archive video makes poor choice of video to display in some cases

The code logic to select the video to display simply picks a random .mp4 file to display. This could easily lead to either a lower quality file, or possibly too large a file to be selected.

The preferred behavior would be to select the same file archive.org does. This will typically be the 512kb mp4 file.

Therefore we will try to get that file first, then default to some other mp4, ogv or mov file.