Record from Soundcard

Find the audio source using the name and description, using the Source #ID - 1:

pactl list sources

Then record using the ID, for example if our source is Source #7:

parec -d4 --file-format=wav output.wav

Then convert to mp3:

ffmpeg -i output.wav -vn -ar 44100 -ac 2 -b:a 192k "output.mp3"