Taking a DVD apart, replacing audio, and putting it back together

[harryk]

I have an old DVD which is a film of a stage production. It has two acts, and a menu in which you can select Act I or Act II.
Unfortunately, Act II has a lot of noise (electrical hum). I have very little video experience; but I have used Audacity in the past for noise reduction on audio; and so I thought I would try to use it to clean up the sound in Act II.

I have managed to extract the Act II audio (as a .wav file) using DVD Fab Decrypter (in addition to .avi, .idx, and .sub files for each act). Noise reduction results with Audacity were good. But I have no idea how to put it back together as a DVD.

I'm guessing I still need to do something like
1. split the .avi file for Act II into separate video-only and audio files
2. replace the audio with the new one, and combine the two back into a .avi file
3. burn a DVD from the .avi, .idx, .sub files (hopefully without losing the menu)

Can someone recommend good tool(s) for this?

Thanks for any help you can offer.

[manono]

I'm guessing I still need to do something like
1. split the .avi file for Act II into separate video-only and audio files
2. replace the audio with the new one, and combine the two back into a .avi file
3. burn a DVD from the .avi, .idx, .sub files (hopefully without losing the menu)

1. No, throw away the AVI.
2. No.
3. No.

1. Demux the Act II from the DVD (PGCDemux) into audio (which you'll toss since you no longer want or need the original), video, chapters (celltimes.txt), and subs.
2. Reauthor with the new audio (Muxman).
3. Open the original DVD and replace the old Act II with the bad audio with the new one with good audio, thus keeping the menus and anything else you might want (VobBlanker).

You don't want to ruin the original video by making an AVI and then reencoding it back to DVD video. Use the original untouched video.

[harryk]

Thanks manono.

I take it that you are saying that .avi is poorer quality video than what's on the DVD. I didn't realize that, and am glad that you have rescued me from that mistake. I will try out the tools you have suggested.

[jman98]

This guide will show you how to do what manono is talking about.
https://forum.videohelp.com/threads/277950-How-to-add-new-subtitles-to-an-existing-DVD
Skip the subtitle stuff. Just replace the audio with the new one, but follow the procedure in this guide. This is exactly what he said to do but with screen shot and such that may help you.

[manono]

I take it that you are saying that .avi is poorer quality video than what's on the DVD.

Yes, much poorer, unless you made an uncompressed AVI (using Lagarith or some such codec). If it's XviD or DivX, it's a shadow of the source DVD quality.

jman98 pointed to a good guide for what you want. Follow Baldrick's Method 2 in that guide, ignoring the stuff about subtitles. There's one thing different and that is you're not replacing a single movie but one part of a 2-part opera. It's important that when using PGCDemux (and later VobBlanker) you find the Part II. It may be a different PGC within the same VTS (or IFO), or a different VTS (different IFO) altogether. If you know its length before starting you should be able to track it down.

And when using Muxman, don't forget to load the celltimes.txt in File->Import Chapter. If you don't, then no chapters in that Part II and VobBlanker will complain like crazy. After authoring with Muxman and before doing the 'Replace' step in VobBlanker, test your new DVD with a software DVD Player (not a file/VOB player). Make sure everything looks OK and you have subs. Ignore the subtitle colors. They should come out OK in the end.

[harryk]

Possible problems with step 1.

When I "Process!" VTS_01_0.IFO (which apparently contains BOTH acts), it runs for about 5 minutes, and then I get "Error reading input VOB: Unsynchronized" followed by "Finished OK." When I look at the target directory, there are only two files:
AudioFile_80.ac3 (~256MB)
VideoFile.m2v (~3.5GB)
So there is no celltimes.txt file (due to the error shown above?)

So my questions:
1. Is it a problem that there is no celltimes.txt?
2. I guess there's no easy way to replace the second half of that audio file with my new version? I'm thinking I probably just want to run the full audio file through Audacity Noise Removal again, concentrating on the second act portion.
3. But there is another .IFO file in the same subdirectory (VIDEO_TS), called "VIDEO_TS.IFO" which I presume I also need to process, so it will end up on the final DVD (it's much smaller, and I think it contains the menu). After processing it, I get three files:
celltimes.txt (0 KB)
Subpictures_20.sup (5KB)
VideoFile.m2v (30KB)
Will it be a problem when I put everything back together that the two video files have the same name?

4. Also, the DVD shows another subdirectory (VIDEO_RM) with files
SONATA.IFO
SONATA_DEBUG.IFO
VIDEO_RM.BUP
VIDEO_RM.DAT
VIDEO_RM.IFO
and pgcdemux rejects those as invalid .IFO files. Do I need to do anything with the files in that subdirectory? Are they needed on the final DVD?

Thanks for your help.

[manono]

Possible problems with step 1.
When I "Process!" VTS_01_0.IFO (which apparently contains BOTH acts)...

And the time shown is for the entire opera? And when you hit the little drop-down box down-arrow, no other PGCs are shown, one of which might be from just the second part? And in the menu there's no option to both 'Play All' as well as 'Play Act 1' and 'Play Act 2', or words to that effect?

Do me a favor. Open the DVD in VobBlanker, highlight the VTS with the opera in it so it shows in the bottom pane as well. Take and upload a picture of that here.

Because what you've said means an authoring error which makes what you want to do exponentially harder to accomplish.

1. Is it a problem that there is no celltimes.txt?

It means the demux didn't complete. You can get the celltimes.txt file elsewhere, but I don't think either the audio or the video is complete. When you play the audio, does it play through to the end? You can skip to right near the end to check. You didn't get the subs in the form of a SUP file?

2. I guess there's no easy way to replace the second half of that audio file with my new version?

As you suspected, if there's only a single PGC for the whole thing, this will mean working mainly on the second half of the opera, but with the whole thing opened in Audacity. It will also almost certainly mean audio synch problems (and the same with the subs).

3. But there is another .IFO file in the same subdirectory (VIDEO_TS), called "VIDEO_TS.IFO" which I presume I also need to process,

Nope, you don't need to do anything with that one.

4. Also, the DVD shows another subdirectory (VIDEO_RM) with files.
.
.
.
Do I need to do anything with the files in that subdirectory? Are they needed on the final DVD?

Not needed now. I don't know what's in them. Maybe play the DVD in a software DVD player and find out. Someone else might know better than I what they contain. Was this DVD made with the use of a DVD recorder as opposed to being a professionally produced retail DVD?

[harryk]

Hello manono,

Thanks again. Some answers, as best as i can.

Yes the time shown is for the entire opera (~2h16m).
As I recall the menu only had "Act I" and "Act II" options.

VobBlanker (attached) does show 4 PGC:
01 = Act I (1:15:14.00),
02 = Act II (1:01:27.15),
03 = ?(Duration is that of Act I; but size =0)
04 = ?(duration is that of Act II; but size =0)

When I play the audio, it does play all the way through to the end (both acts with a brief pause in the middle).
Similarly the video also contains both acts.

I've done some processing on the second act audio. So I guess I'll try step 2 and see what happens.
If I want to test playing with a "software DVD player", what would you recommend?

[harryk]

By the way, this is not a commercial DVD, though I'm not quite sure how it was produced. But it was "filmed" with a fixed camera during a live stage performance.

[manono]

You're in luck. You want the PGC that's 1:01:27 long, the first one showing as that length. The PGC 2. Use the drop-down box in PGCDemux to get it and hope you don't get that unsynchronized error again. If you don't get that error and are successful in demuxing the audio, video, celltimes.txt and the subs (SUP file), and then make a new DVD of it with Muxman and your fixed audio, if you have any problems using VobBlanker to do the replace step (you'll be replacing that same PGC 2 as shown in your picture), then come back here.

If you get that same error, then the whole process might become longer and harder. Maybe not, though, since you said when demuxing the entire thing you got a complete audio and video.