ADC Soundcard hack : Increase by 2 the number of channels for any adc soundcard

Hello alsa team,

To begin, thank you all the team for what you do, the alsa-project is a wonderfull open-source project! My goal is to increase the number of channels of my adc soundcard by separate once again a left-right for one channel. Using a small electronic scheme like this (it's a first simulation try, I have to test and improve), we can multiply the number of channels by 2. [image.png] Of course, the sampling frequency will be decreased by 2 using this method. Where can I begin with alsa to increase the number of channels and adjust the sampling frequency ? Something like a virtual soundcard maybe ? I have skills in dev but don't know where I have to start with alsa fot this hack...

Best regards, Sylvain Grenier