[alsa-devel] start_threshold and stream controls for PCM streams

Takashi Iwai tiwai at suse.de
Mon Dec 12 15:59:57 CET 2011

At Fri, 9 Dec 2011 11:05:19 +0530,
Nallasellan, Singaravelan wrote:
> Hi,
> Would like to know how start_threshold is expected to be used in 
> single_threaded audio player? 
> I assume that in blocking implementation,  the write call will block 
> till the ring buffer becomes empty. Is it right?

Not really.  It's not necessarily to be empty.  The condition is that
the empty space becomes avail_min or more.

But, this has nothing to do with start_threshold.  The start_threshold
is the value to start the stream automatically.  When it's 1, the
stream is started immediately when something is written.  When it's
buffer_size, the stream is started when all data is filled in the

And, the write-block behavior is irrelevant with start_threshold.


More information about the Alsa-devel mailing list