AVI to DVD: help with audio sync problems

[tanglemac76]

I've done a lot of searching on the forum, but I haven't found anything that helps me solve this problem.

I have an .avi of a tv show that I downloaded because when the episode aired locally a couple weeks ago it was interrupted by weather reports about tornados. I have tried many different settings and combinations to burn this episode to a DVD to watch on my television. I've tried ffmpegX (using both mpeg2enc and ffmpeg) and Toast 7. For audio options in ffmpegX, I've tried both AC3 (5.1 and stereo), mp2, and passthrough. This AVI plays fine in VLC and Quicktime. I did notice, using Quicktime, that the audio track was slightly shorter than the video track (even though I don't notice problems when playing the avi). So, I tried extracting the audio track using Quicktime Pro, deleting the audio track from the original file, and re-adding it from the extracted copy using the "Add to Selection and Scale" option. This resulted in the audio and video tracks being the same length, and the resulting saved .mov file played fine in Quicktime and VLC. But, as soon as I made a DVD or Video TS folder with either ffmpegX or Toast, the same audio sync problems were back. It seems like the audio track is almost a half of a second ahead of the video track. It is like that from the very beginning of the file. I haven't watched the file enough to see if it gets worse over time. I've also tried running the .avi through DivX Doctor, but that resulted in sync problems too.

Here is the info that ffmpegX reports about the file:
mpeg4, yuv420p, 624x352

Quicktime reports:
Video track 42:18:28 Generic MPEG-4
Audio track 42:18:26 MPEG Layer 3

Is converting an AVI to DVD without audio issues even possible? If so, what procedures have you followed to make it work for you? I really appreciate any help you might be able to offer.

Thanks!

[vix]

I'm no pro, but divx doctor has solved a few audio sync problems i've had in the past. Don't know if that will apply to your file though

http://www.3ivx.com/divxdoctor/

[tanglemac76]

Thanks for the suggestion, but I've tried Divx Doctor. It resulted in files that had audio sync problems before I even tried converting them to DVD.

[TugBoat]

The easiest way to correct it is trial and error with QT Pros editing feature. Apparently that particular AVI was muxed with delay settings that don't get exported correctly when converting to separate tracks. Another possible cause is the Scale function you mentioned or Variable Bitrate Audio. You should never scale a track that is going to be separated from the track it's scaled to. And never use Variable Bitrate Audio in a movie.

Begin as you did before on a copy of the AVI. Open in QT, select 'Show Movie Info' and 'Show Movie Properties'. Extract the Audio track, then delete the Audio track from the movie. Then convert the Audio track to AIFF (for Toast) or WAV (for ffmpegX), this will correct the variable bitrate errors. Next do a select all and copy on the Audio track and then Add it to the video track. DO NOT SCALE. Scan the new movie and see how it is synced. If the Audio track is ahead, you need to either add content to the beginning of the audio track or delete content from the beginning of the Video track. You can undo the 'Add to Movie', make the corrections, then 'Add to Movie' again. You can make the small selections with the triangles on the bottom of the QT timeline using the left and right arrow keys. The 'Show Movie Info' window will display the length of the selections as you use the arrow keys.

Once you have the beginning synced, check out the end. If the end is out of sync, then you need to use something like Final Cut Express, FCP, or some other App to 'Change the Duration' of the Audio track to match the duration of the Video track.

Yes, it's a pain. Yes, whoever made that AVI screwed it up. No, all AVIs do not have this problem.
Have fun 8)

[tgpo]

If Quicktime opens the file I would assume that QT Mutator will open the file and allow for sync issue to be addressed. At the worst you may need to convert the file to a .mov Quicktime file, but it's better than having to buy expensive editing software.

[fibert11]

Once you have the beginning synced, check out the end. If the end is out of sync, then you need to use something like Final Cut Express, FCP, or some other App to 'Change the Duration' of the Audio track to match the duration of the Video track.

Yes, it's a pain. Yes, whoever made that AVI screwed it up. No, all AVIs do not have this problem.
Have fun 8)

This is what I had to do. The audio was still a little out of sync, but it wasn't measured in seconds at least!

[tanglemac76]

Thanks for the replies. I tried the suggestion of converting the audio track to WAV for using in ffmpegx. After doing that, and selectively trimming a fraction of a second off the beginning of the video track, I was able to get the sync looking pretty good in Quicktime. After using ffmpegx to convert to video_ts, it still had a little sync issue, but not nearly as bad as before.

[TugBoat]

That's why it's called trial and error. It usually takes a few tries to nail it. And to 'do it right', you need to adjust the audio to the m2v track that's exported from ffmpegX, not the Quicktime video that's fed to ffmpegX. I use DVD Studio Pro so it's easy to import the m2v track then adjust the audio track. I guess you could do the same with QT Pro if you have the QuickTimeMPEG2.component installed.

After you get the darn things synced, use the Tools section in ffmpegX to 'Mux as DVD' and 'Author as DVD'. It is doable, but it does take time and effort. Might be easier just to download a different file that's not bonkered from the get go 8)

Or just buy a DviX Player, but, I've had to play around with about 10-20% of the AVIs I feed the DviX player too

[bobzone]

thank you gentlemen, but I still have a lot of dvd's that are unwatchable.

[tgpo]

Geez man. It may have something to do with the fact you're reading and potentially following steps that were given in 2006.