Concatenating DVD VOBs: AlignedSplice() or UnAlignedSplice()

[fvisagie]

Hi All,

I'm making a little script for concatenating DVD VOBs for encoding purposes. According to the Un/AlignedSplice() documentation:
You should use UnalignedSplice when the soundtracks being joined were originally contiguous

However, I'm unclear as to how soundtrack timing gets handled when DVD VOBs are created. Put differently, which of AlignedSplice() or UnAlignedSplice() is generally recommended for concatenating VOBs?

Many thanks,
Francois

[Ghitulescu]

Why don't you use DVD-aware concatenating tools? Like creating a large VOB before feeding it to AviSynth? You can even use the DOS COPY command :)

[fvisagie]

I could, but I'm trying to avoid adding another step to the process! (The .avs script will be generated automatically.)

So I'd prefer to do the concatenation in Avisynth.

[TheSkiller]

You shouldn't do it this way. See, the VOBs are not simply individual video files, they are one big file that has been split exactly at 1GB boundaries. That means the video and audio bits are suddely continued in the next VOB.

Thus, if you open every VOB as if it was a stand-alone video file you might get errors in the video and audio at the join points.
So, if you insist on doing it that way, use AlignedSplice.


My recommendation, Ghitulescu mentioned it as well, merge the VOBs first. VOBMerge (http://www.videohelp.com/tools/VOBMerge) does it nice and fast.

Edit: Or just use DGDecode/MPEG2Source, no need to join then.

[fvisagie]

Thanks for the suggestions. I'll play around and see what works best for me.

Cheers,
Francois

[StainlessS]

JFYI, as already stated, a real VOB comprising of the visible VOBs on DVD are written on consecutive sectors of the DVD,
the reason for the visible DVD partial VOB's is down to Operating system / File System limitations of size, some will
fault at 4GB (32 bit), some at 2GB (31 bit) but usually safe at 1GB. This allows you to safely copy partial VOB's to
eg FAT32 file system drive and process them in 1GB chunks.

EDIT: Above, I meant process as a file, rather than as video.

[fvisagie]

Just to confirm in theory (I'll do in practice :)), if individual VOB files can indeed be considered hard cuts without any sync adjustment, then one would want to rejoin them without any audio/video sync adjustment (e.g. that's why "copy VOB1+VOB2... VOB" has always worked). In other words, in Avisynth one would use UnAlignedSplice() to avoid sync adjustments, as the manual suggests, correct?

[TheSkiller]

The VOBs are not "cut" but split, similar to how a ZIP/RAR archive can be split into parts. The split occurs in the middle of a video and audio frame and those frames affected cannot be decoded properly without the remaining data of that frame (or GOP) which is in the next VOB.

[StainlessS]

fvisagie,

If you are looking to automate VOB concatenation, perhaps take a look at DGIndex Batcher, it might assist.
You run the batcher and give it a list of VOB's (or mpegs, via a GUI fileselector) and it can concatenate
contiguous sets, and then execute DGIndex and index the selected VOB sets, producing d2v and also AVS
(from a template).

forum.doom9.org/showthread.php?t=163369

[creaothceann]

DGIndex can use split VOBs, too.

[hello_hello]

If it's a standard DVD, try opening it (or the ripped files) with DVDShrink. Use the re-author function to include just the titles you're wanting to encode. DVDShrink won't join titles, however.......

Once you've re-authored the DVD make sure DVDShrink isn't trying to shrink it, and look for the option regarding splitting vob files. It's either in DVDShrink's preferences or it's found in the window when opens when you run a backup. Tell DVDShrink not to split vob files and save the reauthored DVD to a new location. When it's done, each title (ie movie or TV episode) will now be in it's own single, self contained, (possibly large) vob file.

If each title is a separate vob file or set of vob files there's no need to use Splice. Just use DGIndex for indexing and extracting the audio (is that what you're doing?)

Generally if I want to encode multiple titles as a single file (DVD extras, for example), I encode them individually after re-authoring with the above method, then append the output files together. Using MKVs at least, it's never caused me audio sync problems.

[fvisagie]

This has been my key learning here

The split occurs in the middle of a video and audio frame

(I guess not necessarily). I'm still very grateful for all the other explanations and suggestions given, too.

Cheers,
Francois