If I understand your (and other) questions correctly: You want to input (analog stereo) audio, and somehow get it thru USB?
What are you trying to achieve?
Hi ,my sole intention is for audio be it using sound card or Pi's built in 3.5mm audio jack slot or HDMI to output and passthrough audio directly to my Home Theater Sound System without any loss in quality or channels
But i did find a sollution somewhat is that LibreElec 10 Beta (Kodi 19 Matrix) allows audio passthrough from both HDMI slots with Dolby support and MultiChannel
I'm sorry if my questions are really confusing but to be honest im confused as well so that shows with my questions
But for now the issue seems to be working out as i'll test this Kodi feature tomorrow and if it works ,will mark it as solved