[alsa-devel] [Alsa-devel] Quality resampling code for libasound

Rene Herman rene.herman at gmail.com
Wed Mar 21 17:38:21 CET 2007

On 03/21/2007 04:34 PM, Jean-Marc Valin wrote:

>> Users of these distributions would then have to be fairly familiar with
>> alsa to know they could improve sound by recompiling alsa-lib against
>> the speex libraries, but given that it's (also) dirt cheap soundcards
>> that need the resampling, their users aren't too likely to _be_ fairly
>> familiar. They'd just observe (still) that their sound is "much better
>> on windows".
> Oh, I meant using a copy of the pph code in the mean time, not the
> current linear interpolation resampler.

Mmm, I believe Takashi Iwai was though. If I interpreted him correctly 
he proposed to optionally link libasound against libspeex (libresample?) 
if so ./config-ured and found at alsa-lib compile time but to keep using 
the current resampler when not.

Given the idea that distributions probably don't want their alsa-lib 
package dependent on their speex package (alsa-lib is right above the 
kernel and mandatory on any Linux system wanting to do anything with 
sound while speex is significantly higher up on the chain) I worried 
this would mean your code wouldn't be used in practice.

>> If the standard code is as lousy as I've read in this thread,
>> keeping it as default is probably not the best thing.
> It's worse than you think :-) Try playing an 8 kHz file to a
> soundcard that only does 44.1/48. It's just horrible.

Trouble is that I don't have a soundcard that can only do 44.1/48. I'll 
go hack up a driver to pretend I do though and try. Have a nice 8 kHz 
file I can try with? :)


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