2010/1/31 Louise Hoffman <louise.hoffman@xxxxxxxxx> > Dear ALSA developers, > > When I compile ALSA's pcm_min.c[0] example with > > gcc -Wall -lasound pcm_min.c -o pcm_min > > Everything is fine, but running it, I get the white noise as expected, > but I also get this warning/error: > > Short write (expected 16384, wrote 7616) > > Which comes from the last if-statement. > > One bug is in this line > > frames = snd_pcm_writei(handle, buffer, sizeof(buffer)); > > where "sizeof(buffer)" should be "number of frames in the buffer". > > But there are still some strange things going on. I still get those > errors, and if I remove the for-loop, nothing is played. > > Here is my code. [1] > > Can someone see what's wrong? > > Hugs, > Louise > > > [0] > http://www.google.com/codesearch/p?hl=en&sa=N&cd=1&ct=rc#4FSOSMZ6Pxc/distfiles/alsa-lib-1.0.14rc2.tar.bz2|ZScnKi-LryE/alsa-lib-1.0.14rc2/test/pcm_min.c&q=pcm_min.c<http://www.google.com/codesearch/p?hl=en&sa=N&cd=1&ct=rc#4FSOSMZ6Pxc/distfiles/alsa-lib-1.0.14rc2.tar.bz2%7CZScnKi-LryE/alsa-lib-1.0.14rc2/test/pcm_min.c&q=pcm_min.c> > > [1] http://pastebin.com/m2f28b578 > > The correct way is to use snd_pcm_get_params() to get buffer_size and period_size *snd_pcm_set_params() has limitation The most common sound card (e.g. HDA ) has the following constraints on period bytes and buffer bytes snd_pcm_hw_constraint_step(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 128); snd_pcm_hw_constraint_step(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 128); * you cannot get exactly 0.5 second period time when rate is multiple of 3 ( e.g. 48000 Hz ) _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
