DP audio and video out of sync using MTC to slave DP

[magnumpraw]

Hey all.

Dunno if anyone has any experience with this, but I am trying to slave DP 8.03 on a mac to Cubase running on a PC using MTC via MIDIOverLAN. I can successfully get DP to lock to Cubase and the timecode on printed on the video as well as DP's timecode counter always seem frame locked to Cubase's timecode display. I can also locate around my session in Cubase and DP will jump to the appropriate timecode.

However when I start playback most of the time, the movie's audio is out of sync with the picture (early).

When I start the transport in Cubase, DP instantly jumps a second or 2 ahead pauses and then waits till Cubase gets there to start playback of the video. The audio, however starts right as hit play in Cubase and so picture and audio in DP are not playing back in sync.

Sometimes DP doesn't jump ahead and wait. If this happens then audio and video play back fine. It's not very often though.

Any ideas?

[MIDI Life Crisis]

Hmmm... intermittent problems can be hard to diagnose.

Check out page 24 of the Getting Started Guide "CONTROLLING MONITORING LATENCY"

I'd also look into pre-fill buffers SETUP/Configure Audio Settings/Configure Studio Settings.

[magnumpraw]

Thanks for the ideas

I tried setting the audio buffer in DP low (128) and high (1024). I've also tried turning on and off "pre-fill" buffers as well as trying different values. Same issue. getting me stumped.

[MIDI Life Crisis]

Is there any difference in when it happens in terms of how you;re working (recording v. playing back?)

Just a shot in the dark here, but are there and VIs and are the set to realtime or pre-render? Something is obviously causing DP to hesitate somewhere.

[magnumpraw]

The slave DP session has literally nothing in it except for an audio track with the movie audio. I'm using it only for movie playback. I have both pre-render settings in the preferences set to "plugins in real-time"

I've tried this now using both Cubase and a separate copy of DP as MTC master on a different machine with the same results.

The slave DP machine is almost always playing the audio ahead of the movie (though not always the same amount ahead).

Here's the really weird thing though. I imported the audio from the movie into the slave DP session and set the actual movie audio output to "none". When I playback the slave DP by itself, audio and video are perfectly in sync. When I slave it to the MTC master, though the audio again plays ahead of the movie.

BUT the visual waveform is perfectly in sync with the picture as the wiper moves across it. Meaning the waveform in the audio track as the wiper moves across it is spot on with the video as it plays. But what I'm hearing is ahead of both the video AND the waveform.

I've tried the slave DP setup now on a mac mini with DP 8.03, once with a MOTU 828mk2 and once with a MOTU 896mk3. I've also tried the slave on a Mac Pro laptop with DP 7.24 using the built in audio. Same results.

pulling my hair out, lol

[MIDI Life Crisis]

One more idea before I head out to see the new Star Trek movie...

Maybe re-export the movie from Quicktime Pro to a smaller size? I can't think of anything else at the moment - except dinner...

[magnumpraw]

Star Trek movie rules.

Thanks for all the suggestions. Movie is already pretty small and plays completely fine if DP isn't set to external sync.

Have fun!

[MIDI Life Crisis]

I will. It's screening at the Academy of Motion Picts with a discussion following with the composer.