Audio/video sync issue in Premiere

[ksproul]

I did a lot of reading about similar problems before posting this, but didn't see any that were exactly the same as mine, at least not with a working solution, so I thought I'd try posting here.

I captured an 85-minute DV video in Adobe Premiere Pro 1.5 via firewire from my Sony DCR-TRV730 camcorder (Digital8). The video captured just fine, and when I play the AVI back in a program such as Media Player or VLC, it plays fine, with audio and video 100% in sync throughout. The problem comes when I take that same AVI and put it on a timeline in Premiere. When I do that, the audio and video are out of sync (video trails the audio by maybe half a second) by the end of the video. They start out in sync, but slowly drift as the video goes on. It does not correct the problem if I stop and start playing it in the middle. I can start right near the end, and it will be out of sync as soon as I hit play. This is without any editing whatsoever, and it affects both previewing in Premiere and exporting the movie (same sync issue either way).

I've read some possible workarounds to problems like this, but I'm more interested in correcting the problem than working around it. Any ideas on what could be causing this and/or how I can fix it?

Thanks,
Kris

[ksproul]

I've done some further investigation on this and may have found the culprit. I noticed that the framerate of the captured AVI file is either 29.972 (according to GSpot) or 29.971 (according to VirtualDub). Since Premiere seemingly will only play it back at exactly 29.970 fps, it makes sense that the video would be lagging behind the audio slightly, especially after 85 minutes. Why it works fine in other programs, I don't know. Maybe the other programs play it back at the actual framerate, rather than the set 29.970. Anyway, I haven't found a way to fix this in Premiere yet. Adjusting the framerate in another program doesn't seem to help, since Premiere is still going to play it back at 29.970 regardless.

As another attempt, I tried capturing the video using WinDV, rather than Premiere. When capturing a type 2 DV file, I actually run into the sync problem outside of Premiere as well, meaning the WinDV-captured file has the same sync problem when played back in WMP, VLC, etc. I'm not sure why this is. So I tried capturing a type 1 file in WinDV, just to see what would happen. The file is perfectly in sync when played back with WMP, VLC, etc. I also tried opening this file in Adobe Encore DVD (which had experienced the same sync problem as Premiere did with the original file), and this time it had no sync problem. So I tried bringing the file into Premiere, expecting it would solve my problem. However, Premiere sits there generating the peak file, then freezes when it hits 100%. It only does this with the type 1 file. I thought Premiere Pro was supposed to support these files. Before running the full video in, I had even captured a shorter type 1 file in WinDV and imported it into Premiere with no problems. It's just the full 85-minute type 1 file that Premiere won't finish opening.

So that's where this stands right now. I'd love to get this working either using the type 2 or type 1 file. I'm convinved that the type 1 file will solve the problem if I can just get Premiere to finish opening it.

I'm also aware that I could solve the sync problem by changing the duration of the audio, but I shouldn't have to do that, and I'm more interested in getting it in sync in its unaltered state.

Any ideas? Any help would be greatly appreciated!

Thanks,
Kris

[Megahurts]

To verify it's not a framerate problem, open the file with VirtualDub. Check file information and see if the length of audio and video are the same.

The lengths are displayed down to .01 of a second.

[ksproul]

Thanks for the suggestion. I checked out the original type 2 file in VirtualDub. Here's what it reports:

VIDEO:
Frame rate: 29.971 fps
Length: 155498 frames (1:26:28.23)

AUDIO:
Sample rate: 48000 Hz
Length: 249043877 samples (1:26:28.41)

So the video is showing up as slightly shorter than the audio. Any suggestions?

I also checked the same for the type 1 file in VirtualDub, and the audio and video lengths match perfectly, as expected. If I only I could get that file to finish opening in Premiere. I'm thinking I could probably convert this type 1 file to a type 2 file, then open it in Premiere, but I don't want to have to do that every time I work on something like this. I'd still rather solve the problem than work around it.

Thanks!

[Megahurts]

I don't have Adobe Premeier Pro but do have Adobe Premeire 6.5 and I'm able to right click on the video timeline and select Duration. If you can do this, enter the time that VirtualDub reports as the audio length.

You mentioned that you changed the framerate. What program did you use and were the results exactly the same?

[ksproul]

The speed/duration change could work, but I'd rather not do it that way. I'm not sure exactly how that function works in Premiere, but it seems that it's not a simple adjustment of the playback rate, but rather a destructive edit of the video. I tried changing it, but it required the whole video to need to be rendered to view the change, so it seems that this method would actually change the content, if I'm understanding this correctly. Additionally, Premiere is reporting the length of both the audio and video to be 1:26:28:14 (I believe the end is in frames here, so that works out to 1:26:28.47) before I change anything, which is different from the times VirtualDub is reporting. When zooming in at the end of the file, you can clearly see that the audio ends before the video though, just with blank space filling up where the audio should be for the last 9 frames of video.

As for changing the frame rate, I tried changing it from 29.971 to 29.970 in VirtualDub, but if I remember correctly (I've tried so many things since then), the result the same in Premiere and worse in WMP and VLC, as now those were playing it out of sync as well.

On another note, just to rule out any computer issues (and because it had been a while anyway), I did a complete format of my C drive and reinstall of Windows XP SP2 and all my programs this weekend. It made no difference with this problem, but at least I've got a completely clean OS now. I even tried recapturing the entire video last night, just in case, but had the same results. This is driving me nuts!!!

[pijetro]

Just a shot in the dark here...

1. Are you running your camcorder off a power supply, or a battery?
2. Are you using the standard NTSC DV 48khz settings?? If so, do you have drop frame timecode enabled on capture, or on your general settings?
3. Would you know if the original audio was recorded in 16bit or 12bit on tape?

[alegator]

Ksproul, I run into the same issue. Check my thread:
https://forum.videohelp.com/viewtopic.php?t=307841

[garringt]

I use Premiere 6.5 and occassionally have an issue of losing A/V sync on long videos when playing the video from the timeline. However, after I render the video, everything is back in proper order.

It seems the longer I'm in a Premiere session, the worse it gets. When it become really distracting, I save my project, exit, and start Premiere again. Then everything is back where it's supposed to be for a while.

This loss of sync doesn't happen everytime I edit, and usually only on videos over 20 or 30 minutes (most of what I do is less than 10 minutes).

[ksproul]

Thanks for the replies, everyone. I'll try to answer all of the above questions/points:

I'm running the camcorder off the AC power supply. I haven't tried doing the transfer with it running on battery power. Is there any reason why I should?

Yes, I'm using all the standard NTSC DV settings (48kHz audio, 30fps drop-frame timecode, etc.) for the project and capture.

The original audio is 16-bit. I've never used the 12-bit mode, as I have no use for it.

As for rendering the video, I'm having the problem before I made ANY changes whatsoever, so there's nothing to render. I tried to "Render Work Area," but it doesn't do anything, as nothing has changed and there is no red line above anything. Also, the results are the same whether I'm previewing from the timeline or exporting the video. Additionally, I noticed that the sync issue is present even if I simply drag the AVI file into the source window to preview it. It's still out of sync, before I even get it on the timeline, so I don't think setting in/out points there, as alegator said somewhat worked, would help. I should also note that I'm not doing any cutting or splicing at all here....it's out of sync right from the start, but only in Premiere.

[pijetro]

I'm running the camcorder off the AC power supply

Yes, this is what i was going for...Batteries potentially fluctuate in power..

Yes, I'm using all the standard NTSC DV settings (48kHz audio, 30fps drop-frame timecode, etc.)

I hope you meant 29.97fps drop-frame.

Within the "Capture" window, you can dig a bit deeper, and find a list of capture devices..
Are you using a generic capture device, or is it camcorder specific?

What's even more ironic, is the fact that there's no red line above the clip..This would indicate that you're within project setting limits, yet, it's enough to pass by..
I'll assume that you don't have the luxury of borrowing somebody elses D8 to verify...

Earlier stated:

I tried changing it, but it required the whole video to need to be rendered to view the change, so it seems that this method would actually change the content, if I'm understanding this correctly.

As much as i agree with you about not having to stretch anything, it really isn't a big deal to simply stretch the audio to match the video...(not the other way around).
Zoom in tightly on the end of the clip, press "X" (speed change), then click "ALT", and slide back only the audio to snap with the video ending. The sample rate will change, but will most likely be insignificant...

[ksproul]

I hope you meant 29.97fps drop-frame.

What I meant was the display format is set to "30 fps drop-frame timecode" (29.97 isn't an option in that particular dropdown menu). Of course the timebase is set to 29.97 fps.

Within the "Capture" window, you can dig a bit deeper, and find a list of capture devices..
Are you using a generic capture device, or is it camcorder specific?

In Premiere Pro 2.0 (I upgraded from 1.5 when I did the reinstall), the only place you can pick a list of specific devices is for the device control. In that, I picked Sony standard (my specific model isn't listed), but I believe this only affects the device control, not the capture itself. For the capture itself, the only choices are DV Capture, Adobe HD-SDI Capture, and HDV Capture. Of course, I'm using DV Capture.

What's even more ironic, is the fact that there's no red line above the clip..This would indicate that you're within project setting limits, yet, it's enough to pass by..
I'll assume that you don't have the luxury of borrowing somebody elses D8 to verify...

That thought has crossed my mind too, but I don't know anyone with another D8 I could borrow. I should also note that the D8 I'm using to transfer the video is not my original D8 I recorded it on, although it is the same exact model, the TRV730. A friend permanently borrowed my old one and ended up having to buy me another one (from eBay) when he lost track of mine.

As much as i agree with you about not having to stretch anything, it really isn't a big deal to simply stretch the audio to match the video...(not the other way around).
Zoom in tightly on the end of the clip, press "X" (speed change), then click "ALT", and slide back only the audio to snap with the video ending. The sample rate will change, but will most likely be insignificant...

Yeah, I know this isn't a problem to do, and I work with audio a lot, so I'm quite accustomed to altering the speed/duration of audio from various sources to match each other, as I'm often working with audio recorded on different DAT decks. But we're talking about audio and video that should be perfectly in sync here, and they ARE outside of Premiere. Additionally, zooming in on the end of the file at frame level in Premiere, the boxes representing the audio and video files end at exactly the same spot, but the audio box doesn't have audio all the way to the end. As stated above, the last 9 frames or so are silence. I still think it's the video that's off though, not the audio, and Premiere is just show the audio with some blank space on the end to match up with the end of the video.

To give you a bit more background on what I'm doing here, I'm actually going to be replacing the original audio from the camcorder with a DAT recording anyway, and that recording will need to be slightly altered in speed (by like 0.003%) to match the video. But that will not always be the case with things I'm transferring, and even though I might expect to need to do this when I'm replacing the audio, I should NOT have to alter anything to keep the original audio and video in sync. I know I could fix this problem easily with workaround like altering the audio, but I'm just bothered that I'm having this problem to begin with.

Thanks for all the suggestions so far!

[edDV]

What's even more ironic, is the fact that there's no red line above the clip..This would indicate that you're within project setting limits, yet, it's enough to pass by..
I'll assume that you don't have the luxury of borrowing somebody elses D8 to verify...

That thought has crossed my mind too, but I don't know anyone with another D8 I could borrow. I should also note that the D8 I'm using to transfer the video is not my original D8 I recorded it on, although it is the same exact model, the TRV730. A friend permanently borrowed my old one and ended up having to buy me another one (from eBay) when he lost track of mine.

I've been following along scratching my head wondering if I had ever seen anything like this. I record many long programs in DV format from the ADVC-100 (locked audio mode) or from a MiniDV camcorder in pass-thru mode and never noticed DV audio loose sync in Premiere or Vegas.

I have seen that different camcorders free run at slightly different speeds when editing multi-camera on the same time line but I haven't noticed audio and video from the same camera drift apart.

So, I was wondering what sounds different here. The first thing that grabbed my atttention was 85 minutes. My Digital8 is a first year model and doesn't support LP mode. It will only go 62 minutes.

Then I saw you say transfer is from a different camcorder than the one that recorded the original video. I've read of LP mode problems playing tapes from other camcorders. So, could all this be related to LP mode on Digital8?


PS: FWIW all my long captures (up to 6 hours) have used WinDV in Type 2 mode. I haven't tried doing that with the Premiere or Vegas capture programs. Also, my long captures have always had device control shut off.

[ksproul]

It was recorded in SP mode on a 90-minute tape. Sony makes 90-minute tapes (135 in LP mode) specifically for Digital8 (rather than being limited by the 60-minute limit of regular 120-min Hi8 tapes). That was part of the reason I got a D8 camcorder back in 2001, rather than a MiniDV, because I knew the longer tapes were available and one of the main things I bought it for was to video tape concerts that are often 60-90 minutes.

I've never even tried using LP mode, exactly for the reason you mention. It just doesn't sound like a wise way to record things you care about the stability of.

[edDV]

OK, I'll go back to wondering.

[ksproul]

Yeah, I'm still wondering too.

On another note, I want to thank pijetro for the instructions on how to stretch the audio visually to match the video. While it's still a workaround to the problem, this is the easiest way I've seen to "fix" it so far, and it allows frame-accurate adjustments, which is great. I think I might just use this workaround for now, but I still have more videos to transfer, so if you guys have any other suggestions, please keep them coming!