MiniDV to DivX/XviD (w/ AutoGK): audio out of synch due to dropped frames??

[alexon]

Hello,

I recently started recording a TV series with my Sony TRV-60 camcorder onto MiniDV tapes and I want to convert said episodes to DivX or XviD files.

So far, I’ve used Auto Gordian Knot (AutoGK) 2.55 and everything works OK, EXCEPT for the fact that, in the resulting DivX/XviD files, the video and audio start in synch and become more and more out of synch as the episode progresses.

What I do:
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1) Record each episode using my TRV60 camcorder (which has an analog to digital conversion) onto DV tapes.

2) Capture the resulting AVI file to my PC. I do this using either WinDV or Sony Vegas 6.0. Both programs work, but both report around 50 dropped frames per 30 minute episode (don’t know whether that’s relevant to the synch problem, but it’s not noticeable when watching the resulting AVI file).

3) Use AutoGK 2.55 (which installs VirtualDubMod, AviSynth, and an XviD codec, as you know) to convert the huge AVI files captured from the DV tape (about 6GB for a 30 minute episode) to a 300MB DivX / XVid file.

The problem:
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The resulting XviD file (created with the codec provided by AutoGK) or DivX file (using DivX codecs downloaded from the net: 5.2.1, 6.0, 6.2 or 6.5) has an audio/video synchronization problem.

In both XviD and DivX, the audio and video start in synch and gradually grow apart. At the end of the episode, the audio is about 2 seconds slower than the video.

What I’ve tried:
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1) Different DivX codecs, as stated above (by the way, of these, only DivX 5.2.1 works with VirtualDubMod; the others give an “error code -2: the source image format is not acceptable”). Both Xvid and DivX files display exactly the same synch problem.

2) The solution proposed in the AutoGK FAQ (“Load the file into VirtualDubMod. Set BOTH ‘Video’ and ‘Audio’ >’Streams’>’Stream list’ to ‘Direct Stream Copy’. From under the ‘Video’ dropdown menu, select ‘Frame rate’ - and select ‘Change so video and audio durations match’. Save with a new filename.”)

Well, when I load my DivX or XviD file in VirtualDubMod, I get the error “VirtualDub has detected an improper VBR audio encoding […] Do you want to rewrite the header using standard CBR values?”. First of all, I don’t understand the error, since it was VirtualDub itself that handled the AVI -> DivX/XviD conversion in the first place!! In any case, regardless of whether I accept the header rewrite or not, the advice given in the FAQ fails. The resulting file is still out of synch.

My questions (finally!):
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1) Could the synch problem be due to the dropped frames during the DV capture? It would make sense, since the missing frames occur more or less evenly and the 50 missing frames (my DV is PAL) would eventually add up to roughly 2 seconds. If this is the problem, what’s causing the dropped frames and how do I fix it (in WinDV or Vegas 6)?

2) If the dropped frames are not the issue, is there another SIMPLE solution to this synch problem using AutoGK? I’m a complete newbie, so suggesting “remuxing”, “recoding” (etc) the out-of-synch DivX files using yet another set of programs would really throw me off

3) Is there another tool to convert DV-captured AVI files to DivX (or XviD) with less effort and more success? I will have over 40 episodes to convert and I’m already at the end of my rope on episode 3.

THANKS A LOT FOR READING THIS FAR

Anxiously awaiting your kind help,

Alex

[Gavino]

Could the synch problem be due to the dropped frames during the DV capture? It would make sense, since the missing frames occur more or less evenly and the 50 missing frames (my DV is PAL) would eventually add up to roughly 2 seconds. If this is the problem, what’s causing the dropped frames and how do I fix it (in WinDV or Vegas 6)?

This seems the most likely explanation.
The key question is - does the original DV avi play in sync?
What are its video and audio durations reported by GSpot or MediaInfo?

If you do a forum search, you will find plenty of advice about avoiding dropped frames, eg
https://forum.videohelp.com/topic157660.html.

[alexon]

Hello Gavino,

Thanks a lot for your reply.

The original AVI file is perfectly synchronized all the way through, that's why I thought that the synch problem wasn't due to the dropped frames.

I don't have GSpot or media Info here, does VirtualDubMod provide the information you mention?

Thanks for the link.

Best wishes,

Alex

[Gavino]

I don't have GSpot or media Info here, does VirtualDubMod provide the information you mention?

Yes, under "File information".
I still recommend installing those tools, which I find invaluable, especially for diagnosing problems.

[alexon]

This is the file information of my out-of-synch XviD according to VirtualDubMod.

Can you tell what the problem is?

Thanks again,

Alex

[/img]

[Gavino]

The video and audio durations appear to match (within 0.02 secs). It would be interesting to know if the same applies to your original DV avi file.

However, I suspect the problem might be that the XviD video has VBR (rather than CBR) MP3 audio, which often causes problems. How did you specify the audio conversion when you created the file in VDubMod?

[alexon]

Yesterday I captured the AVI file again from the DV tape following the advice from the link you posted and VOILA! It worked. I stopped my antivirus and captured to a different disk drive. As I result, I got 0 dropped frames and, lo and behold, no more video/audio synch problem when converting to DivX.

The only (small) remaining problem is that Vegas created two avi files and I don’t know how to merge them into a single DivX with AutoGK (apparently the merge option only works for VOB files). But I’m sure there’s a ton of programs to do this, so I’m not worried.

Thank you very much for your help

Alex