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

[Takashi Iwai]

At Wed, 21 Mar 2007 17:38:21 +0100,
Rene Herman wrote:
> 
> 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.

Well, my (latest) prpoposal is:

- keep speex resampler in alsa-plugins tree
- installing this plugin automatically enables it as the default rate
  converter without touching any configuration

The second part is missing right now.

In this way, distro simply needs to build alsa-plugins-pph package and
install it as one of default packages.  alsa-lib tree could be still
built without speex.  So, the package dependency is no longer big
problem.


Takashi