Algorithm to mix sound

Question

I have two raw sound streams that I need to add together. For the purposes of this question, we can assume they are the same bitrate and bit depth (say 16 bit sample, 44.1k

Answer 1

This question is old but here is the valid method IMO.

1. Convert both sample in power.
2. Add both sample in power.
3. Normalize it. Such as the maximum value doesn't go over your limit.
4. Convert back in amplitude.

You can make the first 2 steps together, but will need the maximum and minimum to normalize in a second pass for step 3 and 4.

I hope it helps someone.