On Wed, May 28, 2008 at 9:04 AM, James Courtier-Dutton <james.dutton@xxxxxxxxx> wrote: > 2008/5/28 Paul Adolph <padolph@xxxxxxxxx>: >> Is there any way to divine a count of samples that leave the ALSA ring >> buffer during playback? My application requires that I send a callback >> when a buffer-full of data is actually played for it to do A/V sync >> correctly. Right now I'm doing math to figure out the right clock >> time to issue the callback, using the latency value from >> snd_pcm_delay(), but this is not working very well. >> >> Thanks in advance. >> > > I don't know what sort of A/V method you are using, but needing a > callback for it seems wrong to me. Tell me about it. I'm porting an existing system to a new platform and unfortunately this is the model I'm stuck with. > snd_pcm_delay() gives you a way to calculate the delay between you > writing samples to the buffer and them actually arriving at the > speakers. You can therefore calculate the exact time a particular > sample will reach the speakers, and work out the A/V sync required > from that. This is how xine works to achieve A/V sync. OK - that is the method I'm using. Good to know that it is used elsewhere with success. There must be a bug in my code somewhere. Thanks for your help. ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
