From: Daniel Mack <daniel@caiaq.de>
To: jassi brar <jassisinghbrar@gmail.com>
Cc: alsa-devel@alsa-project.org
Subject: Re: New Audio Driver Design
Date: Mon, 20 Jul 2009 08:56:39 +0200 [thread overview]
Message-ID: <20090720065639.GA19257@buzzloop.caiaq.de> (raw)
In-Reply-To: <1b68c6790907151713y21148275t1768dbb5c6761c43@mail.gmail.com>
On Thu, Jul 16, 2009 at 09:13:28AM +0900, jassi brar wrote:
> On Thu, Jul 16, 2009 at 5:22 AM, Daniel Mack <daniel@caiaq.de> wrote:
> > Are these decoder instruction something you need to do at runtime? Or
> > would it suffice to provide them once when the driver is probed?
>
> The decoder insn, params atleast, depend upon the mp3 file i want the dsp to
> decode and play.
> So, let us assume, i have to load decoder insns and params into the dsp for
> every mp3 file playback.
Then the alsa control API seems appropriate. Unless there is any other
interface for that specific purpose I'm not aware of.
> Also, by what interface name(like I2S/PCM/AC97) shud my driver get encoded
> mp3 data from my mp3-player and then decode that mp3 data by dsp and play
> the output pcm stream?
> I am afraid i must bypass/hack ALSA stack to directly get mp3 data from
> user-space. Am i right?
Have a look at include/sound/pcm.h - there are more formats defined than
just linear PCM, and I think SNDRV_PCM_FMTBIT_MPEG could be something
you can use. But I'm not sure and never used something like that before,
so maybe anyone else can elaborate more?
Daniel
prev parent reply other threads:[~2009-07-20 6:56 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-14 4:52 New Audio Driver Design jassi brar
2009-07-15 20:22 ` Daniel Mack
[not found] ` <1b68c6790907151713y21148275t1768dbb5c6761c43@mail.gmail.com>
2009-07-20 6:56 ` Daniel Mack [this message]
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