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
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