22 Oct
2014
22 Oct
'14
11:39 a.m.
Hello,
On 10/21/2014 04:11 PM, Paul Davis wrote:
testing this configuration using aplay doesn't make any sense. you
apparently believe that getting glitch-free audio playback is a
trivial task ... it isn't unless you are prepared to use a lot of
buffering (which is what happens in a lot of consumer-ish software.
I've used
aplay just for an example, we have a software application
where it behaves the same way.
you are also attempting to use ALSA dmix facilities, which is not
recommended by anyone for any purpose (distributions that used to use
this now use pulseaudio to accomplish multiplexing streams to a single
hardware device).
it is certainly possible to play streams to multiple devices at once,
but if you expect utilities like aplay to do this correctly on an
arbitrary system, you are mistaken. your problems could be in the ALSA
dmix layer, or your kernel or your overall system configuration (see,
for example, this list of problem areas:
http://manual.ardour.org/setting-up-your-system/the-right-computer-system-f…)
dmixing is no problem on MB Intel HDA sound device, but I know that
there should be a difference in setting up a professional audio device
you haven't really described what your application area is, but if it
involves multiple appplications sharing an audio device and using low
latency, then i think most people would suggest you look into JACK,
either to use it directly or as a code model (remembering, however,
that is is released under the GPL).
we have a bad experience with Jack: we were
running jack on a computer
with external and internal sound cards simultaneously. Jack was
complaining that there is no clock sync (since there is no clock sync
possibility on internal HDA / sound blaster sound cards).
Thank you for your ideas.
Vaclav