[Suggestions?] Help "fixing" AVI files.

[Greg14]

Hello members,
I have managed to get my hands on a bunch of XviD encoded AVI files, they were encoded ages ago, and the way they were encoded in wasn't that stable.
The AVI files contain some corrupt frames, and in some cases have audio out of sync issues right around the middle of the video.

So, my real questions are: Is there a program that would scan the AVI files for any kinds of errors and "repair" them? Is there another program that would scan the AVI's video vs audio for the "blank" span at the end of the video that was caused by the Out of Sync audio, and possibly adjust the audio/video accordingly?

Thank you for your time.

[redwudz]

Not really. You could open them in VirtualDub and select 'Ask for extended options after this dialog' and select 'Redirive keyframe flags' and that may clean up the index. You can also cut out the corrupt frames. You can also adjust the audio offset with VD. Play the file with Media Player Classic and adjust the audio sync till it matches the video, then use that offset number in VD.

If the sync error changes during playback, then you can mux out the audio and adjust the audio length in Audacity to match the video, then mux it back. If it has a combination of those sync errors, then you usually have to chop up the file and deal with each part with an error independently, then recombine. It can be a lot of work at times.

One word of warning with Xvid/Divx files or any highly compressed video file. The keyframes are usually widely spaced, 300 frames by default with Xvid/Divx and that doesn't work well for frame accurate editing, so you can cause more sync problems by just removing some. The newer versions of VD have a 'smart render' feature that just re-encodes around the cut point and reduces sync error. Otherwise, I sometimes convert the file to a lossless codec like Lagarith, then do my frame accurate editing, then convert back. But lossless codec files take up a lot of hard drive space.

[Greg14]

Thank you for your reply, albeit I was looking for more automated and time-saving methods. I have tried VirtualDub's corrections and wasn't that satisfied with the results. Plus I don't really have the tim to actually sit down and count how many milliseconds passed from the middle of the movie (when the audio track is about to finish) and until the end of the video itself.

Any other specific suggestions?

Thank you.

[guns1inger]

If you look in the Tools section of this site you will find a selection of repair tools. Depending on what exactly the errors are, one or more of them might help. However only some errors can be easily fixed auto-magically - index problems or other container based issues mostly. Yours sound more serious than that. If this issue is data corruption then it can be harder to clean up short of manually removing frames and adjusting audio accordingly. I don't know of any tool that tries to match audio with video and adjust the timings based on silence at the start or the end. It would be an inherently fraught process, as many films start or end with silence, and no tool could if this was a corrupt, badly encoded file, or an intentional artistic choice. And that is without even trying to work out when the audio started to go out of sync, and therefore where and how to start compensating for it.