How to record sound from a microphone and speakers in one stream?

Question

C++ / C#

I wrote a DirectShow filter to capture the sound that is playing on the system.
Written using WASAPI Loopback.
I need to record this sound and the sound from the microphone in one stream.
How to bring two streams together in DirectShow?

Answer 1

I don’t know how it is in DirectShow, but theoretically it’s easy to add both streams element by element, at the same sampling rate. If the sampling rate is different, you need to reduce to one, and then add it anyway.