[ale] Audio from different apps to different destinations

[Alex Carver]

How does one set up the audio subsystem to route audio from a particular 
application to a particular output device? Right now I can only go to 
the sound configuration panel and select a particular device which sends 
all audio to it. Similarly for audio inputs.

What I want to do is be able to choose by application: e.g. send audio 
from the web browser to the sound card line output/headphones while 
sending the media player output to the speakers in the DisplayPort 
monitor. In the audio input case I'd want an application like the 
browser to use the microphone in the webcamera but let the audio 
recorder application listen to the microphone jack on the sound card.

This is Debian trixie. Audio in general works, it's just routed in an 
all-or-nothing configuration with no per-application granularity.