18.12.2015 13:04, Georg Chini wrote: > On 18.12.2015 08:45, Alexander E. Patrakov wrote: >> 18.12.2015 11:47, Georg Chini wrote: >>> On 18.12.2015 06:49, Tanu Kaskinen wrote: >>>> >>>> >>>> Making pa_sample_rate_valid() accept values above PA_RATE_MAX isn't >>>> very nice, but I can see how it's better than the current behaviour, >>>> which probably can cause the daemon to crash. Alexander mentioned in >>>> IRC that he'd prefer doing the adaptive resampling inside module- >>>> loopback rather than using pa_sink_input_set_rate(), and this change >>>> demonstrates one good reason for that. I'm not asking you to implement >>>> that change, but it certainly would be nice. >>>> >>>> -- >>>> Tanu >>> Yes, doing it inside the module would really be a good idea. The >>> main issue my controller is fighting against are the systematic >>> errors introduced by changing the rate of the sink input. When >>> you change the rate, the next latency report has an extremely >>> high error. >>> Can you point me to some code that implements resampling >>> so that I have an example of what to do? >> >> Look at the ffmpeg resampler inside PulseAudio tree, it's the simplest >> possible one. But I'd say that it's pointless to look at the code >> without understanding the math behind all of that, so please look at >> these links, too: >> >> https://en.wikipedia.org/wiki/Sinc_filter >> https://ccrma.stanford.edu/~jos/resample/resample.pdf >> > I would first use the existing resamplers before trying to implement my > own. > So I was rather referring to the framework used in pulseaudio when using > existing resamplers. If I ever write a specific resampler for the > loopback module > it could be integrated into the normal framework. And that's exactly what I am against. Neither the normal framework nor any of the existing (even outside PulseAudio) non-GPL resamplers support sub-sample latency reporting. Please write your own resampler, that's what I meant on IRC. I know that in a similar email to you I also said "or treat the problem as unsolvable", this still stands, and Tanu's "would be nice" also allows that. -- Alexander E. Patrakov
