[PD] Audio properties dialog

Miller Puckette msp at ucsd.edu
Wed Oct 8 01:47:57 CEST 2014


It could easily be that it mattered in the past and/or matters on some part-
icular hardware (I spent years fidding with ALSA trying to find magic to get 
its latency down on various devices).

cheers
M

On Tue, Oct 07, 2014 at 07:41:20PM -0400, Ivica Bukvic wrote:
> ALSA appears to have it but I notice no observable changes in perceived
> latency.
> On Oct 7, 2014 6:54 PM, "Miller Puckette" <msp at ucsd.edu> wrote:
> 
> > I couldn't immediately find anything short of going through each
> > s_audio_*.c
> > implementation and checking whether the "blocksize" parameter in the open
> > routine gets used... ugh.
> >
> > M
> >
> > On Tue, Oct 07, 2014 at 09:14:43PM +0000, Jonathan Wilkes via Pd-list
> > wrote:
> > > Thanks.
> > > Is there a quick way to figure out which APIs use it?
> > > -Jonathan
> > >
> > >
> > >      On Tuesday, October 7, 2014 5:07 PM, Miller Puckette <msp at ucsd.edu>
> > wrote:
> > >
> > >
> > >  Sorry - I had forgotten an important detail - not every API implements
> > > blocksize.  In cases where either you can't or it would never help
> > anything,
> > > it's simply left at 64.  (and really, the control shouldn't appear on the
> > > dialog when it isn't used :)
> > >
> > > I believe blocksize is most important in windows.
> > >
> > > cheers
> > > Miller
> > >
> > > On Tue, Oct 07, 2014 at 02:15:09PM -0400, Ivica Ico Bukvic wrote:
> > > > On 10/07/2014 01:41 PM, Miller Puckette wrote:
> > > > >sys_blksize() reports the block size used by Pd's acheduler (I
> > believe it's
> > > > >always 64 in valnilla but will be settable someday :)
> > > > >
> > > > >the I/O blocksize, which is set in the audio settings dialog, is what
> > > > >Pd uses to interface with whatever audio API is in use.
> > > >
> > > > Thanks for the clarification, Miller. What I am confused by is that
> > when
> > > > using ALSA and changing blocksize from 64 to 2048, there is no audible
> > > > difference in the delay, even though it should be profound enough to be
> > > > preceivable by ear. Is this because ALSA has another internal buffer
> > that
> > > > essentially supersedes either blocksize, making the final output
> > (near?)
> > > > identical?
> > > >
> > > > Also, response to Jonathan's follow-up question regarding JACK would be
> > > > appreciated. It seems from looking at the code, JACK does not care
> > about
> > > > blocksize variable but I could be easily missing something.
> > > >
> > > > Best,
> > > >
> > > > Ico
> > > >
> > > > >
> > > > >cheers
> > > > >M
> > > > >
> > > > >On Tue, Oct 07, 2014 at 05:30:55PM +0000, Jonathan Wilkes via Pd-list
> > wrote:
> > > > >>Hi list,    What does the blocksize entry box in audio dialog
> > properties do?  And how does that value relate (if at all) to the value
> > output by sys_getblksize?
> > > > >>Thanks,Jonathan
> > > > >>_______________________________________________
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> > > >
> > > > --
> > > > Ivica Ico Bukvic, D.M.A.
> > > > Associate Professor
> > > > Computer Music
> > > > ICAT Senior Fellow
> > > > DISIS, L2Ork
> > > > Virginia Tech
> > > > School of Performing Arts - 0141
> > > > Blacksburg, VA 24061
> > > > (540) 231-6139
> > > > ico at vt.edu
> > > > www.performingarts.vt.edu
> > > > disis.music.vt.edu
> > > > l2ork.music.vt.edu
> > > >
> > > >
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