and configuring jack to run `pacmd set-default-sink jack_out` after startup.
To add a separate stereo channel out of jack into pulseaudio, I ran
pacmd load-module module-jack-source channels=2
Then the new jack sink appears in qjackctl and I can connect up my music sound source (supercollider) to that.
In zoom I then share a window, with stereo hifi audio switched on. `pavucontrol` is super useful at this point, you can see zoom is listening separately for voice and desktop audio, which appears as
zoom_combine_device. Unfortunately I couldn’t simply connect the
zoom_combine_device to the new jack source, don’t know why. However it’s possible to create a ‘loopback’ device for connecting sources to sinks in pulseaudio. I tried with this:
pacmd load-module module-loopback channels=2
Now I expected to have to more in pavucontrol to connect this up to zoom_combine_device, but somehow it did this automatically. I think I had to connect it to the second jack source but everything else ‘just worked’ somehow. Lucky me.
With a bit of experimentation I can hear that as expected, supercollider sounds different, depending on whether I connect it to the voice or desktop audio input into zoom.
I’ve only tested by recording a solo zoom session so far, and can hear there’s more dynamic range with desktop audio. However I can’t hear it in stereo, which is really what I’m after. I’m hoping that’s just zoom recording in mono for some reason, and that in practice it will be in stereo.. After further tests, it all works very well, with hifi, stereo audio from supercollider, and voice treated as voice. So be aware that the record function in zoom does not have the same audio as the other person hears.. Great! I think though that both sides need to have stereo enabled in the zoom settings for the other party to hear it in stereo – I’m not 100% sure that this is the case, but it’s what I’ve read..