Avisynth - just use the VOBs or convert the VOBs to MPG first?

[pooksahib]

Hi. I routinely use MeGUI and have been in the habit of indexing VOB files at the start of the avisynth scripting process. But I read something that suggested you should convert the VOBs to mpg and THEN do your avisynth work.

Does it make any difference? Thank you.

[manono]

Yes, it makes a difference. You've wasted the time it takes you to convert the VOB files to MPG. Use the source VOB files. They both contain the exact same MPEG-2 video and DGIndex will handle them both exactly the same.

[jagabo]

Occasionally you'll find a VOB set with interleaved content -- two different versions of the video. Those need to be converted to MPG with VOB2MPG to isolate only the one you want.

[pooksahib]

Excellent, thank you.

[LigH.de]

Most important though: AviSynth source plugins can process only one PGC (Program Chain) and one video angle. So in general, don't use VOB files as they are authored on a DVD, especially not commercially produced (except you know for sure they are minimalistic, like coming from a camcorder or DVD recorder). Professionally authored DVD content often contains confusing content for source plugins (e.g. quirks to ensure you have seen the FBI warning), only important for a DVD player which plays the whole disc and interprets logical information in the IFO files; these extras may cause async audio if processed and not excluded.

And another remark: Only DG*Dec* plugins can handle a set of VOB segments. Most other source plugins can only handle one continuous source file, but no playlist. So when you are about to rip your consumer DVD, you may want to produce a "PGC VOB" which contains only the main movie (in one angle, if there may be several) without segmentation into 1 GB parts.

You may also want to demultiplex desired audio streams to separate files (possibly to be multiplexed back into the recoding result as they are), but keep subtitles in the PGC VOB (VSRip can handle them easily this way).

[pooksahib]

Danke, LigH.de.