[MPlayer-users] convert 8GB DVD to 4GB DVD

[Noah Spurrier]

I have a bunch of 4GB DVD disks (single layer). I was thinking that
it should it easy to convert some 8GB DVD images I have down to 4GB.
I mount an image and then converted each VOB to a VOB with lower
vbitrate and abitrate. I kept all the original .BUP and .IFO files.
I thought this would be quick and dirty:
    mencoder VTS_01_1.VOB -o /tmp/VTS_01.VOB -oac lavc -ovc lavc \
    -lavcopts acodec=mp2:abitrate=128:vcodec=mpeg2video:vbitrate=3000
I did that for each VOB to produced a set of VOB files of about
the right size to fit on a 4GB DVD (I actually could have gone higher
for the vbitrate). I then recreated the VIDEO_TS directory
structure with the original BUP and IFO files and new, smaller, VOBs.
Each VOB would play fine in mplayer, but the new image would not play
in any DVD player I tried (settop player and VLC).
So, either the BUP and IFO files are somehow dependent on the
original VOB files or I'm completely wrong headed about all this.
Is there a simple way to do this or do I have to remaster even the
DVD menu?

Yours,
Noah