[pulseaudio-discuss] Fwd: Pulse Audio Sample Cache & resampling

Jean-Marc Valin jean-marc.valin at usherbrooke.ca
Tue Feb 20 14:57:13 PST 2007


keith preston a écrit :
> Ok, so I've been busy hacking away at getting the libspeex fixed point
> resampler into pulse audio.    Here is a patch that barely makes it work in
> a very hacked way.   You should be able to apply this to the tarball
> 0.9.5sources.  If you get it to build (I found a few problems with
> types so you
> might have to comment uncomment a couple of lines) you can run the
> pulseaudio daemon with the parameters --resample=libspeex:0   where 0
> can be
> 0-10 and represents quality.   A few notes

Cool!

> It only does re sampling and not channel doubling (I have some code in
> there, but it doesn't really work and probably is really bad)
> 
> There is a annoying constant clicking, which I'm sure is just a bug I
> overlooked. (Jean Marc?)

Oops, I think you've hit a bug in the short->float converter (when using
the _int() version but compiling as float) and which I fixed yesterday.
Updating svn should do it.

> I have this weird issue where the re sample will return an out length that
> is not divisible by sample_size * channels.   It tends to be odd.   What
> does this mean?

It means that the out_len is the number of samples *per* channel and so
is the in_len. i.e. if you have 4 channels of 1024 samples each, the len
is still 1024 (not 4096).

	Jean-Marc



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