[alsa-devel] Which project to choose?

Jaroslav Kysela perex at perex.cz
Wed Jul 14 17:25:33 CEST 2010

On Wed, 14 Jul 2010, David Henningsson wrote:

> 2010-07-14 13:13, Raymond Yau skrev:
>> localhost pulseaudio[24553]: alsa-util.c:   appl_ptr     : 735801008
>> localhost pulseaudio[24553]: alsa-util.c:   hw_ptr       : 735846184
>> This is underrun as you can see appl_ptr is behing hw_ptr
> Ehm, isn't that a ring buffer? I e, there is nothing wrong with appl_ptr
> being less than hw_ptr.

For playback, if appl_ptr is less than hw_ptr, it's underrun situation 
(application didn't feed samples in time to the driver's ring buffer).

Note that pointers in ALSA are in range 0..boundary not 
0..ring_buffer_size (boundary is near LONG_MAX value) - it's design to 
detect such situations (underrun, overrun).


Jaroslav Kysela <perex at perex.cz>
Linux Kernel Sound Maintainer
ALSA Project, Red Hat, Inc.

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