Answer 1

Rakesh Das Hi
A simple way to do it.
Is to use a HTML5 video player.
Here is a list of open Source HTML 5 video players.
https://blog.bitsrc.io/5-open-source-html5-video-players-for-2018-38fa85932afb
The documentation of the video players are provided in the link

You will need multiple source files as <DD> mentioned. The source should be in the quality you want to use.
Below is an example. With the Afterglow video player.
I use a high resolution and low resolution video src file.
Controls are enabled also with a quality attribute.

If you are not seeing the HD an SD settings try the code in a web browser.
Web link - https://code.sololearn.com/W9CfObbyphN1
App link - https://code.sololearn.com/W9CfObbyphN1/?ref=app