Embeding youtube video into post - Video's Height is not responsive

This dude talks about the EXACT thing your talking about --
Making Embedded YouTube Videos Responsive - Responsive Web Design

Any easiest way to solve this problem?
I watched the tutorial that you gave me, but that's mean that I have to add:
<div class="video-container></div> to each of my embeded video.

Look for some J$ on the web using the wrap() method. If you only use <iframe> for YouTube Embeds, than consider wrapping all <iframe> with <div class="video-container">

I'm afraid the only way to make responsive videos is to wrap them in that div.

There's more info on some of the solutions here: https://css-tricks.com/NetMag/FluidWidthVideo/Article-FluidWidthVideo.php

Other option if you don't want use jQuery to add the container is put de next code in the functions.php:

add_filter( 'embed_oembed_html', 'arj_oembed_filter', 10, 4 ) ;
function arj_oembed_filter($html, $url, $attr, $post_ID) {
    if( is_singular( 'post' ) ){
        if ( strstr( $html,'youtube.com/embed/' ) ) {
            $return = '<div class="video-container">'.$html.'</div>';
            return $return;
        }
    }
}

You could always use a plugin such as ARVE Advanced Responsive Video Embedder.

Once installed and activated you don't need to do anything except paste the video URL. I've used it with YouTube, Vimeo, and Facebook videos.

I don't know how difficult it would be to integrate something like that into a future version of GP, but with so many people now using video it feels like a must have feature.

This might also help: https://docs.generatepress.com/article/responsive-videos/