MIDI clock getting out of sync

fongaboo wrote on 6/1/2004, 5:54 AM

I am using Vegas 4 on a PIII 1ghz. I set it up to send MIDI clock to control a Roland JX keyboard. I set the BPM to 119.88 (because this works out to be 15 frames per beat with a frame rate of 29.97). I set this BPM because of concerns with another live video sequencing app that I plan to transpose my project to when I'm done.

As I built my piece, I would mostly work in 16 measure chunks at a time, and the keyboard seemed to stay in sync. But when I was done with the whole piece and played it from start to finish, the keyboard slowly got out of sync. I even shut off my video bus to see if the computer was lagging from having to draw video, but still it eventutally got out of sync (over the course of 2-4 minutes)

Any idea why? Is Vegas, the keyboard or my MIDI port to blame? I am using a SoundBlaster Live! with a front port that has MIDI In/Out.

Comments

Spot|DSE wrote on 6/1/2004, 8:21 AM

you using drop frames or non-drop? Shouldn't matter, unless you composed each section, and now are stitching them together.

DD12 wrote on 6/29/2004, 9:04 AM

Did you get this solved? I am experiencing similar issues with v4 build 239.

When I set the ruler to MidiBBClk, I also cannot persuade Vegas to add events on ruler markings, it gets further and further late as it goes across the screen. Just try dropping a hihat sample on every 1/4note and you'll see this. Mine is upto 3 pixels out by time you get to the RHS of the screen if you rely on snapping. Can't see any kind of quantize function either - guess snapping is it!!

I would dearly love to be able to delay SPP 1:1:000 to some positive SMPTE value like 00:00:04:00:00 too, but have yet to find a way to do this. Better still to consider a "region" of SPP on a track such that you could embed Midi SELECT, START, STOP, LOCATE and TEMPO commands.

Perhaps MMC could be added to the transport icons, or to the command events that can be dropped into a track?

One effect of no delay in SPP is to lose the sync of the first bar if Vegas is clocked externally. My kbd sequencer actually kicks in 2beats late as a result - perfectly in time but very late. I found I can massage the effect by playing with buffer size, but it's the wrong solution to the problem.

If I run a trace on the port, SPP is generated long before MTC kicks in too.

Will test further.

DD

DD12 wrote on 6/30/2004, 9:00 AM

Solved the markings getting out of time - my fault - I had snap to frame still switched on...
oops.

I'm going to upgrade the drivers for all attached devices as the next logical step. Seems I may have an older or mixed driver set still. Either ways about as long as I don't use both interfaces at once it seems to work most of the time, provided the buffers in Vegas are stretched out to 1second.

DD.