How to embed iframe from youtube in high quality?

Question

YouTube

For example, if you insert the video in this way, it will play with auto-tuning (depending on what kind of Internet the client has, if it’s weak, then 320)

I need to immediately open the iframe video at maximum quality, well, or you can always at 720HD.
To do this, I added ?vq=720hd to the link, but for some reason this does not work.


How can I get an iframe link in hd quality. So that when the user presses the play, it will be played immediately in hd quality.

ps: I have a plyr player on my site, so the user will not be able to change the quality of the video from the site