How to force mp4 downloads

Hello there!

Since switching to nginx/easyengine setup my mp4 files that are linked directly are no longer getting downloaded but instead opened up in the browser. How can I force nginx to download ALL (everything, because the server is used only for downloads) that is linked to ? (including mp4's)

I tried this but it didn't seem to work:
server {
location ~ \.mp4$ {
types { application/octet-stream .mp4; }
default_type application/octet-stream;
}
}

Any ideas?