Hi Takashi, thanks for your answer, On Thu, 2007-06-14 at 12:39 +0200, Takashi Iwai wrote: > > I have a quick question regarding the filling of the usual ring buffer > > in RAM (used by sound controllers via DMA), just to be really sure: > > > > Is it true, that ALSA always writes (via mmap'ing) _whole_ periods? > > The whole buffer is, of course, used. Otherwise you'll get obvious > noises :) > > But if you're asking about the timinig, then no. How much data is > written at which timing isn't strictly defined in mmap mode. The > PCM core just checks the available size at each > snd_pcm_period_elapsed(), and reports XRUN if needed. That's all. Ok, ahm, I think my question was not about what I really wanted to know - sorry. I have to reformulate it: In fact I would like to know, how the ALSA-library mmap code behaves regarding the last chunk of samples, for example: Consider aplay, playing a wav file and the wav file's size/number of samples does _not_ fit to a multiple of a period's size. Then, does the mmap code copy these last samples as is _or_ does it copy one whole last period (which is filled with zeros)? Thanks, Joachim
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