Joining 2 videos: synchronise an overlap! (From 2 VHS tapes)

[EuroSong]

I am in the process of capturing footage from Super-VHS tapes, cleaning up the results and encoding them in the best reasonable quality. I use VirtualDub for the capture (Lagarith Lossless codec); apply any necessary filters; then run the resultant .AVI through Handbrake. I've had pretty good results so far.

I have one TV programme, however, which has been split onto TWO video tapes. This is a copy from a studio source, and therefore when the second tape starts, the source has been rewound so there is an overlap: i.e about a minute of footage from the end of the first tape, is repeated at the beginning of the second one.

I can perform two captures, no problem. Exactly the same resolution, colour space, frame rate etc. But now I want to join the two videos together.

Obviously, I could try to align the videos manually to my best ability. I can try to find one time code and frame which looks like it's the same; trim the end off the first video and the beginning off the second one; and then join them. But I know this won't be perfect. Not only will it be laborious to nail down the exact place I want them to join, but even with my best efforts it's not going to be perfect. There may also be a problem with key frames etc, although I'm not sure.

So I wonder if there's a way that either VirtualDub, or any other software, can do this for me? A program which will analyse either the video (or more likely the audio); find the synchronisation; and mesh the two videos together seamlessly?

Any help appreciated! Thanks.

[manono]

There may also be a problem with key frames etc, although I'm not sure.

You said it's Lagarith so every frame is a keyframe. No problem joining. You can easily cut on any frame you wish.

There aren't any scene changes during that minute of overlap? If so, it's easy. Cut one after the scene change, the other before. Append in VDub using DirectStreamCopy or make another Lagarith.

If no scene changes it's still pretty easy. Take a guess (perhaps with 2 instances of VDub open), cut and join and watch it. Here the audio might hold the clue as to whether or not you did it correctly.

There's no automated analysis, no.

[EuroSong]

Thanks Manono. Good to know key frames aren't an issue.

Yes, I think there's a scene change - so I could simply try to cut it as precisely as I can. However it'll still never be as good as a proper auto-analysis which matches up the audio waveform. I'm expecting a little blip if I do it manually. Do you know of any other program which can do something like this?

[manono]

I use AviSynth for something like this but I don't know why you can't use VDub. Yes, it's possible for some kind of audio artifact to occur if they aren't synched up exactly the same in both videos. In such cases where you do get that 'blip', you can always fix it later in a WAV editor, one such as Audacity. Or you can add back or remove an additional frame. Maybe keep track of frame numbers when doing the cutting and joining so it'll be easier to adjust it if you have to do it all a second time.

Using AviSynth is an advantage in cases like this because you can 'play' the script as if it were a video before saving out a new Lagarith AVI, to make sure the video is smooth and the audio is artifact-free at that join place.