How to use mp4 in uploadfield

[Tim]

Have you tried anything so far? It can be helpful if you could post some code.

Have a quick look through the following post about adding SVGs to the allowed file types:

Adding SVG to the allowed files in SS4

This one comes up quite a lot on the Slack channel, so I thought it was worth a post here as well. The below is specific to SVG files, but the same techniques apply to other extensions. The first thing to note is that, contrary to what your instinct might think, an SVG isn’t an image file. In SilverStripe, images are bitmap-style files such as jpg, gif, png, etc. and when you use them, you get all kinds of extra manipulation classes. Because of this, SVG files needs to be stored in File …

It should be a case of adding the right file extension to the File class using YML as per that example. You may also need to check the server configuration to be sure that you don’t get limited by file size.