From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Courtier-Dutton Subject: emu10k1 capture period sizes? Date: Fri, 26 Mar 2004 14:40:53 +0000 Sender: alsa-devel-admin@lists.sourceforge.net Message-ID: <406440F5.2030101@superbug.demon.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Errors-To: alsa-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: alsa-devel List-Id: alsa-devel@alsa-project.org Extract from ./sound/pci/emu10k1/emupcm.c static unsigned int capture_period_sizes[31] = { 384, 448, 512, 640, 384*2, 448*2, 512*2, 640*2, 384*4, 448*4, 512*4, 640*4, 384*8, 448*8, 512*8, 640*8, 384*16, 448*16, 512*16, 640*16, 384*32, 448*32, 512*32, 640*32, 384*64, 448*64, 512*64, 640*64, 384*128,448*128,512*128 }; This makes the minimum period size that I can record from the MIC to be 384 frames. I would like period sized to be 20ms (Used by the GSM codec) in length for a VoIP application I am working on. VoIP generally works with 8000Hz sample rate to match that on Telco ISDN/Digital trunk lines. If the sample rate is 8000Hz, a period size of 384 frames makes for a 48ms which would add too much latency to the conversation. Ideally I would like to set the minimum period size to be 160 frames which is 20ms. Is there any technical reason why I cannot just add 160 to the table above? If it is ok, can someone please add it to the alsa-driver tree. Cheers James ------------------------------------------------------- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click