From: David Henningsson <david.henningsson@canonical.com>
To: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Cc: 'ALSA Development Mailing List' <alsa-devel@alsa-project.org>
Subject: Re: USB Audio questions
Date: Tue, 16 Aug 2011 07:30:53 +0200 [thread overview]
Message-ID: <4E4A008D.60907@canonical.com> (raw)
In-Reply-To: <000001cc5b8a$4a6577c0$df306740$@bossart@linux.intel.com>
On 08/15/2011 10:31 PM, Pierre-Louis Bossart wrote:
> - Increasing the number of packets/urbs solves my power issue but not the
> synchronization issue. If I reduce the number of urbs to reduce the
> interrupt rate, then the accuracy of the hw_pointer is decreased big time
> and it becomes difficult to synchronize with video.
I think the same thing is a problem for quite a few other devices as
well - I wonder if we need some kind of "pointer granularity" variable
to be exported through the ALSA API? PulseAudio could use that to
determine whether or not to enable timer-based scheduling. And in these
cases, maybe a call to hw_pointer could return hw_pointer and time, and
then PulseAudio etc could use that for extrapolation (or the
extrapolation could be done in alsa-lib).
--
David Henningsson, Canonical Ltd.
http://launchpad.net/~diwic
next prev parent reply other threads:[~2011-08-16 5:30 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-15 18:15 [PATCH 1/4] ASoC: DAPM: Allow multiple mixer sources to be routed via the same switch Lars-Peter Clausen
2011-08-15 18:15 ` Lars-Peter Clausen
2011-08-15 18:15 ` [PATCH 2/4] ASoC: Add ADAU1373 codec support Lars-Peter Clausen
2011-08-15 20:31 ` USB Audio questions Pierre-Louis Bossart
[not found] ` <4e498227.854fdf0a.0dd4.6281SMTPIN_ADDED@mx.google.com>
2011-08-15 20:55 ` Daniel Mack
2011-08-15 21:48 ` Pierre-Louis Bossart
[not found] ` <000001cc5b8a$4a6577c0$df306740$@bossart@linux.intel.com>
2011-08-16 5:30 ` David Henningsson [this message]
2011-08-16 6:47 ` Clemens Ladisch
2011-08-16 6:37 ` Clemens Ladisch
2011-08-16 7:30 ` Daniel Mack
2011-08-16 15:46 ` Clemens Ladisch
2011-08-16 15:38 ` Pierre-Louis Bossart
[not found] ` <20110816145353.GB5233@xanatos>
2011-08-16 15:44 ` Pierre-Louis Bossart
[not found] ` <000601cc5c2a$87a26350$96e729f0$@bossart@linux.intel.com>
2011-08-16 16:09 ` Clemens Ladisch
2011-08-16 17:19 ` Pierre-Louis Bossart
[not found] ` <000001cc5c38$b07abee0$11703ca0$@bossart@linux.intel.com>
2011-08-17 6:29 ` Clemens Ladisch
2011-08-17 15:21 ` Pierre-Louis Bossart
2011-08-19 22:02 ` Pierre-Louis Bossart
2011-08-16 20:41 ` Torsten Schenk
2011-08-16 22:11 ` Pavel Hofman
2011-08-17 6:36 ` Clemens Ladisch
[not found] ` <000001cc5c5a$e7d5c3e0$b7814ba0$@bossart@linux.intel.com>
2011-08-16 22:13 ` Torsten Schenk
2011-08-16 15:54 ` [PATCH 2/4] ASoC: Add ADAU1373 codec support Mark Brown
2011-08-16 15:54 ` Mark Brown
2011-08-15 18:15 ` [PATCH 3/4] ASoC: Blackfin: ADAU1373 eval board support Lars-Peter Clausen
2011-08-15 18:15 ` Lars-Peter Clausen
2011-08-16 15:54 ` Mark Brown
2011-08-16 15:54 ` Mark Brown
2011-08-15 18:15 ` [PATCH 4/4] Blackfin: bf537: Stamp: Register ASoC EVAL-ADAU1373 board driver Lars-Peter Clausen
2011-08-15 18:15 ` Lars-Peter Clausen
2011-08-16 15:56 ` Mark Brown
2011-08-16 15:56 ` Mark Brown
2011-08-18 13:52 ` Lars-Peter Clausen
2011-08-18 13:52 ` Lars-Peter Clausen
2011-08-15 23:25 ` [PATCH 1/4] ASoC: DAPM: Allow multiple mixer sources to be routed via the same switch Mark Brown
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