Resync DVD with new audio - without re-encoding

[phozz]

Hi all,

I am an avid downloader of concert videos and as I have purchased a DVD writer I have recently started downloading and burning DVDs.

Sometimes a situation occurs in which the video I have downloaded contains crappy audio (what the camera picked up) while I have a much better copy of the audio from the same show, say a soundboard recording. I want to synchronize my audio with the DVD's video WITHOUT re-encoding the video. The menus and chapter structures must not change either, I'm not going to re-author perfectly good DVDs.

Here are the steps I have done so far:

STEP 1 - RIP. Convert the series of VOB files from the downloaded VIDEO_TS folder (they're separated into 1GB chunks) to a single video file that can be handled by video editing software.

I used SmartRipper to concatenate the VOBs and then used Virtualdub-Mpeg2 to temporarily convert the video to a format Vegas has no problem with in real-time (MJPEG) as my PC is rather slow.

STEP 2 - WAV. From my sound source, create a WAV file perfectly synched with the video.

Vegas is pretty good with this sort of job and I now have a WAV file nicely synched with the original video (I've deleted the temp MJPEG file).

STEP 3 - MUX. Multiplex the new audio, preferably uncompressed (PCM audio) or compressed ac3 with the original video, separating back into 1Gb VOB chunks. These new VOBs should, hopefully, work with the present menu/chapter structure and not require re-authoring of the DVD.

I have used DvdIt for this - it multiplexed without re-encoding anything - but the resultant DVD does not contain the menu/chapter structure. I tried copying all the files except VTS_01_?.VOB from the original DVD to the folder created by DvdIt. The result had the menus but the next-chapter button is grayed out during playback - very weird (the prev button does work though). I also guess my hardware player won't like this.

Basically I have a feeling there's a right way to do this, and I'm not doing it. Can anyone clue me in as to the proper way?

Thanks in advance,

-phozz

[Dimmer]

You're not supposed to mention here any illegally obtained material such as downloaded DVD and concerts shot with a camcorder.

MODs will probably close this thread.

[phozz]

Amateur videotapes of concerts are not inherently illegal; there happen to be bands that are taper-friendly!

[burnout]

sounds to me as if you haven't added the chapters which has to be done in the multiplex stage. use a program like ifoupdate, ifoedit or chapterxtractor to save the chapter list.

for the mux part i would use ifoedit instead as it is simple and will do what u need. save the 'celltimes.txt' chapters from the original IFO, then use the dvd author function of ifoedit loading in the required tracks and celltimes.txt file and then compile. copy your original files excluding VTS_01_1.VOB _2.VOB and so on to a new folder, then copy the newly authored VTS_01_1.VOB and any others after it to this new folder. now use ifoupdate to finish the job, should work fine.

[phozz]

Thank you, this is exactly what I needed - I really appreciate your help!

My only problem is the last step: You say "now use ifoupdate to finish the job, should work fine" - however this seems to do more harm than good. While the project seems to work 100% correctly (in WinDVD) before doing this (with the original IFO/BUP files and the newly multiplexed VOBs), the following occurs after I use ifoupdate:

* From title menu, can't select any chapter except first.
* During playback, can't skip to any chapter.
* WinDVD allows user to select chapter to play, but selecting anything other than 1 will stop playback.

As I said, if I do not use ifoupdate everything does seem correct but I assume from your message that it is required. So.. What am I doing wrong? For "original IFO path" I give the currently functional DVD folder (with old menu structure and new VOBs). For "Authored IFO path" I give the path with the files that ifoedit created when multiplexing.

Thanks for any further tips.

[burnout]

make sure it is in standard mode, on the options menu make sure the top 3 are checked, the next 2 can help, but can sometimes cause errors (try with them checked first and then to find out if an error occured open the ifo in ifoedit and then try and re-save, if ifoedit says there is a problem then restore backup ifo and uncheck the 2 options), then lower down there is another group of 3 which should all be checked, and then check autocorrect ifo/bup length.

these settings should give a successful update (i'm guessing the concert was a single PGC, or you have authored it as a single PGC). and yes, u have selected the correct ifo's to use.

(also are u sure all the chapter frames from celltimes.txt were loaded into a list and none were missing, this could be a possible cause of your problem)

hope this helps, otherwise i'm not entirely sure what the problem will be.

[phozz]

It worked!

Mystery solved. Turns out that ChapterXtractor was creating a file in a format IfoEdit couldn't understand, therefore the authored DVD didn't actually contain any chapters. Since IfoUpdate also contains chapter extraction, and an option to explicitly create IfoEdit-compatible files, I used that.

Now that I have this process more or less nailed, here is my quick tutorial for the benefit of the audience:

Resyncing dvd with new audio:

IFOUpdate: Load original VTS_01_1.IFO. File > Save chapter files > Check IFOEDIT file, save as celltimes.txt
VOBEdit: Open > select first VTS_01_1 on original DVD. Demux, select all video, all audio, and go.
If field order on original was wrong, use PulldownBatchFE: Options menu, set "tff" to "odd". Then start conversion.
Virtualdub-Mpeg2: Convert mp2v to MJPEG. 320x240, mid quality is good enough.
Vegas: sync audio with MJPEG. Render as 48khz WAV (or mp2 or ac3). Delete MJPEG.
IfoEdit: DVD Author > Author new DVD > fill in blanks with original mp2v, new audio, and celltimes.txt. Author into empty VIDEO_TS directory.
Move *.ifo, *.bup from VIDEO_TS to separate "authored" folder.
Copy all files except new VOBs from original DVD to VIDEO_TS folder.
IFOUpdate: Set "Original IFO" to VTS_01_0.IFO in VIDEO_TS. Set "Authored IFO" to VTS_01_0.IFO in "authored" folder. Backup wherever. Update and correct VTS sectors.

That's it, DVD should be ready for burning. Good luck :)

phozz

[burnout]

just a few points, you should demux by vobID or cellID if you are trying this on a commercial DVD to keep the original DVD structure (unless it has only 1 vobID in the first place), the smartripper and tmpgenc step could be combined into one with DVD Decrypter using stream processing (possibly do this with smartripper too but i haven't used it for a while).

just wondering did u keep the audio as .wav? i would encode it to ac3 or mp2 ;)

[phozz]

Thanks for the tips. As for audio, why bother, there's plenty of space on the discs.. I would convert to ac3 if I need the space though.

[phozz]

hi burnout, another little question if I may:

Suppose I've performed the authoring step in IfoEdit as you mentioned, but then I notice that the chapters, while still there, are not as accurately placed as they were before.. any idea (a) why this happens, and (b) is there any way of tweaking the positions of the chapter transitions other than editing the celltimes.txt file and re-authoring (30 minutes of disk thrashing.. ouch..)?

thanks

[burnout]

chapters have to be placed on i-frames (think that's right) which would explain why this happens, but i'm not sure what that changes if you didn't re-encode the video. maybe ifoedit gets the chapters 1 frame out and then scans to the next i-frame to place it there, never noticed this so will look into it soon. and for tweaking chapter positions i think the only way is to re-author :(