Replacing DVD audio (question)

[Colmino]

Well. I have three DVDs whose audio was mastered badly. The audio uses the left channel only. So in order to make the DVDs tolerably watchable, I'm going to have to go in and duplicate the left channel onto the right, and then reintegrate the result back into the DVD.

Actually I already have a solid idea of one way to go about accomplishing this. Grab a VOB, demux, edit, remux. Blah blah blah. Good and all, except that these DVDs have over a dozen multiple-hundred-MB VOBs each. If I go about it one at a time, I'll be looking at doing the process around 40 times. A line has to be drawn somewhere.

So it makes sense to me that somebody's come up with a no muss solution. Load app -> boom, here's your two hours of audio. Reload app -> voila, here's your new DVD image with updated audio freshly muxed. Maybe it won't be as simple as that, but I have to see what I can do to make the project more feasible than the nightmare scenario I outlined above.

[Baldrick]

I have not seen any such tool.

Maybe someone could help you write a script for this, that demuxes the vobs using for example pgdemuxes, replaces each audio track and muxes it back using muxman. If they now support command line arguments.

[greymalkin]

IF this is all one movie, then you could get the 30 day trial of tmpgenc dvd author and create a project from CD..it will create a single MPG file on your computer

[steved3604]

hi:
just had this same type of situation last night. I had a single track (L) with voice recorded onto an avi file from a mono source. (forgot to put the Y cable into both L and R

What we came up with was this. Drop the single channel video and audio into Adobe Pre Elem 4.0 editing timeline.

You will see both of the stereo tracks in the audio portion of the time line. You will see audio only on the one track. The "quiet" track is blank.

Export the "Movie" and change the audio type to "MONO" This is very important. It is usually set on STEREO. (sorry I can't remember the name for were you put in the Video/Audoio output changes)

What it does is give you a mono output on BOTH stereo tracks. Sounds backwards I know. I only tried it with Adobe but any editing program with some control over the audio/video will probably work.

[Colmino]

IF this is all one movie, then you could get the 30 day trial of tmpgenc dvd author and create a project from CD..it will create a single MPG file on your computer

Alrighty. So I went ahead and grabbed that thing. It's flashy. I guess I'll get right down to it with the questions I have now.

1) It imported the dozen+ "titles" from the first DVD just fine. But there doesn't seem to be any way of getting it to import the menu. The menu is very simple and I actually don't use it, but in the interest of completion, it would be nice to be able to include it.

2) The actual task of exporting the audio seems also to be missing. Same deal with replacing the audio. This is version 4 of the software.

For the record, I did initially begin the process of demuxing the VOBs one by one. Even if I were to choose to go about it that way, there is a serious and apparently insurmountable problem. The act of converting AC3->PCM->AC3 invariably causes the resultant audio file to be a tiny bit too long or short. Specifically:

A: If I use AC3Tool to convert AC3->WAV, and then use EncWAVtoAC3 to convert WAV->AC3, the result is slightly too long (ex: 30654464 -> 30655488 bytes).
B: If I use Adobe Audition with ac3filter.flt, both to load the original AC3 file and to save the new one (of identical length), the result is slightly too short (ex: 30654464 -> 30653440 bytes).

I have tested both results in a compiled DVD project, and it sounds like what you'd expect: the audio drifts very slightly until the end of the VOB portion, at which time it pauses (or skips) very briefly, becoming freshly in sync with the next VOB. So the file size disparities are no fluke. Unless there is a way of converting the audio which results in a 100% identical file size, demuxing each individual VOB will get me nowhere. And because of this, I am even more perplexed that there doesn't seem to be an easy solution to what I feel comfortable assuming is a commonly necessitated undertaking (the extraction and replacement of a full audio track in a preexisting DVD movie).

[Colmino]

Just another update on my tribulations. I've attempted to use Muxman to remux a new VOB from a combination of the M2V file PCGDemux had created and the AC3 file spat out by Adobe Audition. The newly muxed VOB is considerably smaller than what I started with (562,262,016 -> 558,129,152 bytes). Nonetheless, I tried replacing the original VOB with the new one and seeing how that played. It did play, but it was impossible to seek around in that portion of the DVD. I then replaced the original BUP and IFO files with the ones Muxman gave me. That made it possible to seek, but the DVD refused to play past the VOB in question.

So obviously there's something going on here which prevents one from simply swapping files. Not that I'm surprised, but hey, I've already spent 12 hours on this with no usable results, so it's long past time to try dubious ideas.

[usually_quiet]

There is programming included in every DVD that controls playback, menu functionality etc. You can't simply swap the VOB files.

Authoring aps can't import existing menus from DVDs. To keep the menu as is, you'll need to learn how to use PgcEdit or VobBlanker to replace the old VTS titles with the new ones, and possibly to revise the programming from the old DVD to work with the new VTS titles. I can almost guarantee that will take much longer for to you figure out than giving up the old menus and re-authoring from scratch.

If you want to take the time to do it you may be able to re-use the menu backgrounds, music etc for re-authoring. Motion menus and music must be demuxed. For still menus, you can use a screenshot. However, you will still need to add buttons and add menu fuctionality with an authoring program.

Also, you have never said whether the DVDs contain single movies, or mutltple individual videos, or how many VOB sets there are. ie are they numbered VTS_01_1.VOB, VTS_01_1.VOB, ... VTS_01_12.VOB = 1 VOB set
or VTS_01_1.VOB, VTS_02_1.VOB, ... VTS_12_1.VOB = 12 VOB sets
Knowing that would help us advise you on how to best replace the audio and re-author. For example, grabbing VOBs one by one is not a good way to proceed if there is only one VOB set containing 12 VOBs.

[Colmino]

The DVDs have 11+ VOB sets apiece, it would seem. However, they play in sequence, seamlessly, as a single movie. It is this seamlessness which eludes me, as somewhere during the acts of demuxing, editing and remuxing, I lose critical sync.

One option which might be available to me would be to demux each of the VOBs and then load all 11+ AC3 files into Audition and splice them there. However, DVD Lab evidently lacks the ability to treat the M2V files as clips which could be spliced together atop one long audio file.

[minidv2dvd]

if all the vobs are in the same titleset and numbered sequentially, then just drag the first one into dvdlab and it will pop up with the question do you want to join and demultiplex all the vobs. click yes and it will demux and join all the vobs into 1 mpv and 1 ac3, the files will be in the source folder with the vobs. take the ac3 file and fix it then use it and the mpv to make a new dvd with dvdlab.

[Colmino]

I had tried that, actually. However, DVD Lab quickly complained:

-> Cause: Not a 11172-2 or 13818-2 Video stream
-> If this is a capture from TV it may have missing/wrong header
-> Please go to Tools and try Fix Stream headers on the file.

Dutifully following this suggestion, I tried loading some of the VOBs up with said Fix Stream headers function. Here's what I got:

Nothing was done.
This is a video SYSTEM file.
This works only on ES files (mpv, m2v)

It seems to be asking for a demuxed video-only file, which would defeat the whole purpose.

[minidv2dvd]

ok so the entire dvds were badly made. open the folder with the vobs with vob2mpg. have it make one mpg out of all of them. demux it. fix your audio. take the mpv and new audio into dvdlab and make a new dvd.

[Colmino]

Vob2mpg doesn't seem to have the option of extracting all of the titles as a single mpg. Even the online help stipulates this limitation.

Well, it's extracting now, at its afore-warned crippled non-pro speed. When it is done, I will see what kind of result I can get from combining the individual pieces with other software.

[guns1inger]

DVD Lab Pro will let you author multiple clips into a single title, called a Multi-PGC Title. You will get a chapter stop at the start of each clip, and connot put extra chapter stops in. Read about it in the help file.

[Colmino]

Thanks for the information. My current goal is to get the whole DVD as a single file - or, rather, a single audio and a single video file.

Anyone care to recommend a simple program I can use to combine the MPG files Vob2mpg generated? VideoReDo forces a limitation which prevents it from being usable.

[guns1inger]

What limitation ?

Straight mpg files, assuming they all have common attributes (resolution, framerate etc), can simply be joined in a command prompt (CMD) window.

Otherwise you could look at Womble Mpeg Video Wizard or Tmpgenc Plus' Mpeg Tools.

[minidv2dvd]

if you don't have an mpg2 muxer you could try muxman.

[Colmino]

What limitation ?

I call it the $35 limitation. ;p The software pointed out that it would not save edits beyond 15 minutes.

Anyway. DGIndex seems to have been capable of doing what I needed. Thanks to all for your help.

I guess all I really need now (assuming I don't hit some brick wall) is an easy way of extracting the chapter information from these DVDs and then importing it into DVD Lab.

[Colmino]

So.. brick wall time. DGIndex combined my VOBs to make two files. A M2V and an AC3. Both play fine. But DVD Lab refuses to be nice. It insists that the M2V is 22:29 long, rather than its actual runtime of 2:00:35. This miscalculation corresponds rather precisely to the length of the final VOB which DGIndex combined to the ones before it. It's easy to take a stab at what went wrong, but I'm at a loss as to how to fix it.

Edit: Adding the M2V to a project gives curious results. The entire video seems to be there, but the clock times are completely scrambled. This incidentally would seem to make the insertion of chapters a confusing or impossible task.

Another edit: What seems to be going on is the timecode present in the M2V has been transparently carried over from the individual VOB files, whose timecodes each began at 00:00. A strange problem which, again, I wouldn't know how to fix.

[guns1inger]

Run ReStream on the m2v file and see if that smooths things out. You may have to set the Reset Timestamps box.

[Colmino]

ReStream did fix it, indeed. Now all that's left is to figure out a good system for extracting what passes for chapters from these DVDs, and then dealing with whatever sync issues crop up after everything is muxed back together.

[guns1inger]

DVD Decrypter can create a file of chapters ready to be loaded into DVD Lab Pro.