From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Courtier-Dutton Subject: alsa resampler comstraints. Date: Thu, 21 Sep 2006 21:54:00 +0100 Message-ID: <4512FBE8.6060905@superbug.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: alsa-devel-bounces@lists.sourceforge.net Errors-To: alsa-devel-bounces@lists.sourceforge.net To: alsa-devel@lists.sourceforge.net List-Id: alsa-devel@alsa-project.org Hi, I want to document some of the constraints of the alsa resampler. Here is what I understand, and I would like someone to verify my statements before I document them. 1) The buffer and period sizes for the sound card hardware to resampler are limited to the max buffer and period sizes available on the hardware. As a result, the available buffer and period sizes vary depending on hardware utilised. 2) The resampler converts one hardware period size at a time. This results in the buffer and period size constraints explained in (1) arriving at the application as a direct ratio of source and destination sample rate. e.g. hardware has 2 periods of 1024 frames running at 48000 Hz. application will see 2 periods of 1024 * 44100 / 48000 = 940.8. This is rounded down to 940 frames. So the user application sees 2 periods of 940 frames. If user space asks for 2 periods of 1024 at 44100 hz it will fail. The above 2 points were true some time ago. Has anything changed? Kind Regards James ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys -- and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV