[PlanetCCRMA] Alsa and frames size

Fernando Pablo Lopez-Lezcano nando@ccrma.Stanford.EDU
Mon Dec 22 12:17:00 2003

> Why can't I start jack with less than 512 frames per period?
> ______________________________________________________________________
> loading driver ..
> creating alsa driver ...
> hw:0|hw:0|256|2|48000|0|0|nomon|swmeter|rt|32bit
> control device hw:0
> configuring for 48000Hz, period = 256 frames, buffer = 2 periods
> Couldn't open hw:0 for 32bit samples trying 16bit instead
> ALSA: cannot set period size to 256 frames for capture
> ALSA: cannot configure capture channel
> cannot load driver module alsa
> ______________________________________________________________________
> Can't find anything on that in the archives and you guy's all seems to
> be able to set the frames as low as 64!

Not all of us. With luck and hardware that supports it some people
manage to run with 64. That is more an exception than the rule. 

> Starting Jack with qjackctl. Soundblaster live! with the latest planet

Probably the card does not want to run with less. The SB Live is weird
in the sense that the output and input streams are different, the input
(record) one has less options with regards to buffer size and number of
buffers. Try running jack with the "-P" (playback only) option to see
what the playback limits are for it, most probably you will find you can
go lower if you do playback alone (not very useful, of course). 

-- Fernando