[PD] Trying to implement switch ramp

Miller Puckette mpuckett at imusic1.ucsd.edu
Thu Oct 4 16:05:09 CEST 2007

This seems to be a fundamental limitation with block-based DSP panguages -
you can get 1-sample DSP/control/DSP turnaround only if you're content to
wait for the next block boundary -- if you want to be able to name any
sample you want, then the minimum turnaround delay is one block.  I waxed
a bit on that in Chapter 3 of Techniques, but I think the subject is so
abstruse that nobody actuallly reads that chapter :)


On Thu, Oct 04, 2007 at 03:59:20PM +0200, Frank Barknecht wrote:
> Hallo,
> Thomas O Fredericks hat gesagt: // Thomas O Fredericks wrote:
> > vsnapshot~? Where can I find it's help?  (I use Ubuntu PD(not extended) and
> > PD 0.40-2)
> Sorry, I was wrong of course: As Roman correclty mentioned, it's not
> really possible to use switch-and-ramp with vline~/vsnapshot~.
> Actually I found this out as well in that past list thread, but forgot
> about it. ;) 
> > I still see inconsistencies in the patch I submitted
> > I will try to make something a little clearer: please try the new attached
> > patches and tell me why the little bit before the ramp changes size (I
> > suspect that is the size of one block, sometimes there, sometimes not). How
> > can I make this consistent?
> I attached a reworked version of that example which compares both the
> line~ and vline~ switch-and-ramp techniques. I'm now using much
> smaller delay times, so it's easier to see what's happening accross
> the block boundaries. With vline~/vsnapshot (left part) you'll see
> that the ramp starts at a wrong position. That's because vsnapshot~
> reports the signal value too late, so the original ramp already is at
> a different position. With line~/snapshot~ this doesn't happen (right
> part of patch, you need a big enough screen.)
> Ciao
> -- 
>  Frank Barknecht                                     _ ______footils.org__

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