On Monday 17 November 2014 15:09:14 David Henningsson wrote: > > Thanks for the tests. I think I misunderstood delay: I thought of delay > as having 20 ms of zero samples in the beginning, but instead soxr will > refuse to give you any samples out until you have fed it with 20 ms of > samples in. Correct? Yes, that's right. Speex also has the same behavior, if you call speex_resampler_skip_zeros() on the context. AFAIR, ffmpeg also works the same way. > So then the variable delay would not result in artifacts, it will just > be difficult to predict how many samples you'll get from the resampler. > > I'm wondering if we then need to override pa_resampler_request to do > something different for soxr? Is there a way you can ask soxr to do the > equivalent of pa_resampler_request, i e, give you an answer to "how many > samples do I need to input if I want x samples of output"? Hmm, I don't think there is. I mentioned soxr_delay() earlier, but it works post-factum (i.e. returns the current delay). I didn't see any other delay- related API. You could probably implement a repacketizer in the resampler to guarantee that the frame size is constant, and then use soxr_delay() as the approximation, but even then it probably wouldn't work for a few frames in the beginning, while the resampler is filling.
