[LAD] External midi sync

[Paul Davis]

On Sat, Jan 23, 2010 at 1:23 AM, Tim E. Real <termtech at rogers.com> wrote:
> I can imagine sync was a tougher nut to crack in Ardour.
> MusE's ticks per quarter note is fixed at 24, although
>  the 'frames per quarter note' (hence division) is variable.
> And you'd want sub-tick (frame) resolution in an app like Ardour.

MIDI clock, which is what you're syncing to, is fixed at 24 msgs per
quarter note, so there is no difference there. Ardour syncing to this
is no different than MusE.

> I want to get our MTC code working. I've got the rate
>  detectors working and have monitored input from Ardour Ok.
>
> Question: Ardour supports many different timecode fps
>  but MTC only has two bits for the fps.
> How are these other fps supported? Not for MTC

MTC only supports these rates:

  enum MTC_FPS {
	    MTC_24_FPS = 0,
	    MTC_25_FPS = 1,
	    MTC_30_FPS_DROP = 2,
	    MTC_30_FPS = 3
    };

the pull up/pull down "rates" are not really rates at all - just rules
about computing time.

MTC can be hard to sync to because the MTC transmitter can be bursty.
Torben Hohn recently applied some relatively sophisticated control
theory to the problem (in ardour3) which we believe should optimize
things but we haven't had a chance to really test it in depth yet.

--p