[FFmpeg-user] Transcoding from VOB - sometimes works, sometimes not

[Carl Eugen Hoyos]

Am Di., 14. Apr. 2020 um 06:30 Uhr schrieb Benjamin Hill
<benjaminhill at gmail.com>:
>
> tl/dr: Is there a "best" ffmpeg "try every technique you got to transcode a
> file to a consistent format, ignoring errors, and use the best method, I
> believe in you, thanks!"
>
> long version:
>
> I've got some VOB files from old home movies, ripped from 8mm to DVD.
> (Thanks Dad!). And I'm looking to get everything uploaded to Google Photos,
> so I need it all in a consistent and Google-friendly format.  The problem
> is that whatever service he used had mixed results (they are not great)
> some missing chunks, maybe a DVD scratch, plenty of warnings like "Missing
> picture start code", "Could not find tag for codec mpeg2video in stream #0,
> codec not currently supported in container" - you know... junk.

vob files are not always meant to be played / decoded by ffmpeg,
one alternative is to use mplayer -dumpstream first to get a stream
file that ffmpeg should understand.

> Sometimes they can be easily copied to m4v format, sometimes not.  I've
> fought with it long enough that I cobbled together a "try each of these in
> order, and if the first option works, it is fast, but if it doesn't work,
> move on to the next less-fast option, keep going until it works or you've
> run out of ideas."
>
> Which is strange, I thought they were all mostly the same MPEG-2 format.
>
> ffmpeg -i  MYINPUT.VOB -c copy MYOUTPUT.m4v. # super fast, copy

If this works, you found a bug in FFmpeg, feel free to test with "mov" or "mp4".

> ffmpeg -f mpeg -i  MYINPUT.VOB -c:a copy -c:v libx264 -crf 18 MYOUTPUT.m4v
> # Force declare the file format
> ffmpeg -i  MYINPUT.VOB -c:a copy -c:v libx264 -crf 18 MYOUTPUT.m4v #
> Generic transcode
>
> My question: Is there a way to combine these?  Some sort of "use all of
> your wizardry and ignoring-of-errors and advanced decode options to salvage
> whatever you can, ending up with a m4v format."

Why would you want to combine them?

For all questions, please do not provide command lines only, always
provide the command lines you tested together with the complete,
uncut console output.

Carl Eugen