After spending some time playing with video formats to work out best compatibility for desktop, tablet and phone I realised that the medialib.php may work better with a couple of minor changes.

Changes I would suggest are to raise the rank of core_media_player_html5video from 20 to 90 to give it a higher priority than core_media_player_flv, also to change the supported formats for core_media_player_flv to include mp4 and m4v.

This would mean that the mp4 alone would provide video playable by almost all devices.

Using HTML5 video it would work on Chrome, Safari and almost all mobile devices.
as a fallback it would use Flowplayer to work on Firefox and IE.

During testing I discovered that Firefox only handles stereo sound (no 6 channel surround) for ogv and webm video formats making mp4 preferable.