OT: DVD audio loses sync during film festival

Just got back from the Cleveland International Film Festival where my short film "SHADOW.NET" screened. The fest was really great but my screening just about gave me a heart attack. I found out after I got there that my Digibeta had overmodulated audio (dubbed it too hot, my bad) so they had to screen it off a DVD. The short is 20 minutes, and it played fine up until the last two minutes when the audio ended up out of sync by at least a second. I don't think a lot of people noticed, but it was excruciating for me.

I've double-checked my DVDSPro project and another copy of the DVD that was duplicated in the same batch: everything is in synch. We watched another feature there that was at least a half second out of sync all the way through (or perhaps the worst ADR job I've ever heard) so I think the issue was with their equipment. But what would have caused this, especially the audio starting out fine but then drifting out of sync over time? Have any of you seen this before?

JK

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SCQT! Self-contained QuickTime ? pass it on!

I remember at least two of my older DVD players that would have this issue. And I was quite certain that it was just plain old inability to maintain the data rate. I used to pause or stop the DVD and immediately restart it, and that would fix the problem.

Doesn't help you in your situation, unfortunately. That's why I never use DVDs for screenings if I can help it. The faulty DigiBeta output really screwed you there. Didn't you guys use reference tones?


www.derekmok.com

yeah- DVD for screening sucks. Also DV for screening can go glitchy at the exact wrong minute. Digibeta cannot be beat for playback reliability. But make sure to QC.

-Noah

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Mac DVD burners are really bad. I've had four and none of those was able to make a decent DVD. Got this confirmed by replication house: they were totally unable to use my DVDs as masters because of data corruption. Your Mac can probably handle a self-burned DVD with it's advanced error correction but older set-top players can't. Cascading errors on the disc overwhelm the circuits and you're out of sync. Throw in a professionally mastered commercial DVD and problems magically disappear.

They are selling those cheap video cameras with HD out for $600. How about using one of those as a backup player??

I don't think Mac DVD burners are the problem...the sync issues I've had have been with major commercial DVDs (eg. House, M.D. Season 1, Spider-Man), not burned video DVDs.

Older DVD players -- and let's also not forget those no-name brand players -- are basically doomed to "take it or leave it". Can't rely on them.


www.derekmok.com

Thanks for the clarification guys. I didn't recognize the DVD player brand so it was probably a data rate issue as Derek suggests. It's just so frustrating not being able to make a disc that is compatible with even 99% of the players out there. But that's DVD for you I guess.

The Digibeta audio sounded fine on our end but levels were still too hot for their mixer, and I didn't want to take any chances. Lesson learned

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SCQT! Self-contained QuickTime ? pass it on!

> The Digibeta audio sounded fine on our end but levels were still too hot for their mixer

That shouldn't be. Did you mix to -20dB or -12dB?
You shouldn't be using your ears as the only gauge. If your own deck was set too low, you could be misled into thinking your levels are fine even though they're in the red.

> It's just so frustrating not being able to make a disc that is compatible with even 99% of the
> players out there.

No one can. Non-commercial DVDs have a success rate closer to 86 to 92 per cent, higher for DVD-Rs than DVD+Rs.


www.derekmok.com

One final comment about the Digibeta:

I just went back to the post house I used to make the dubs and we re-checked everything. While the original tape (an HDCAM master) was loud, up to -4db in parts, it never peaked out. We listened to it in two different rooms and sets of speakers, sounded just fine. We had laid down ref tone at -20.

I re-recorded it (and made another Digibeta) with lowered levels so that there's a little more head room. But it seems to me that the equipment at the festival may have been at fault; I watched the meters on their machine and the tape played back way too hot. Wonder if they didn't bother to calibrate it to the ref tone...

JK

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SCQT! Self-contained QuickTime ? pass it on!

They shouldn't need to calibrate to reference if they'd left the deck in unity. Did they have to do setup on a Beta tape that ran previous to your tape, or something? The audio pots on the front of the deck should have been pushed in, and the slider for video calibration should be in the center position. (On Sony and Thomson decks)

A properly mastered DigiBeta, played back in a DigiBeta deck in unity, should not require any calibration.

If you ever find yourself in this same situation, ask them if the deck's manual setup has been turned on. It shouldn't be for most DigiBeta tapes.

debe