URGENT: Quicktime movie looses sync !!!

[Arno Peeters]

I know this topic was on the board before, but my search didn't find the thread...

I've imported a DC30 captured movie: PAL 384x288/1mb, conformed to 25fps (EBU) and imported the audio within PT ('Import Audio from Current Movie').
After that I deleted the audiotrack from the movie since I feel that it makes it scroll 'n scrub more smoothly (just a guess).

At the start it syncs up perfectly with the voice-tracks, but near the end (ca. 12') it lags a couple of frames behind... I thought this would only happen on much longer movies... How can this drifting happen...? What can be done about it ?
Which should I trust: audio or movie ?

Any help's much appreciated (my client comes in in a couple of hours...)



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Arno Peeters
www.tapetv.nl

[georgia]

What's the frame rate of yuor session ?
What's the frame rate of your imported Movie?
If you imported it at 25fps is that actually the frame rate or did somebody give you the wrong frame rate info ?
what's the audio sample rate ? 44.1 or 48
check to assure pulldown or pullup is not set

cheers

geo

PS: don't ya just luv the movie business

[jimlongo]

Other than the usual capture/conform/timecode things to check, I think you would be better to record the audio straight from referenced videotape. You know this is true, so if the movie can't sync to that you've narrowed down the possible problems.

good luck,

jim longo
Rhythm Division
rdiv.com

[Peter Steinbach]

It does'nt seem to be a frame rate/ pullup (down) issue. If the pullup was wrong, then the sync error would be around 18 frames (18,000 frames times .001), rather than "a couple". My partner has been having a similar problem with his fuse card. He loses sync in a manner similar to Arno. I have an identical setup, and my sync is rock solid. Nobody seems to have an answer for us, but we think it MUST be the video card.
Any other thoughts out there?

[Ashley Revell]

I have noticed this a lot with NTSC 29.97. The video is captured perfectly but there is typically half to 2 frames drift in the audio track.

This happens during capture. If you look at the tracks in the Premiere timeline window and expand so you can see the waveform you can see the drift.

Interestingly it doesn't seem to matter how long the captured video is. Be it 5 minutes or 20 minutes the drift is similar.

[RMolina]

We had the same problems 'till we downloaded and installed a new set of drivers from miro's web site. I think you guys should check there.
Just be careful, if your system is working o.k. leave it that way, because I've heard of some friends that experienced problems after the update.

[dcornutt]

I can't remember the particular forum off hand..but some people were reporting that importing audio into PT 5 does so with an "offset" of sorts.
If I remember correctly..if you look at the wave forms..you will see some extra material (of a few msecs) at the begging of your tracks. Im really vague on this cause it was a while back..it may have been in the PTle forum.

Another thing to watch for is drop frame vs non drop frame time code. Since you are working in PAL I don't know if or how this might effect you..but...anyway..just in case...

in drop frame..it drops 2 frames every min for all mins..that don't end in zero.

So, if your video was 1 min long..and you were loosing 2 frames..this would explain it.

So, check your import settings..it may be conforming somehow to drop frame and should not be.

The other thing is the "added material on import bug in PT 5.

Im sorry I don't recall the exact place on the forum where I saw this..but..if your video is more than 1 min long..and you are missing 2 frames at the end..this might be a possiblity.

Other than that..if your video was captured using a diff sample rate than the audio you "replaced " it with in PT..this could also cause some sync problems. I have experienced this before.

My chops on this are very basic..so..take with a grain of salt...but..mabey this might give you a starting point.

Hope this helps.

dfc

[Arno Peeters]

Thanks for all the replies: this is what I've found out so far: if you capture in Premiere and you have 'conform movie to xx fps' ticked in the recording options, this will NOT conform the movie in the same way the 'Conform Movie' in the tools menu does. For some of you this might be obvious, but to me this was new.

Another thing to check is to disable TC freewheel (Session setup) and I lowered the data-rate from 1000 to 800kbps. Double checked that on both instances in Premiere (4.2.1...5.1. sucks) it says the same format:PAL in my case.
You can do this in Rec. Settings/Video input/Source AND at the same time you can have another setting in Rec. Settings/compression/Options (!)
Never trust the presets completely !

With these settings changed, the new capture I did was perfect. The final thing was copied to 48kHz/24bit for mixing & mastering.

But I'm still not fully convinced. For your info: I ran a PAL capture @ 25fps in a 44.1 session and ripped the audio from the QT-movie for reference (in Premiere: 44.1/16 @ 2 sec audioblock size). The frame rate/ pull up& down in PT was not set.

Digi ? Any idea ?



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Arno Peeters
www.tapetv.nl

[StefB]

Watch out for sync on Premiere 5.1 Version 4.2.1 is better that way. I have encountered "Long" video frames at 25 fps PAL with my Fuse card, and ONLY the filemenu - tools - conform movie sorted this out. I work on 1200kb/s rate and some files run 25 odd minutes without losing sync. If Premiere did not report lost frames after capture, then the conform function will sort you out. Sometimes you will still have a "long" or "short" frame on the first frame of your movie, but moving it 2 quater frames left or right will sort that out.

[Arno Peeters]

Thanks StefB ! I've found out the exact same things. Somehow 5.1 seems to suck Big Time. Could the capture-rate be of any influence on the loss of sync ?



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Arno Peeters
www.tapetv.nl