search for: sampof

...akers). On each event (sampling capture position passed a marker in the buffer): - Fetch hardware sample-accurate sampling position of card A and B as PosA and PosB. - Copy 320 samples from buffer of card A at offset WantPosA into "mic input". - Calculate "negative offset" SampOfs = PosA-WantPosA. - Copy 320 samples from card B at offset PosB-SampOfs into "speaker input". - WantPosA += 320 - Wait for next event and repeat. This means that even if the cards drift a little (and they do, even with identical cards), the drift is compensated for. Kind of. The dow...

To everyone on the list: do *NOT* attempt to do echo cancellation with signals sampled using different clocks. This will *NOT* work. Just a 0.1% difference between the two sampling rates (it's sometimes worse than that) means that the impulse response drifts by 8 samples every second. There's just no way to efficiently track this. Or at least no way that doesn't involve something 100x