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From: Clemens Ladisch <clemens@ladisch.de>
To: Amit Nagal <helloin.amit@gmail.com>
Cc: alsa-user@lists.sourceforge.net, alsa-devel@alsa-project.org
Subject: Re: regarding setting of fragment size in usbaudio driver
Date: Mon, 13 Dec 2010 10:04:29 +0100	[thread overview]
Message-ID: <4D05E19D.7010405@ladisch.de> (raw)
In-Reply-To: <AANLkTimCg0kxCU1By9eg0Qba5hKMseS5rAZXsE_a4hOF@mail.gmail.com>

Amit Nagal wrote:
> i am using a OSS based usbaudio application for usb audio streaming .
> 
> my usb audio device is capture only device .
> 
> i want to set the fragment size of usbaudio alsa driver to reduce
> latency problem coming in my application .
> 
> currently even if my application reads 4k data from userspace , i
> observed driver will buffer for 100 ms data ( period size data )= 16 k
> at 44100 frquency
> 
> and after driver  reads 16k data , read call will return with 4k data
> .  so read() call remains blocked for 100ms which is causing some
> latency problem .

There is no extra buffer in the driver.
There seems to be something wrong with your algorithm.

Does recording with the arecord tool work?


Regards,
Clemens

  reply	other threads:[~2010-12-13  9:01 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-12-11  9:16 regarding setting of fragment size in usbaudio driver Amit Nagal
2010-12-13  9:04 ` Clemens Ladisch [this message]
2010-12-13  9:56   ` Amit Nagal
2010-12-13 13:38     ` Clemens Ladisch
2010-12-13 14:11       ` Amit Nagal
2010-12-14 16:23         ` Clemens Ladisch
     [not found]   ` <27661_1292234220_1292234220_AANLkTi=S732=Wj572Th860PpBYE0fkJ97JH2CwitZ4ah@mail.gmail.com>
2010-12-13 10:05     ` [Alsa-user] " Bill Unruh

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