Freezes computer, if a video file is passed as the input file

[Jarno Suni]

I ran "mogrify -strip somevideo.mp4" to strip a video from unneccessary metadata, but mogrify started a denial-of-service attack and started to occupy huge amounts of memory. If it cannot handle video files, it should exit with error, instead. I have tested only with one video.

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: imagemagick 8:6.7.7.10-5ubuntu3
ProcVersionSignature: Ubuntu 3.11.0-14.21-generic 3.11.7
Uname: Linux 3.11.0-14-generic x86_64
ApportVersion: 2.12.5-0ubuntu2.1
Architecture: amd64
Date: Sun Dec 15 13:04:05 2013
EcryptfsInUse: Yes
InstallationDate: Installed on 2013-09-20 (86 days ago)
InstallationMedia: Lubuntu 13.04 "Raring Ringtail" - Release amd64 (20130423.1)
MarkForUpload: True
SourcePackage: imagemagick
UpgradeStatus: Upgraded to saucy on 2013-10-18 (57 days ago)