[LAU] MIDI clock & sync

Paul Davis paul at linuxaudiosystems.com
Sat Aug 1 18:05:45 EDT 2009


On Sat, Aug 1, 2009 at 8:01 AM, Julien Claassen<julien at c-lab.de> wrote:
> Hi Robin!
>   I always thought, if you have MIDI clock data, you can send it via a MIDI
> port. So the MIDI clock is the source of timing for MIDI gear. Am I completely
> of the mark here?
>   If I have a MIDI clock synced to JACK transport I shouldn't have drifts if I
> somehow get it to my sequencer. Or what? I'm confused now. :-)

MIDI Clock provides information about position along a timeline
measured in musical time (beats & bars).
MIDI TimeCode provides information about position along a timeline
measured in hr:min:sec:frames (frames == video frames)

They are not at related to each other in any way (other than both
using MIDI to transmit positional information).

Further, MIDI Clock is theoretically useless unless the receiver knows
the tempo/meter map. In practice, many common pieces are in a single
tempo and meter, and you simply set the receiver to match the sender.
the MIDI Clock data stream contains no information about the
tempo/meter map that it is derived from.



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