[Ffmpeg-devel] alsa input / output
Wed Mar 21 03:35:58 CET 2007
On Wed, Mar 21, 2007 at 12:57:20AM +0100, Michael Niedermayer wrote:
> On Wed, Mar 21, 2007 at 01:15:51AM +0300, Vladimir Mosgalin wrote:
> > Hi Rich Felker!
> > On 2007.03.20 at 16:18:19 -0500, Rich Felker wrote next:
> > Well.. sorry for OT but I really think that your point on this is VERY
> > wrong.
> > > Of couse, as an aside I strongly question the usefulness of lots of
> > > this "functionality". It seems more like bloat to me. If the hardware
> > > doesn't support a particular samplerate it should simply require the
> > > application to provide a supported samplerate, rather than doing
> > > horribly-painful-to-listen-to nearest-neighbor resampling in the
> > > library level...
> > That's exactly the problem you get with device interface; it is just
> > supposed to "work". But with alsa accessed through library interface,
> > you can do anything you desire, when your applications doesn't support
> > this. And you mean application should _always_ use built-in
> > resamplers? THAT is the right way to get painful-to-listen-to sound,
> > because most of resamplers will suck. With alsa, however, you just
> > choose whatever you want, depending on your CPU and personal choice
> > (believe it or not, but SRC_SINC_FASTEST sounds better than
> > SRC_SINC_BEST_QUALITY and all other SRC_SINC libsamplerate filters to
> > me).
> so the low quality resampler from libsamplerate sounds better to you then
> the high quality ones from libsamplerate, while i dont have much faith
> in libsamplerate i cant belive that their fast low quality code sounds
All of the resamplers in libsamplerate are horribly broken. Nicholas
Kain who sent the recent string safety patch series to mplayer-dev-eng
recently patched ALSA (and sent his patches upstream) to use the lavc
resampler instead, improving both quality (from abysmal to good) and
performance (by about twenty times). The fact that ALSA ever used
libsamplerate simply shows complete incompetence.
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