I have used successfully the software "Handbrake" which is open-source(free). It can shrink the video even for phones. BUT do not expect speed...
Converting a video, using a Notebook with Dual core processor, T9400 / 2.53 GHz - 4GB RAM, Vista 64-bit, peaked at 17 fps. Which means that an 1 hour video needs something less than 2 hours to be converted down to PAL sizes.
I tried also the much much faster Badaboom, which works and needs a latest-version GeForce card and converts at up to 100fps... but sometimes it loses sync between sound and video. It costs less than 30 dollars. Sound ends earlier than the video... I hope that they will fix this in a patch...
Since sound of 5D Mark II is anyway terrible, you can use this software for fast conversion of image-only video.