[LAD] jack transport change accuracy for looping

[Paul Coccoli]

On Sat, Nov 19, 2011 at 10:15 PM, Iain Duncan <iainduncanlists at gmail.com> wrote:
> Just wondering if I understand this correctly. I making a loop based app for
> step sequencing. When I previously did this in Csound, I clocked it off a
> phasor, so the timing was sample accurate ( but that brought all it's own
> issues to be sure ). I'm wondering whether I should do the same thing in
> jack app, or use the jack transport clock, or some hybrid.
>
> My question, am I correct in understanding that if I use the jack transport
> position to rewind in time, I'll get:
> C) any other clients with running audio looping back to ( may or may not be
> desirable )
> B) a jitter based on the amount of time left between when the loop should
> end and the end of the frame buffer in which the loop length runs out?
> Has anyone solved B? Could it be done by some complex tempo cheating trick?
> Does anyone have any methods they've used for tight timing of looping in a
> jack app?
> Pointers at code appreciated of course. =)
> thank!
> Iain
>

Can you use the same approach you did in csound, using
jack_transport's BBT info to run your phasor?  It would require that
some app set a tempo and time signature, of course.  I use klick, or
gtklick (which has a tap tempo feature), to do this.