On Mon, Jan 08, 2018 at 04:01:15PM -0800, Matthias Kaehlcke wrote:
Due to different issues in our audio recording path I couldn't test this properly, and only looked at the .wav data in audacity, which appeared to look ok. After putting some of the missing pieces together and I noticed that mono capture doesn't work as intended, the recorded audio is slowed down. I think this is because the I2S controller keeps generating a two-channel stream, however the sound system interprets it as a monophonic stream because of the channel configuration.
That seems odd - I'd expect underruns somewhere?
Not sure if there is a clean solution for this if we can't tell the hardware to generate a single-channel stream. Any suggestions or do we have to revert the patch?
It sounds like a very standard problem with I2S devices, it's a fundamentally stereo format after all. If you can't get it to discard the second channel there's probably not much doing.