View Full Version : Audio out of sync with video

Bob A
08-20-2004, 01:53 PM
I have been digitizing wedding video from my Canon XL1 camera via firewire to my VT3. It creates the AVI file. The file is approximately 1 hour long. It seems the audio is gradually getting out of sync with the video. By the end of the video the clip is not useable. What is happening to cause this and how can I fix it?

08-20-2004, 02:02 PM
Try switching the type of DV capture from type 2 to 1 or vice versa depending on which you are using.
The default setting is in the preference.

Eugene? Anybody? Correct?

Bob A
08-20-2004, 04:53 PM
How do you change to DV capture to type 2?

08-20-2004, 05:09 PM
In the preference settings first setting under recording,

08-20-2004, 10:36 PM
Unfortunately, many of us have hit A/V sync issues with Type-2 DV, only if captured in the VT[3]. I can't recommend using the VT[3] to capture Type-2 DV.

Instead, set your global preference to Type-1 DV. This will let the VT[3] capture it in sync, just don't plan on using the file in other programs, since most other programs can't use Type-1 DV.

Luckily, you can render out Type-2 DV or use Type-2 DV captured in ANY program other than the VT[3] in VT-Edit and it will work fine.

This Type-2 DV A/V sync problem has been there a long time, but unfortunately I don't see it getting fixed. None of the information I and others have provided Newtek on this bug has enabled them to reproduce the problem. And since Newtek can't reproduce the problem, the problem isn't going to be fixed. :(

It's really a shame since no other programs I know have any problems with Type-2 DV, which is the universal way to do it. And for processing audio and compositing video and such in other programs, this type of compatibility is IMPORTANT.

08-21-2004, 08:43 AM

I have found that a/v will also be out of sync if you press record on the VT3 "BEFORE" you press play on the playback deck regardless of the capture format.

Make sure the playback deck is playing before you press the record button on the VT3.

08-21-2004, 06:03 PM
You might have a clearer recall of this issue than I do...
when I first got my XL1s I seem to remember reading about the audio gradually getting out of sync being a problem in general with the XL1 cameras.
And it was supposed to have been fixed in the later XL1s cameras so I never looked into it any further than that.
Does that ring a bell, or was that somehow related to the Type-2 issue you mentioned?

08-21-2004, 07:01 PM
There was (is?) a problem with Canon camcorders playing DV at 29.96fps instead of 29.97fps.

The A/V sync of Type-2 DV problem happens with any source. My sources are all Sony DV and DVCAM, for instance.

Bob A
08-21-2004, 07:23 PM
I changed the DV audio to type 1 and tried a short clip. The audio was in sync with the video. So it appears to be ok. Does the length of the clip have anything to do with audio getting out of sync? Also, will this setting effect rendering the project to MPEG2 via Tmpeg?

Thanks for all your help. :)

Bob A
08-21-2004, 07:25 PM
Oh, one other thing...can you tell me more about this audio sync problem with the SL1 camera?

08-21-2004, 10:08 PM
Type-1 will stay in sync for any length clip.

No, this setting won't affect using the VT-Edit project in TMPGEnc at all. One of the really good features of the TMPGEnc plug-in for VT-Edit projects is that it doesn't matter what mix of formats of video clips you use in a VT-Edit project, it will all look the same to TMPGEnc due to the plug-in.

I don't really know anything more about the Canon DV playback issue, just that it was something to do with the 29.96 versus 29.97 fps issue that I mentioned. Someone else may have the details on it, and which models it affects.

08-22-2004, 01:01 AM
I found a discussion of the XL1 29.96 issue, that solved the problem with Vegas Video.

I've never had the sync problem with the XL1s so I never bothered to look, but sure enough,
there in Vegas Video Capture XPress, under -options- -preferences- -capture tab-, you can set a custom frame rate.

The XL1 users in the discussion just entered a custom rate of 29.96 and everything was back in sync.

The trade-off is, over 60 minutes Vegas will drop 26 to 28 frames.

No one who used it seemed very concerened about that... it's a second over an hour.

I don't use Premiere Pro, so I don't know if it's possible to set custom rates in it.

08-30-2004, 01:20 PM
I ran into a sync problem on my last show, it was due to a camera that recorded the sound in 32k and not 48k. That threw the sync off gradually.

Might be something to look into.

Bob A
09-07-2004, 07:18 PM
Hello Paul and others,
I just digitzed a 1 hour and 10 minute piece of video shot on my XL1 via the firewire. I changed the preference to DV video type 1 (as Paul suggested). I am still getting the audio sync problem. The audio gradually trails the video as the video goes on. It is totally out of sync by the end and the project is unusable. I have had the VT3 about a year now and did most of my early work digitizing to rtv. I am now using the firewire to save hard drive space to work on several projects at once. I have probably completed one or two jobs with the firewire digitized video and am now just seeing this problem. I don't think it is a problem with the XL1 since thhe video out of the XL1 is OK. What else can be the problem? Could it be in the firewire cable? Should I reset the VT3 to default set-up. I'm really struggling here.

09-08-2004, 01:46 AM
The sync problem with the XL1 is well known and has
been established for quite some time. It carried over
to a few of the early XL1s' as well. As far as I know it
affects all XL1 cameras. I recall seeing something
about the audio theory that claimed the sync problem
was caused by Canon's early un-locked audio sampling
technique. But if that were true then the sync problem
would occur in both directions instead of just falling
behind the video.
The only solution I've ever seen is using an editor
that has adjustable frame rates.

Bob A
09-08-2004, 08:06 AM
I was thinking about digitizing the video via s-video and as a DV file at the capture window. Since this is the way to capture an rtv file do you think this may work? Will the vt3 compress it into a dv file or avi?

09-08-2004, 09:35 AM
I have a question. Could you not put sync markers at the beginning and the end of the Video and Audio clips then Stretch the Audio clip to line up?

Just curious if this would work for those that already have the problem footage in their systems.

Bob A
09-08-2004, 05:57 PM
:) Hi all,
I just digitized the 1 1/2 hour video via s-video and chose DV type 1 as the format. This fixed the audio sync problem. Also, I noticed when I dragged the s-video digitized video into TED the file loaded instantly. When I would drag a firewire digitized video into TED it would take up to 3 minutes to load. Why is this? The video quality of the s-video digitized clip is as good or better. The audio is better with no sync problems and less distortion.

09-08-2004, 08:14 PM
As some of us have stated earlier in the thread, if you used Type-1 for your firewire capture, and you still had A/V sync problems, I'd blame the non-standard timing of Canon camcorders, period.

Firewire transfer of DV video/audio, working properly, is the best quality you can get from DV. It's simply a bit by bit clone, so it's not possible for S-video to look better. But again, your firewire transfer hasn't been working well.

As for dragging the DV video into VT-Edit taking three minutes, that is because of the way VT-Edit has to generate a waveform graph of the audio track. This takes time. Typically for me, on my very fast system, it's about one minute per 10 minutes of video. While RTV clips have separate WAV audio, and the waveform graph of the audio can be generated in the background while you are capturing.