Differences VLC & Handbrake and some disappointment

Handbrake is really great for ripping DVD movies but there is a drawback (unless I have missed something).
When scanning a DVD and the scan aborts at some point due to a damaged DVD (from my local library - all those scratches etc.), that's it - no encoding possible.
Fortunately the title in question was not the main movie so I could use VLC to select the main movie title and start encoding (to mp4).
That worked a treat and the mp4 movie which I saved to my Desktop plays perfectly in VLC and default Movie Player.
Now the conundrum.
Devede only recognises the mp4 movie as audio ! Also Gnome Mplayer thinks it's an audio file. Why ?
~$ file -b "The movie".mp4
ISO Media, MPEG v4 system, version 1

Here r/click Properties ..



Next question.

Is there a simple way to check cd's and dvd's by means of a surface scan and a file scan ? Similar to Nero's CD-DVD Speed tool ? (or must I use fsck ?)