gradual loss of video-audio sync in converted file

[captnemo]

I am having loss of sync issues converting old VHS tapes to VCD or SVCD. Here is the process I am using:

I use the pass-through capability of a Sony TRV350 camcorder to convert the VHS analog to a DV which I send to the computer via firewire and save to an AVI file with WinDV. This process works flawlessly with the exception that the resultant video does not seem to have the same level of brightness as the original video.

Next I run it through virtualdub freeze to look for broken frames - but have never had any.

Next I open the AVI in virtualdub (using panasonic DV codec) and cut out unwanted scenes, process it through the brightness filter to lighten it up if needed, then save as AVI. I then open it in virtualdub again and check it. At this point video and audio have always been in sync. I close out virtualdub. If I check it in media player it is in sync as well.

Next I open TMPGenc, and using one of the guides referenced on this forum, convert to SVCD mpeg2. When I review the resultant mpg file, I notice that the sound gradually gets out of sync towards the end of the file. It is okay until about 40 minutes into the video and then it begins to be noticable, and gets gradually worse as time goes on. I am convinced this is a gradual process and not an instantaneous loss of sync.

I went back and double-checked the avi file and it is definitely okay. I have also used virtualdub to save the audio as a wav and then recombine with the avi during the convert in TMPGenc, but there is still a lack of sync towards the end of the resultant mpg file.

I have also converted to VCD but get the same loss of sync.

I have tried to work this issue for so long and on several different video's that my trial period for the mpeg2 codec has expired. There is no sense buying the software until I get this problem solved. Since I have the same problem with VCD, I have been using it for testing.

Any suggestions?

Also is the loss of brightness normal?

Thanks.

[wwjd]

captnemo

I capture VHS quite a bit but I use an ADVC-100, your using a DV cam, which should do the same thing. I also use WinDV to get the DV data to my HD. I have been using Ulead Video Studio 8 to edit the avi file and then author. Audio sync has never been an issue. Give the trial version of US8 a try, it is fully functional during the trial period.

Is the brightness loss observed when you play your SVCD/VCD on your TV? If not, you need to be certain that the change in brightness is not due to the setting on your computer monitor. When I first started transferring VSH I ran my video through brightness and color filters only to find that the corrections I made were due to the way my monitor was setup. You need to burn the video and see what it looks like on the source that you intend to watch it on.

wwjd

[Capmaster]

Timebase corrector. Does your camcorder have one that's in-line for pass-throughs?

[rkr1958]

captnemo, I experience something similar to what you have when converting / backing up VHS Movie tapes to DVD. I use my Sony TRV-320 to pass through, convert the VHS to digital and capture it as AVI. At that point the audio is still in sync. I find however, that if I just convert it to MPEG-2 (using TMPGEnc Plus) that the audio will gradually lose sync.

Here's what I do (after capture of VHS to AVI):

(1) I strip out the audio using Goldwave and save it as a wav.
(2) I encoded the AVI using TMPGEnc Plus to MPEG-2 video (.m2v) only.
(3) I check and record the length of the video (in TMPGEnc DVD Author, which is what I use to author the DVD).
(4) I open the audio (again) in Goldwave and convert it to 48-KHz.
(5) Next, I use to the timewarp function in Goldwave to make the length of the audio the same as the video. I usually find the audio loses about 0.5 to 1.0 seconds per hour (too short) in length compared to the video.
(6) Next I check the audio and video sync in TMPGEnc DVD Author by playing a scene near the end with someone talking and facing the camera. 9 times out of 10 the audio and video are in sync and if so go to step 8 if not (1-out-of-10) go to step 7.
(7) Rare but happens ... audio and video are still out of sync ... through trial and error, vary the audio length using the time wrap function in Goldwave until and audio and video are in sync.
( 8 ) I then combine the .m2v video and 48-KHz timewarpped wav audio in TMPGEnc DVD Author and then author. I have the ac-3 plug-in for DVD Author so it converts the wav to ac3 audio.

The result, a DVD with audio and video in sync even after 2 or 3 hours.

Now, I know that the above is for authoring DVDs and that you're authoring VCDs and SVCDs but I think the above process adapted to your particular application should / will work.

By the way, Goldwave has a free trial so you could try it out and see if you can get a process that works before you buy it. Also, there might be a free alternative to Goldwave but if so, it may not be as easy to use.

Good luck.

[Almost Human]

For almost all of us that do not use an external device between the DV camcorder and our computer, gradual AVI sync loss is unavoidable. My two computers lose sync at about .2 second per hour, so at the end of a really good 2 hr movie the anticipated punch-line is really hard to watch. Nobody seems to have a definite answer to why this happens, other than say poop happens. Here is the FREE way I correct this problem:

“Capture” the movie via the pass-through function (may need to remove the tape first) with Win DV in Type 2.

Before making any changes, like cutting out unwanted sections:

Open your AVI in VirtualDub, under “File”, “File Properties”, check to see if the video and audio are the same length. If they are not the same length, then…

Under "Video" select "Frame Rate".

In "Source rate adjustment" select "Change so video and audio durations match, OK.

Under "Video" select "Direct stream copy".

Under "File" select "Save as AVI".

Save to the other hard drive.

Check your new AVI's file info and you will see that the audio and video are the same length.

Go ahead and cut the unwanted sections.

Save back to the original hard drive making sure the video "Direct stream copy is still checked", or frameserve to TMPGEnc or other.

This will probably produce an AVI with a frame rate of 29.968 or thereabouts which is still within the normal parameters of most encoding programs (TMPGEnc has no problems with it).

I also have noted an apparent loss of color saturation, but is rarely noticed when played on a TV. Two movies that did have noticeable loss were processed with a third party filter in VirtualDub – Hue/Saturation/Intensity Filter for Virtual Dub (Version 1.2). Usually a 15% - 25% increase in Saturation is sufficient.

[captnemo]

Thanks to everyone that replied.

There is no setting on my camcorder to "lock" the video and audio. I don't think that is the problem anyway since the AVI file that WinDV creates is always in sync.

Today I captured a 2 hour movie that ended up as two avi files due to the setting in WinDV. I spiced them together in VirtualDub and then did a direct stream copy back to disk. The resulting file is 26,690,718KB and the file information, when I load it back in to VirtualDub, shows the video and audio lengths agree at 2:02:16:39. Next I used TMPGenc to convert to mpeg-1 (VCD) format, but, before I started I used zone alarm to lock internet access and also shutdown the virus software. This seems to have made a big difference since it appears the resultant mpeg-1 file is in sync. I need to try this a couple times both ways to be sure this was the problem, but I appear to be making progress.

I would assume that when an AVI file is checked in Virtualdub and the file information says that the video and audio lengths are the same, then stripping out the audio and recombining it when doing the convert in TMPGenc should not be necessary. However, rkr1958 says things go out of sync during the convert even if they are in sync in the AVI file. That has been my experience as well. Does anyone know why this occurs? I note from reading the forums that a lot of people use the Canopus card with good results and an audio-video "lock" is mentioned as one of the advantages. Still, it seems to me that if things are in syc in the AVI file, then the loss of sync must be occuring during the convert and not the capture. Or am I not understanding something?



Thanks.

[captnemo]

Thanks to everyone that replied.

There is no setting on my camcorder to "lock" the video and audio. I don't think that is the problem anyway since the AVI file that WinDV creates is always in sync.

Today I captured a 2 hour movie that ended up as two avi files due to the setting in WinDV. I spiced them together in VirtualDub and then did a direct stream copy back to disk. The resulting file is 26,690,718KB and the file information, when I load it back in to VirtualDub, shows the video and audio lengths agree at 2:02:16:39. Next I used TMPGenc to convert to mpeg-1 (VCD) format, but, before I started I used zone alarm to lock internet access and also shutdown the virus software. This seems to have made a big difference since it appears the resultant mpeg-1 file is in sync. I need to try this a couple times both ways to be sure this was the problem, but I appear to be making progress.

I would assume that when an AVI file is checked in Virtualdub and the file information says that the video and audio lengths are the same, then stripping out the audio and recombining it when doing the convert in TMPGenc should not be necessary. However, rkr1958 says things go out of sync during the convert even if they are in sync in the AVI file. That has been my experience as well. Does anyone know why this occurs? I note from reading the forums that a lot of people use the Canopus card with good results and an audio-video "lock" is mentioned as one of the advantages. Still, it seems to me that if things are in syc in the AVI file, then the loss of sync must be occuring during the convert and not the capture. Or am I not understanding something?



Thanks.