How to synch audio cd source to existing dvd, properly (possible ?)

[bidelman]

although this may be common fare to the ace's out there, I am a novice as such and need to know if this idea is worth doing, and what programs I need to do it with.

Long ago I transferred a couple of my MTV concert vhs tape masters to dvd via a standalone machine.
Two of the shows were only recorded in linear mono (before I had a hifi stereo unit).
I did capture both shows on cassette from an fm simulcast. I still have the tapes, and have not transferred them to anything.

Is is possible to assign those audio tracks to the dvd's with authoring (?) software of some kind.

In days past, I was told trying to synch the two together was impossible. That advice was about 8 years ago.

I figured it would not hurt to ask here.

Thanks,
Steve

[themaster1]

(assuming the original audio recording is well in sync with the video)
The idea would be to put the original audio recording (and it's BPM) on one track, leave it "as is" , add another track that contain the audio from your cd and mix it , arrange it so the two match.At the end you would have to mute the original audio indeed.

Such thing is possible in audio mixing softwares, i do it regularly, not with long videos though (10 min at most) but i guess it's feasible.

Try Mixmeister for example but there are others

[guns1inger]

I did something similar with an old NTSC VHS recording and CD audio. I used Vegas, cut everything up into bits and synced each track one at a time. Unfortunately a couple of the tracks were very different on the CD version, so I kept the original and cleaned it up the best I could. Took about a day to do it all.

[bidelman]

This sounds intensive. The concerts are about 70 mins each.

Thanks,
Steve

[AlanHK]

This sounds intensive. The concerts are about 70 mins each.

If your tapes are from a simulcast, it shouldn't be too hard.


I'd do it in the Audacity audio editor.

First digitise the tapes.
Plenty of info here about that.
You might do some light noise removal in Audacity.

But take care not to cut or paste anything, that will affect the sync.

Then demux the DVD.
Import the audio into Audacity -- (latest betas of Audacity with ffmpeg can import and export almost everything).

Use the original DVD audio as a timeline -- don't edit it at all -- and sync the tape version to that: use the "Time shift tool" to align the beginning. Then go to the end and see how much out of sync they are.

You can selectively mute tracks so you can hear each track separately, then un-mute to hear overlaid.

Note the exact lengths of each track. If no difference, you're done, but probably there will be a small difference.
You can use the Effect "Change tempo" to stretch the new audio to the exact same length as the old.

(Audacity has a very effective "undo", so don't be timid with adjustments.)

If they really were simulcast, that should be it.

But scan through the track and compare the sync at various points -- you can see loud abrupt sounds as peaks which should align all the way through.

Export the new track (make sure you don't mix in the old one) to an appropriate format (AC3 at a good bitrate for DVD) and reauthor the DVD with the original video.

[bidelman]

Thank you very much, I am compiling all the knowledge I am getting here.