[Ffmpeg-devel] alsa input / output

Luca Barbato lu_zero
Sat Mar 24 11:58:53 CET 2007


Vladimir Mosgalin wrote:
> Hi Luca Barbato!
> 
>  On 2007.03.24 at 09:57:15 +0100, Luca Barbato wrote next:
> 
>>> True. But 1) there is no sound server as advanced as alsa and
>> pulse-audio, jack...
> 
> jack provides low-latency sound output and can do simple multi-channel
> routing, but can't do sample rate conversion, advanced routing (well you
> can use some external jack client that changes your stream, but this
> is way to complicated for this task), AC3 conversion and other stuff.

not really complicated, just done properly (as in "bloat it as you like,
but the core is minimal")

> And that's good - when I use jack, I want things to be as simple and as
> pure as possible.

eh...

> 
> As about pulse-audio - it still doesn't provide all these features, and
> after spending a few hours, I never managed to get it working in my
> configuration (outputting sound to jack). Though probably
> (application->pulse->jack->alsa) should work nicer than
> (application->alsa->jack->alsa) due to the way jack works, with rate
> conversion and most other stuff done by pulseaudio instead of alsa, the
> problem is that most application don't support pulse-audio - even though
> it's clearly the nicest all-around sound server, it's not supported even
> by mplayer, which has nearly all sound drivers in existence..

It should have something, maybe not committed since the polyp->pulse
transition.

> 
> PS note that all sound servers, even pulse and jack don't use alsa raw
> devices, they use alsa-lib and access only regular hw/plughw/etc user
> configured device.

that's the bad side.

lu

-- 

Luca Barbato

Gentoo/linux Gentoo/PPC
http://dev.gentoo.org/~lu_zero





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