[pulseaudio-discuss] Patch review status wiki page updated

[Alexander E. Patrakov]

17.08.2014 12:38, Tanu Kaskinen wrote:
> Patch review status updated:
> http://www.freedesktop.org/wiki/Software/PulseAudio/PatchStatus/

...

> Resampler quality testing
>
>     From: poljar (Damir Jelić)
>     Submission date: 2013-08-26(?)
>     In a github branch: https://github.com/poljar/pulseaudio/commits/resampler_quality

Review: does not answer the question "is this distortion audible?" and 
provides no way to evaluate quality of non-PulseAudio resamplers.

So I have decided to redo all of this using a different approach. The 
new work is based on a psychoacoustical model in order to correct the 
first objection, and is supposed to judge any resampler according to its 
output as a wav file (including Windows output recorded by KVM) when 
given a linear sine sweep. I have already implemented the model, can 
answer the "is this distortion audible" question given the spectrum of 
the signal and the distortion, but have not used this yet to analyze the 
resampler output. Damir also provided useful contributions. So this is 
definitely no longer "Waiting for Review".

As this successor is now a side project that does not share code with 
PulseAudio and does not even use PulseAudio, I don't expect it to 
produce a PulseAudio patch. If Damir agrees, let's remove it from the page.

I think I will have some announceable results in about a week and full 
results in about a month, and would like to talk about this (maybe 
unofficially) at Audio mini conference 2014.

> Resampler implementations
>
>     From: poljar (Damir Jelić)
>     Submission date: 2013-09-06(?)
>     Reviewed: 2013-11-29
>     In a github branch: https://github.com/poljar/pulseaudio/commits/resampler_implementations_v2
>     Status update: http://article.gmane.org/gmane.comp.audio.pulseaudio.general/18991
>     Performance tests (mono): http://poljar.blogspot.com/2013/08/vol-2-resampling-methods.html
>     Performance tests (stereo & 5.1): TBD
>     Bandwidth & Aliasing tests: TBD, with explanatory material at http://poljar.blogspot.com/2013/10/epilogue-fourier-analysis-and-testing.html
>     Features (such as variable-rate support, input & output formats, optimizations for particular combinations of sample rates, compatibility with rewinds): TBD

Duplicate of this one, and all TBDs still apply to the new submission 
(please copy):

> resamplers
>
>     3 patches
>     From: Damir Jelić / Peter Meerwald
>     Submission date: 2014-08-04
>     On the mailing list: http://thread.gmane.org/gmane.comp.audio.pulseaudio.general/20739
>     These have been reviewed by Arun and Alexander, and it's a bit unclear what will happen next. The first patch appears to be (mostly?) ready to be merged, the two other patches probably need at least some additional justification.

Yes, the first patch should be merged, with or without taking my 
speex_is_fixed_point objection into account. I would have to apply the 
other two patches locally in order to do the quality evaluation, but 
don't want them to be upstreamed yet, until we have tools to judge them. 
Hopefully this clears the "what's next" question.

-- 
Alexander E. Patrakov