TYPO3 Core

I use T3 4.7.12, which uses already video js for the html5 output of the videos. To make it work, I had to replace video js with the current version and add data-setup {} as well as delete mediagroup tag in the <video> tag in class.tslib_content_flowplayer.php to make it work correctly (and comment output for control-bar.js and flowplayer).

Now everything works, I only want to customize the flexform.xml so that it is not so difficult for an editor to include a video (HTML5 as standard and no tabs, otherwise the editor won’t know what to do and it will not work; I wonder why this is made so difficult?). What I would like to have now is an additional field for the chosen file to define a quality. Video JS will support this by core soon:
http://help.videojs.com/discussions/questions/1000-hd-quality-selector
http://3strandsmarketing.com/video-quality.php.
So I need an additional attribute like data-res="480" in the source tag. Please don’t leave a comment like "Use an extension for videos", I think it is better not to use an extension and instead make the media content element as good as it can be and as easy as it can be so even nearly everyone could do it without special instructions.