How can I show only a section of a video frame with CSS or JavaScript?

Question

I want to show only part of the video frame for a given video. Let me explain what I mean with examples:

1. I have a wide screen video (852 x 480) but I want to display it as a full screen video (640 x 480) by using CSS or JavaScript to imitate cropping it. The video file doesn't change; the script just hides the pixels at the sides.
2. I have a non-standard sized video that is a custom mix of two 640 x 480 video side-by-side, so it is 1280 x 480 in total size. Without having to edit the video, I would like to imitate having two videos play simultaneously on a page, but it will be from this single source video. I would like to make two video elements 640 x 480 and one focuses on the part to the left and the other focuses to the part on the right on the 1280 original video source.

I imagine setting properties like top and left to designate the start point for the video, then setting properties like bottom and right or height and width to designate how wide and high the video will will be shown from the start point.

I would very much prefer a CSS only solution. I doubt one exists however. I am okay with javascript/jquery. I have an idea based on the solution in this answer, but that seems a bit on the hack side of things. Basically, I could make a div the size that I want the video, relatively position it and set overflow to hidden. Then I would put the video element inside the div and absolutely position that so that the parts I want displayed are seen in the div, but the other parts overflow and are hidden. That does have the benefit of not needing javascript, but I would prefer to use real properties if they exists and no added HTML.

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Here's some images to show what I want to accomplish, but do not know of any non-hack solution. The white part would be the size of the video frame and what is shown to the user. The gray part is what is hidden.

Video frame is 640 x 480 starting at the top left corner. The source is 852 x 480. Video frame is 640 x 480 starting at the top right corner. The source is 852 x 480. Video frame is 640 x 480 starting at top and 106 pixels from the left. The source is 852 x 480. Video frame is 320 x 240 starting at 140 pixels from the top and 212 pixels from the left. The source is 852 x 480.

Answer 1

You can use CSS's clip-path property to display the section of the video.

You'll need to define inline svg clipPath element, add a path element with co-ordinates, give the clipPaths the ids and use them in your CSS to clip the video(clip-path: url(#id)).

Fiddle

HTML:

<iframe id="clip-1" width="852" height="480" src="//www.youtube.com/embed/nGt_JGHYEO4" frameborder="0" allowfullscreen></iframe>
<iframe id="clip-2" width="852" height="480" src="//www.youtube.com/embed/nGt_JGHYEO4" frameborder="0" allowfullscreen></iframe>
<iframe id="clip-3" width="852" height="480" src="//www.youtube.com/embed/nGt_JGHYEO4" frameborder="0" allowfullscreen></iframe>
<iframe id="clip-4" width="852" height="480" src="//www.youtube.com/embed/nGt_JGHYEO4" frameborder="0" allowfullscreen></iframe>

<svg>
    <defs>
        <!-- Co-ordinates for the first image in your question -->
        <clipPath id="one">
            <path d="M0,0 L640,0 L640,480 L0,480z" />
        </clipPath>
        <!-- Co-ordinates for the second image in your question -->
        <clipPath id="two">
            <path d="M212,0 L852,0 L852,480 L212,480z" />
        </clipPath>
        <!-- Co-ordinates for the third image in your question -->
        <clipPath id="three">
            <path d="M106,0 746,0 746,480 106,480z" />
        </clipPath>
        <!-- Co-ordinates for the fourth image in your question -->
        <clipPath id="four">
            <path d="M212,140 532,140 532,380 212,380z" />
        </clipPath>
    </defs>
</svg>

CSS:

#clip-1 {
    position: absolute;
    -webkit-clip-path: url(#one);
    clip-path: url(#one);
}
#clip-2 {
    position: absolute;
    top: 480px;
    -webkit-clip-path: url(#two);
    clip-path: url(#two);
}
#clip-3 {
    position: absolute;
    top: 960px;
    -webkit-clip-path: url(#three);
    clip-path: url(#three);
}
#clip-4 {
    position: absolute;
    top: 1440px;
    -webkit-clip-path: url(#four);
    clip-path: url(#four);
}
body {
    margin: 0 auto;
}