firefox sounds

>>62080034
Only if you can make the sound go in two separate output devices, which is not possible to do in firefox. You'll have to go with two browsers, like firefox and chrome and use OBS which can separately record from two different applications

>>62080092
and if i'm able to launche 2 separate firefox (for example a session offirefox 50 then a session of firefox 51) i'll do right isn't it ?

i launch a session of a portable version of firefox, to record a stream, and a session of an installed firefox to surf. Using OBS to record, is there a way to "mute" sound of the portable version and still record the sound correctly ?

>>62080034
Yes

>>62080034
Install pulseaudio