From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Courtier-Dutton Subject: Re: problems with mono audio. Date: Thu, 11 Mar 2004 19:48:21 +0000 Sender: alsa-devel-admin@lists.sourceforge.net Message-ID: <4050C285.3000706@superbug.demon.co.uk> References: <4050B98D.3030104@superbug.demon.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Errors-To: alsa-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: Jaroslav Kysela Cc: alsa-devel@lists.sourceforge.net List-Id: alsa-devel@alsa-project.org Jaroslav Kysela wrote: > On Thu, 11 Mar 2004, James Courtier-Dutton wrote: > > >>Which devices can a mono stream be played on? >>It seems that the only device a mono stream can be played on is the >>"default" pcm device. >> >>Devices like "front" and "rear" are stereo only devices. >>It would be nice if alsa-lib would open one of these devices, and if the >>application tries to set 1 channel instead of 2, then somehow make >>alsa-lib do the duplication of the channels. >> >>A similar thing should happen for "surround40" device. If 1 channel is >>asked for, alsa-lib should duplicate it for all channels. If 2 channels >>are asked for, then alsa-lib should create 4 channels automatically. >> >>alsa-lib seems to manage to do this sort of thing for sample rates, and >>sample formats, why not number of channels ? > > > Have you tried 'plug:front' combination ;-) > > Jaroslav > Yes, I tried all sorts of combinations. When I play a mono stream to the "front" or "rear" device I get no sound at all, but the hw_params for 1 channel is accepted, so my application thinks it should work. This has been tested with aplay. The sample file used was recorded with the command: - arecord -fS16_LE -c1 -r48000 test1.wav and played back with: - aplay -Dfront test1.wav Playing WAVE 'test1.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Mono 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