Video files are useful in a very limited number of situations, but should not be used for routine stacks of scrollable images (such as CT or MRI).
On this page:
Images:
When to use video
Rarely is video mandatory, but some studies do benefit from this. The reasons to use video include:
ultrasound cine clips
cardiac MRI
some dynamic barium studies
When NOT to use video
Pretty much for everything else. Certainly not for routine stacks of scrollable images such as CT or MRI but not for most ultrasound studies.
Any cases uploaded as video, unless one of the exceptions above, will not be able to be published.
Technical
At present, video support is limited and is likely to remain so in the foreseeable future. Currently, the video must be in MP4 format, H.264 encoded.
If you need to convert video, there are many transcoders available. Handbrake is an excellent free option: https://handbrake.fr/