For self-hosted videos, I think you may need to use the embed field instead and use html5 video.
Ex:
<video width="320" height="240" controls="controls">
<source src="https://www.html5rocks.com/en/tutorials/video/basics/Chrome_ImF.webm" type='video/webm; codecs="vp8, vorbis"' />
<source src="https://www.html5rocks.com/en/tutorials/video/basics/Chrome_ImF.mp4" type='video/mp4; codecs="avc1.42E01E, mp4a.40.2"' />
<source src="https://www.html5rocks.com/en/tutorials/video/basics/Chrome_ImF.ogv" type='video/ogg; codecs="theora, vorbis"' />
Your browser does not support the video tag.
</video>
(width/height doesn’t matter, it will be transformed)
So in your case, try perhaps:
<video width="320" height="240" controls="controls">
<source src="https://mydomain.com/wp-content/uploads/2013/11/My-Movie.mp4" type='video/mp4; codecs="avc1.42E01E, mp4a.40.2"' />
Your browser does not support the video tag.
</video>