Hello everyone.
I was in the need for ffmpeg to output directly to JACK, which is not
supported upstream.
(It has JACK input support, as in recording something from JACK and feed
it to something else, but not the other way around)
After trying a couple of methods that didn't work so great, like fifos
or bridging through alsa loopback, I just went ahead and implemented
this part in FFmpeg.
You can find the relevant code at
https://github.com/falkTX/FFmpeg/tree/n4.4-jackoutdev
Not yet submitted upstream, still doing some testing.
If this is something useful for you, feedback / comments on the code is
very welcome.
The relevant part sits at this file
https://github.com/falkTX/FFmpeg/blob/n4.4-jackoutdev/libavdevice/jack_enc.c
Have a great weekend!