Eric Peters wrote: > I'm a bit confused by the alsa documentation. I want to fill up a buffer > of a alsa device with snd_pcm_writei and then if the buffer is full, I > want to be able to start the playback manually. By looking to the > documentation, I found the method snd_pcm_sw_params_set_start_threshold. > In some other messages on this list there was the hint to set this > threshhold larger than the max_buffer_size and then the device shouldn't > start automatically. So I've done. But unfortunately the playback starts > again automatically. What are the contents of /proc/asound/card?/pcm0p/sub0/sw_params during playback? > /* calculating the number of frames of a buffer and a period */ > buffer_frames = buffer_time * sample_rate; > period_frames = period_time * sample_rate; Is this correct? Aren't the xxx_time variables in microseconds? > snd_pcm_sw_params_set_start_threshold(..., 2*buffer_frames) This is OK, but it is common to use just the boundary value instead of some explicitly calculated value. > - I think, if I don't call snd_pcm_start there should be no output if > the start threshold is larger than the max_buffer_size. Is this correct? ... if the start threshold is larger than the current buffer size, in frames. Yes. > - Is it possible that the starting behaviour depends on the hardware I'm > using? No, the software parameters are hardware independent. Regards, Clemens ------------------------------------------------------------------------- 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 _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-devel
