When you visit video which have aspect ratio 21:9 https://www.youtube.com/watch?v=mlHklH5VBtI and try to share, it will generate iframe in which width is 560px and height 315px.
As I know 560x315 is 16:9 aspect ratio.
315/560 = 0.5625
9/16 = 0.5625
It should be 560x240 (21:9 aspect ratio)
240/560 = 0.428571
9/21 = 0.428571
Second problem is that youtube player is displaying some kind of blackspace above and below on 21:9 aspect ratio videos.
<iframe width="560" height="240" src="https://www.youtube.com/embed/mlHklH5VBtI" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe>
iframe {
margin: 50px 0 0 5px;
border: 10px solid red;
}
You can see blackspace between border and video. I searched through youtube iframe parameters https://developers.google.com/youtube/player_parameters but couldn't find any useful for this problem.
