I'm using the Promoted Links tiles (that open in a modal dialog) with direct links to MP4 files in an adjacent Assets library called vlog e.g:
Everything is out of the box except for some CSS to adjust the video size.
This all works beautifully in Chrome & Firefox but (surprise!) when I click a Promoted Link tile in Internet Explorer it gives me a Save As prompt for the video file.
If this is an IE setting I can't seem to find it. Any pointers would be appreciated :)
NOTE: If I go to Internet Options > Security > Local Intranet > Custom Level... and set File Download to Disable it changes the behaviour and I get a "not permitted" message instead of the Save As prompt.
NOTE: In Central Admin I've already got Browser File Handling set to Permissive.