[alsa-devel] [Alsa-devel] Quality resampling code for libasound
rene.herman at gmail.com
Thu Mar 22 22:19:47 CET 2007
On 03/21/2007 05:38 PM, Rene Herman wrote:
> On 03/21/2007 04:34 PM, Jean-Marc Valin wrote:
>> 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? :)
I grabbed http://www.speex.org/samples/audio/male.wav and tried using a
Crystal CS4236 based card (hw:1). With an ~/.asoundrc containing:
the difference between
aplay -D hw:1 male.wav
aplay -D up1 male.wav,
Is indeed very significant.
When I tried with hw:0, an "ESS Canyon3D" (ES1970MS-3D) based card, I
was in for a bit of a suprise though. Have never been aware of it, but
it seems this card upsamples internally anyway. Both hw:0 and up0 (same
as above) sounded almost if not completely the same. I never really play
anyting other than 44100 or 48000 to the card but it's not nice. It's a
(once) expensive "TerraTec DMX"...
Resampling upfront with:
sox male.wav -r 48000 male_sox.wav resample -q
sounds somewhat like male.wav on hw:1 again (for some reason, it won't
Anyways, yes, a very significant difference...
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