How to re-dub audio & ensure synch ?

[captainmetro]

Hi.

I have looked through faq's and tutorials and I see little bits of information that sort of sound like they're what I may need, but all it's doing is confusing me.

I'm hoping that what I need to do is relatively simple.

I have recorded some music videos from an old (like 24 years old) vhs tape to dvdr...all cool...trouble is while the picture looks great the audio is a disaster. It's muffled and the volume goes up and down like a yo-yo

I'm trying to understand how I can remove the audio from the video and replace it with the equivalent audio, but ripped from a cd for example, and how to keep it in synch with the video. Is this possible or am I dreaming ?

I'm reasonably well versed with dvd decrypter, vdubmod & TMPGEnc as far as getting from vhs to a decent quality VOB goes at least, which is all self taught and largely from this site (thank you)...but this is a new challenge and I'm not finding the answers to this one as readily as I have other questions.

Kind thanks in advance.

[Nelson37]

Load existing video in an editor such as Vegas, or anything else which shows multiple audio tracks. Ulead Video Studio will do this, comes free with many cards.

Load secondary audio.

Use the Waveform display to find a nice vertical peak in both audio. Manually line them up, using Time Zoom to get this as precise as possible. Add or remove silence at the beginning to maintain synch. Export secondary audio, encode as needed, demux original video, mux to new.

This assumes the new audio is EXACTLY IDENTICAL to the original. If it is different, then precise alignment is useless. Just cut to the right duration and line up the beginning.

[captainmetro]

Thank you very much for the reply.

You've given me a place to start. I will experiment this weekend.

Invariably I think I will be presented with some obstacles, not the least of which will indeed be a slight discrepancy between the duration of the video and the new audio ripped from the cd. Another bridge to cross when I come to it...but I'm determined to learn how to do this

Thanks again

Load existing video in an editor such as Vegas, or anything else which shows multiple audio tracks. Ulead Video Studio will do this, comes free with many cards.

Load secondary audio.

Use the Waveform display to find a nice vertical peak in both audio. Manually line them up, using Time Zoom to get this as precise as possible. Add or remove silence at the beginning to maintain synch. Export secondary audio, encode as needed, demux original video, mux to new.

This assumes the new audio is EXACTLY IDENTICAL to the original. If it is different, then precise alignment is useless. Just cut to the right duration and line up the beginning.

[Alex_ander]

It is possible and I do such things for myself, even with long concert videos. It's manual job and it takes time of course, depending on how video and audio versions were processed (worst case is if the sources are differently cut-edited). I use Womble for finding the right position of audio pieces on time-line by lip-synch with 0.05-0.1s accuracy. I adjust each wav piece in a sound editor, seamlessly join with other ones ready (fill spaces with applause and use fades where necessary) and put back to timeline for testing the next track added.
The last time I did it, it took me 2 weekend days for a 1-hour program (the sources were in favourable condition at that). The method works for me faster than any attempt of doing it in sound editor only.

[dadrab]

I think you might want to take a different tact.

Live concert footage overdubbed with studio audio is the ultimate insult to me (and that's just me, of course). I prefer to hear what I'm watching.

Do the tapes sound good when you play them in your VCR? If they do, something happened when you captured. A re-capture might be in order.

In any case, if you have good sound on your tapes, there is a way to get that sound to your DVD.

I have a tape of one of the first bands I was in from 1979. We borrowed a video camera from the A/V department of the university where I attended school (my girlfriend worked there and we were threatened with our lives if we let anything happen to it ).

I recently captured that old tape to HDD, extracted and enhanced the sound (Adobe Audition), remuxed and burned the disc. The sync is perfect and our band never sounded so good.

I tell you all that to say that if you have sound worth using on the tape, you can make a good DVD copy. 8)

[hech54]

I do it with freeware all of the time.
If they are just "music videos" and it is the same audio as on the CD/LP....simply get the correct time length of the audio recording from the CD(rip it to a wave file while you are at it)....and edit the video to that exact length in editing software (I use VirtualDub Mpeg). Output that piece of video as an uncompressed AVI or mpeg(depending on your skill...I use uncompressed AVI).
Now reload the video into Virtualdub Mpeg and this time use your CD WAVE audio. Adjust the audio sync under AUDIO - INTERLEAVING and you are done. (I will send you a link to an example I did personally in a PM)

[captainmetro]

I use Womble for finding the right position of audio pieces on time-line by lip-synch with 0.05-0.1s accuracy. I adjust each wav piece in a sound editor, seamlessly join with other ones ready (fill spaces with applause and use fades where necessary) and put back to timeline for testing the next track added.

Thanks for this information. What I'm looking at isn't quite as complex a task...it's literally just taking the audio from a 3 or 4 minute video from a (very) old vhs tape and upgrading the audio to cd quality...but this Womble sounds like something I should also investigate.

Thanks for your answer

I think you might want to take a different tact.

Live concert footage overdubbed with studio audio is the ultimate insult to me (and that's just me, of course). I prefer to hear what I'm watching.

I agree 100%...that's very distasteful indeed...but this isn't live concert footage, it's music videos.

Do the tapes sound good when you play them in your VCR? If they do, something happened when you captured. A re-capture might be in order.

No, it sounds rotten on the vcr too. Somehow the audio track on the vhs tape itself has been compromised...I'm just glad the video is fine...in fact I can't believe how well preserved it is given the age of the tape.

The problem is, I just know already that the video and the ripped audio (from cd) will be slightly out of synch. The likelihood of them being absolutely precise is very, very remote. This is going to be another learning curve for me and no doubt the cause of more grey hairs that I don't need but I'll persevere and come back here in the event of problems

Thanks for taking time to reply.

[captainmetro]

I do it with freeware all of the time.
If they are just "music videos"

Yep, they are...

and it is the same audio as on the CD/LP

It is...

....simply get the correct time length of the audio recording from the CD(rip it to a wave file while you are at it)....and edit the video to that exact length in editing software (I use VirtualDub Mpeg). Output that piece of video as an uncompressed AVI or mpeg(depending on your skill...I use uncompressed AVI).
Now reload the video into Virtualdub Mpeg and this time use your CD WAVE audio. Adjust the audio sync under AUDIO - INTERLEAVING and you are done. (I will send you a link to an example I did personally in a PM)

The information I've had from all who have replied has been invaluable. I just didn't know where to start...now I have an idea. Thank you.

I'm reading stuff here that I have never done and don't know how to do...yet. Demux & Remux...I have no idea how to do that but I do realise it's part of the process of achieving what I want to do.

You refer to "Virtualdub Mpeg"...is that the same as "VirtualdubMod" ?

Thanks for your reply, much appreciated.

[hech54]

I use an old version of VirtualDub Mpeg myself. I have not upgraded it or changed it because I'm afraid to mess up process...

Demuxing is separating the video from the audio into two different "things".
Remuxing is not important when using VirtualDub products....the output will contain both video and audio "remuxed".

Where To Start?
Is this stuff (these songs) on DVDR yet?
Are they on your computer?

[hech54]

Here's a link for the version I use:
http://fcchandler.home.comcast.net/~fcchandler/stable/
It's just newer than mine.

[Alex_ander]

Live concert footage overdubbed with studio audio is the ultimate insult to me (and that's just me, of course). I prefer to hear what I'm watching.

I think no one meant studio audio, just CD, FM or audio tape versions of the same musical event, they are often available in good collection.

[captainmetro]

Where To Start?
Is this stuff (these songs) on DVDR yet?

Are they on your computer?

Hi again & thanks for your support with this.

Yes, video is on the computer as a vob ripped with dvd-decrypter.

[hech54]

Where To Start?
Is this stuff (these songs) on DVDR yet?

Are they on your computer?

Hi again & thanks for your support with this.

Yes, video is on the computer as a vob ripped with dvd-decrypter.

VOB's will work in VirtualDub Mpeg (known as VDub from here on in)...
You will need to install the AC3 audio decompressor on the page I linked to earlier to
hear the audio from the VOB's. That way you can find a good start and end point for the
music video and cut it to the length of the CD audio.

I'm still a VDub "idiot" if you ask me....so if I can figure this out anyone can.

[captainmetro]

VOB's will work in VirtualDub Mpeg (known as VDub from here on in)...
You will need to install the AC3 audio decompressor on the page I linked to earlier to
hear the audio from the VOB's. That way you can find a good start and end point for the
music video and cut it to the length of the CD audio.

I'm still a VDub "idiot" if you ask me....so if I can figure this out anyone can.

Done...thanks for that. I always wondered why I couldn't hear any sound in VDub...I just thought there wasn't meant to be any lol. Well, I guess technically there isn't. That's great though that I now have sound in it. I only know some basic uses for it but it apears to be an invaluable program from what I've read.

Oh and if you're a VDub idot I hate to think what that makes me lol

Thanks again for this

[hech54]

You'll get the hang of it. Just don't forget the words AUDIO up in the top left corner of VDub. That is where you switch to use the CD audio and that is where you find the option to offset/sync the audio + or - .
Using + or - 1000 milliseconds or more is NOT uncommon by the way. It sounds like a lot but it's not. Start off with -500ms and if the offset is worse...go to +....BUT...+ does NOT require a "+"....+500ms would be just 500.