[pulseaudio-discuss] GSoC Proposal: Resampling Improvements

[Damir Jelić]

Adding pulseaudio-discuss back. Sorry about that.

On Fri, Apr 19, 2013 at 07:08:46PM +0200, Damir Jelić wrote:
> On Fri, Apr 19, 2013 at 07:48:36PM +0300, Tanu Kaskinen wrote:
> > On Thu, 2013-04-18 at 15:26 +0200, Damir Jelić wrote:
> > > Hi.
> > > 
> > > For those who don't know, I'm Damir Jelić from Croatia and I would like to
> > > work on the "Resampling Improvements" project during this year's Summer of
> > > Code.
> > > 
> > > Last year I participated and finished the "Latency offset" project. After
> > > the summer I tried to become a regular contributor. For those who are
> > > interested, all my contributions can be seen in the git log [1].
> > > 
> > > I know I said that last year should be my final year as a student but I
> > > prolonged my studies for a year and I'm still eligible for this year's
> > > Summer of Code.
> > > 
> > > I picked this project because it's a part of pulseaudio that I consider
> > > quite interesting and didn't had the chance to touch yet.
> > > 
> > > I have some DSP background (although more from control theory than from
> > > digital audio) and also I have some assembly background, but not from any
> > > modern instruction set (z80), which should make me a good candidate for this
> > > project.
> > > 
> > > What I would like to do over the summer:
> > >     - enable resampling with libav
> > >     - write some test coverage for the libav resampling method
> > >     - deprecate the ffmpeg resample method
> > >     - update the speex resample method
> > > 
> > > The ideas page mentions also libresample, if I'm not mistaken pulseaudio
> > > already supports resampling via libresample and I'm not sure what would I
> > > need to do about this.
> > 
> > By "libresample", I guess you mean "libsamplerate". Peter can correct me
> > if I'm intepreting him wrong, but my understanding is that libsamplerate
> > was only mentioned as an example of a resampler with a problematic
> > license. I don't know either what should be done about it - perhaps the
> > idea was to compare the different resamplers, and if it turns out that
> > we don't have any good reason to keep using libsamplerate, we could drop
> > that code.
> > 
> 
> Yes, I've got it wrong since there are some libs named libresample.
> 
> https://ccrma.stanford.edu/~jos/resample/README-libresample-0.1.3.txt
> 
> > > Speex has been obsoleted [2] and the resampler seems to had been moved to
> > > opus-tools. There are some interesting commits [3] inside this repo and I think
> > > it would be nice to update our speex resample method although I'm not sure
> > > if it's ok to drop speex and replace it with opus-tools just like that.
> > 
> > To me replacing the speex resampler with the opus-tools resampler sounds
> > like an obvious thing to do, if the upstream says that the speex
> > resampler code is deprecated in favour of opus-tools.
> > 
> 
> Ok, sounds good.
> 
> > -- 
> > Tanu
> > 
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