[alsa-devel] Fwd: HW decoding abstracted in ALSA

Harsha priya gupta harshapriya at gmail.com
Mon Feb 25 18:50:28 CET 2008

Thanks for your immediate reply.

My hardware supports MP3 decoding in HW (in addition to few others). I am
looking to write a driver such that when an MP3 file is played, the file is
decoded using the HW decoder and played. Is there a possibility in current
ALSA framework to do so?


On Mon, Feb 25, 2008 at 5:33 PM, Takashi Iwai <tiwai at suse.de> wrote:

> At Mon, 25 Feb 2008 12:27:00 +0530,
> Harsha priya gupta wrote:
> >
> > Hi,
> >
> > I am new to ALSA and audio stack in Linux. I have a sound card that can
> do
> > HW decoding as well. I am looking at writing an ALSA driver such that
> > whatever may be the player or MMF above, it should use the HW decoder
> and
> > not the inherit SW decoder that is available with the player.
> >
> > Can someone help me with some pointers or existing like-drivers?
> Which format is in mind?  In theoery, you can implement the h/w
> decoder on the ALSA framework, but there are some restrictions:
> - ALSA PCM assumes the constant bitrate
> - The format bit must be defined
> - The specific app recognizes and supports that format
> In the case of AC3 or DTS, it's embedded in SPDIF frames so the PCM
> core stuff doesn't take care of the above.  But, in the case of native
> (non-PCM) formats, the support can be difficult as is.
> Takashi



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