convert decrypted .vobs to .avi with ffmpeg on ubuntu

The default encoding options are low, audio bitrate is 64k for example. You can up these values with extra command line options:

ffmpeg -i sourcefile.vob -ab 128kb -qscale 4 newfile.avi

-ab 128kb sets the average audio bitrate to 128kb, and -qscale 3 sets the video quantizer scale, where q is 1 (best) or 31 (worst) quality.

For comparisson, for a 5 minute video of 700x576 resolution with 128kb audio:

• q 10 = ~40MB
• q 4 = ~80MB

Taking this another step, you can batch convert a whole bunch of vob's in a directory with this bash command:

for f in *.vob; do ffmpeg -i "$f" -ab 128kb -qscale 4 "${f%%.vob}.avi"; done;

We enclose $f in quotes in case there are spaces in the file names, and ${f%%.vob} removes the vob extension before we add our own avi extension. (This is parameters substitution in bash, very useful! http://tldp.org/LDP/abs/html/parameter-substitution.html)

There are plenty more options you can read through at: http://www.ffmpeg.org/ffmpeg-doc.html