How to change video quality while keeping width and height?

Question

HTML

Hello!
The site has a video format 1920*1080.
If you choose a resolution of 360, the video on the site is reduced, but it is necessary that the dimensions remain the same, but the quality deteriorates, as is done on YouTube.
Can you please advise or point me in the right direction? )

Answer 1

Very little context. Here would be an example of your markup to see.
But I will assume that you only need to add size attributes

<video width="960" height="540">
  <source src="...">
</video>