From: Eliot Blennerhassett <linux@audioscience.com>
To: Patrick Lai <plai@codeaurora.org>
Cc: alsa-devel <alsa-devel@alsa-project.org>, linux-arm-msm@vger.kernel.org
Subject: Re: Compressed Audio Playback/Capture through ALSA framework
Date: Wed, 16 Mar 2011 09:40:03 +1300 [thread overview]
Message-ID: <4D7FCEA3.4070003@audioscience.com> (raw)
In-Reply-To: <4D7FB076.30300@codeaurora.org>
On 16/03/11 07:31, Patrick Lai wrote:
> Hi,
>
> Is there a precedent for playback/capture compressed audio stream
> through ALSA playback/capture interface if underlying hardware supports
> decoder + sink & encoder + source capabilities?
No. (Apart from AC3 passthrough to spdif output)
ALSA might be extended to cope with compressed audio with fixed frame
size and bitrate, but dealing with any VBR encoding is likely to be even
more problematic.
This is because alsa assumes a fixed relationship between samplerate and
data rate, and also assumes that samples fit in an integer number of bytes.
AFAIK dealing with hardware enc/dec has been done using gstreamer plugins.
E.g. http://www.lca2010.org.nz/slides/50315.pdf
Given that audioscience makes cards that support mp3 encode/decode as
well as pcm, I'd like it if alsa *did* support compressed audio...
> Which source file can I find an example?
>
> Thanks
> Patrick
>
regards
--
Eliot Blennerhassett
AudioScience Inc.
next prev parent reply other threads:[~2011-03-15 20:40 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-15 18:31 Compressed Audio Playback/Capture through ALSA framework Patrick Lai
2011-03-15 20:40 ` Eliot Blennerhassett [this message]
2011-03-15 20:52 ` [alsa-devel] " pl bossart
2011-03-15 23:28 ` Patrick Lai
2011-03-16 7:21 ` [alsa-devel] " Clemens Ladisch
2011-03-16 7:23 ` Jaroslav Kysela
2011-03-16 22:08 ` Patrick Lai
2011-03-17 7:39 ` [alsa-devel] " Clemens Ladisch
2011-03-16 10:38 ` Mark Brown
2011-03-16 10:59 ` Koul, Vinod
2011-03-16 11:56 ` Mark Brown
2011-03-16 12:17 ` Koul, Vinod
2011-03-16 17:52 ` pl bossart
2011-03-16 17:53 ` Mark Brown
2011-03-16 18:00 ` pl bossart
2011-03-16 18:08 ` Mark Brown
2011-03-17 2:21 ` Koul, Vinod
2011-03-17 5:00 ` Patrick Lai
2011-03-17 11:54 ` Mark Brown
2011-03-17 14:27 ` pl bossart
2011-03-17 18:25 ` Mark Brown
2011-03-17 19:16 ` [alsa-devel] " pl bossart
2011-03-17 20:16 ` Mark Brown
2011-03-17 21:19 ` Patrick Lai
2011-03-17 21:25 ` Mark Brown
2011-03-18 16:03 ` pl bossart
2011-03-22 13:01 ` Mark Brown
2011-03-17 5:32 ` Asus E35M1-M Pro and Realtek AL887-VD - no love from ALSA for Sourround Wojciech Myrda
2011-03-17 21:55 ` Paul Menzel
2011-03-20 10:13 ` Wojciech Myrda
2011-03-18 2:22 ` Compressed Audio Playback/Capture through ALSA framework Raymond Yau
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