[alsa-devel] period_size and relation to number of samples

[Markus Korber]

Takashi Iwai schrieb:
> At Thu, 06 Sep 2007 07:52:37 +0200,
> Markus Korber wrote:
>> [...]
>> Now, what is an application allowed to send and what not?  For example,
>> could an application only send 1024 l/r samples and is the driver
>> responsible for buffering the data?  Or must it obey the announced
>> period_size and *always* provide 2048 l/r samples?
> 
> No, as mentioned, the app is free to send any size in general.  When
> the period size is filled up, basically it's supposed to be playable.
> But, the procedure "fill the whole buffer then start" is the most
> robust way.  
> 
> The period size is the minimal chunk size that controls the poll
> frequency.  So, it's natural to send in this size.  It's no
> requirement but a common use case.

Thus, is it possible to buffer the data in ALSA before sending them to 
the driver, in such a way, that the driver always receives period_size 
samples, regardless of what the application sends to ALSA?  And how 
would I configure ALSA for such a setup?

Regards,
Markus Korber