[linux-audio-dev] JACK/ALSA cannot set capture period lower than 512 with SBLive

Lee Revell rlrevell at joe-job.com
Mon Jun 7 22:32:37 UTC 2004


Hmm, it looks like this problem was fixed in CVS a few months ago:

http://www.mail-archive.com/alsa-devel@lists.sourceforge.net/msg12181.html

According to Jaroslav, you should be able to read and write any size
periods, but there was an ALSA bug preventing this from working.

I will try this and post my results.

Lee 

On Mon, 2004-06-07 at 17:43, Robert Jonsson wrote:
> måndagen den 7 juni 2004 23.02 skrev Lee Revell:
> > Hey,
> >
> > It seems to be a known issue that you cannot run JACK with the capture
> > period size lower than 512 with the SBLive ALSA driver.  See this
> > thread:
> >
> > http://ccrma-mail.stanford.edu/pipermail/planetccrma/2003-December/003764.h
> >tml
> >
> > and this:
> >
> > http://www.music.columbia.edu/pipermail/linux-audio-user/2003-April/004040.
> >html
> >
> > The above threads seem to indicate that this is a hardware limitation.
> > However it seems to me more like a driver issue.  Using the kX drivers
> > (on Windows, http://www.kxproject.com) with the exact same card, an old
> > SBLive Platinum, Ableton Live is usable with the record and playback
> > period sizes (set via ASIO driver config) at 64 samples (2.33 ms
> > latency) with nothing else running, and rock solid at 128 (~5 ms) in the
> > face of basically anything you throw at it.  Of course it crashes, as
> > it's Windows, using an alpha quality third-party driver, but is quite
> > usable in a live music setting.  512x2 is not really usable for my
> > purposes.
> >
> > Is this assessment correct, and if so, can someone familiar with the
> > SBLive ALSA driver give me an idea as to how this could be fixed?  Could
> > this be done via ALSA config files maybe?
> 
> Your assessment is probably correct, I've brought up this issue a few times 
> before. Fact is the ALSA driver for emu10k1 does not allow to set the capture 
> buffer smaller than 512. Exactly why is still unknown, atleast to me. 
> Unfortunately I don't think it can be solved with configuration.
> 
> Talking to the kx people would probably be a good idea if you wish to dive 
> deeper into this issue. The ALSA lists is another place to try.
> 
> Regards,
> Robert
> 
> 
> >
> > Lee




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