Is there any way to keep chapter stops when demuxing vobs?

[pbush77]

Thanks in advance for any help that anybody can give me! I'll give you the full run-down, so you can be the judge of what I might need to do in order to achieve what I want.

Basically, I have lots of raw dvd's (vob, bup, and ifo files) on my hard drive, authored by me a while ago to be a fully functional dvd. Now, having found a way to convert the audio from boring mono to pretty good stereo, I obviously have to demux the sound from those vob files and re-encode it, right?

The problem then becomes how to re-insert the new sound into the vob file without starting all over again. I tried (using TMPGEnc DVD Author) choosing the old vob file for the video, but changing the audio file (which is automatically set as from that vob file when I add the dvd video file) to the newly encoded ac3 file that I wish to insert. I thought that would do the trick, but re-authoring the disc, unfortunately, didn't work. The sound went crazy on me - it worked fine for half of each clip and then re-set itself to make the second half of each video clip repeat the sound from the first half again! I have no idea why it did this, or any ideas how I could get around it using the same method.

So, the only way that I know I can insert my new sound for sure, is to also demux the video from each vob file (into m2v), and then to remux that with the NEW ac3 file through TMPGEnc Plus. Of course, that only creates an mpeg2 file, which doesn't contain the chapter stops. I went to great pains to insert these chapters when I originally authored the dvd's, yet if I then insert that mpeg2 file into TMPGEnc DVD Author, I lose all my chapter stops. I'm talking about 100 video clips here, each having around 7 chapter stops. That's an awful lot to find the right place and re-insert them, so I'm hoping that somebody has some ideas to help out!

1) Is there any way that anybody knows of for me to demux the video from the vob file, yet KEEP the chapter stops contained within it for when I remux it into an mpeg2 file? I know that would mean having a standalone mpeg2 file with chapter stops, which may not be possible, but if it can be done, hopefully someone knows how to do it.

or

2) Is there a sure-fire way for me to insert the new ac3 file into the old vobs without corrupting the sound in the vob file? I realize that it's probably somehow trying to join the old sound contained within the vob with the new sound, but is there any way around this (completely overwriting the old sound) so that I could keep the chapter stops which are already in the file?

[mats.hogberg]

The "chapter stops" aren't part of the VOB or m2v or mpg - they are in the IFO, AFAIK. Depending on what you use to author, you should be able to get the chapter info from your sources in some format that your authoring application can take as input.

/Mats

[pbush77]

That makes sense about the IFO files - hence standalone mpeg2 files don't have my chapter stops when they are remuxed.

Well, I initially used TMPGEnc DVD Author to create the VOB and IFO files, and I am using the same program to re-author it. How would I use those IFO files to insert the correct chapter information in a remuxed mpeg2 file? (i.e. demux m2v, remux it with new ac3, insert the resulting mpeg2 file into TMPGEnc DVD Author, and then how would I get the chapter stops from the old IFO files into that?)

Thanks for your help!

[mats.hogberg]

No idea, frankly, cause I use IfoEdit. DVDDecrypter can get you the chapter points from a DVD in text format IIRC...

/Mats

[pbush77]

What would happen if I did this?

1. Demux the video from the VOB file
2. Remux the produced m2v file with the new ac3 file
3. Insert the produced mpeg2 file into TMPGEnc DVD Author
4. Re-authored the DVD
5. THE KEY PART - replaced the newly re-authored IFO files with the OLD IFO files

Bear in mind, I'm talking about NOT inserting any chapter stops after inserting the mpeg2, but trying to rely on the old IFO files for that information. The video is exactly the same, so would this work or would it just be corrupted?

[pbush77]

Does anybody have any ideas if my proposed solution will work? Somebody told me that, it should, in theory - as long as the resulting file size is the same.

If this is true, it leads to this question. If I extracted the ac3 audio from a file, converted it to a wav file and then edited it, re-converted it back into ac3 audio, and then reauthored the file... would the resulting VOB be the same size as previously (bearing in mind I wouldn't have altered the video at all)? I am unsure as to whether all ac3 audio files are the same size, etc., so it's a bit confusing.

Thanks for any help anybody can give me!

[Suntan]

You can also use chapterxtractor, which will compile a list of chapters from the IFO file. FWIW...

-Suntan

[pbush77]

Thanks, Suntan, but do you know how I would then apply those extracted chapters to the new file? The official site for that tool does not seem to work, so I'm struggling for information. Any ideas on whether my other suggestions would work?

[BobK]

Since you're using TMPGEnc DVD Author you can just click on the 'Add DVD Video' button and add the DVD video directly from the disk (or from the files ripped from the disk). When you do that you get the option to read the chapter information as the files are opened by DVD Author. No demuxing, no remuxing- just one easy step.

[pbush77]

Sorry, I guess my long post was too hard to read! I already tried that, BobK, although I appreciate your help.

What happened when I did that was that it read the chapters no problem, but when the file was authored the resulting vobs had their sound corrupted. At the halfway point the sound started all over again, although the video continued as it should have. Pretty weird, huh? I tried re-authoring it a second time using the internal ac3 encoder, but got the same result, so I'm pretty sure that splitting the sound and video that way is not going to work, although I have no idea why TMPGEnc DVD Author does that! (It must be something to do with the previous audio already being in the vob file)

[Suntan]

Sorry, can't help you past that as I don't encode Mpeg2. I just use it to pull the chapter points for my Xvid encodes.

[pbush77]

That's okay. I appreciate the information. Anybody else know enough to help me out? I am most concerned right now with whether my proposals to the problem will work or not.

[BobK]

When you tried using DVD Author the first time, did you substitute the stereo sound for the mono sound? If not, try letting DVD Author do the remuxing for you. First demux and convert the audio to ac3, then go back to DVD Author and open the original DVD Files. Go to the clip information page and click 'Browse', then select the new audio file.

I haven't tried that with ac3 files, but I have replaced the audio with a cleaned up wav file and it works fine.

[kernow_warrior]

can you not re-author with something like dvd maestro?
1) extract audio/video streams using dvd2avi
2) extract chapter points using chapterxtractor
3) do what you have to with the audio
4) run video through tmpgenc
5) bung it all in dvd maestro and compile

you should now have your video clips with their original chapters and your converted audio

[jimmalenko]

Copying old IFOs would not be my preferred method. It is extremely wishful thinking IMO that the file sizes would be exactly the same and therefore the old IFOs would still work.

I would demux into M2V, convert the audio to AC3, extract the chapters to a text file using ChapterXtractor and put the whole thing back together using IFOEdit. This will multiplex the video and audio and re-insert the chapter points, as well as creating your IFOs, BUPs and VOBs, all in one operation.

Try Step 2 in the guide here.

[Megahurts]

pbush77

Tried your process of replacing the new VTS_XX.IFO with the old one. However the DVD player did not know how many chapters there were but I could skip through the chapters.

To correct this, use IfoEdit to edit the new VIDEO_TS.IFO file.

Click on VMG_PTT_SRPT/Title_X: Number of chapters (PTT), and enter the new number of chapters. Save and click Get VTS sectors because the VOB file sizes were slightly different.

Hope this helps

Chas

[pbush77]

Ah, this is all EXCELLENT information. Thanks so much for your help, guys!