[alsa-devel] Compressed Audio Playback/Capture through ALSA framework

Raymond Yau superquad.vortex2 at gmail.com
Fri Mar 18 03:22:21 CET 2011

2011/3/16 Koul, Vinod <vinod.koul at intel.com>

> On Wed, 2011-03-16 at 16:08 +0530, Mark Brown wrote:
> > On Tue, Mar 15, 2011 at 11:31:18AM -0700, Patrick Lai wrote:
> >
> > > Is there a precedent for playback/capture compressed audio stream
> > > through ALSA playback/capture interface if underlying hardware supports
> > > decoder + sink & encoder + source capabilities?
> >
> > I'm not sure if ALSA is the best API to use for this - the ALSA APIs are
> > strongly oriented around data where the size is consistent in time while
> > most compressed audio formats don't do that.  There's also existing APIs
> > in userspace like gstreamer and the various OpenMAXish things to slot in
> > with, everything below those is usually black boxed per implementation.
> I would agree with Mark, our best approach would be to do a clean design
> of a new API set which takes care of both CBR, VBR and be generic enough
> for any format.

For software decode, the application can start , pause and stop at any PCM

Does the hardware decoder has any limitation on the compressed stream ?

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