Responsive Video Embedding: Embed Video Iframe Size Relative to Screen Size

The way we consume videos online has evolved dramatically, but one element remains central to the experience: embedding videos seamlessly across different devices. While modern websites focus on responsiveness, managing iframe dimensions effectively remains a challenge. Ensuring that you embed video iframes with a size relative to the screen size is crucial for creating a smooth viewing experience.

Iframes are essential for embedding external video content, such as from YouTube or Vimeo, but ensuring they adapt well to various screen sizes is no small feat. This article explores how developers can create responsive video embeds that scale effortlessly, enhancing user experience and maintaining aesthetic integrity. So let’s get started!

Understanding Iframe Basics in Video Embedding

An iframe, short for inline frame, allows developers to embed external content within a webpage. In video embedding, it enables seamless integration of videos hosted on platforms like YouTube or Vimeo. Here’s a basic example:

<iframe width="560" height="315" src="https://res.cloudinary.com/demo/video/upload/example.mp4" frameborder="0" allowfullscreen></iframe> 

While easy to implement, the default dimensions (width and height) can lead to poor viewing experiences on devices with varying screen sizes, such as smartphones or tablets. These fixed dimensions result in cropped or awkwardly scaled videos, which detract from the user experience.

The difficulty is keeping the correct aspect ratio while ensuring the iframe scales proportionately across various screen sizes. Developers need solutions for creating responsive iframes that automatically adapt to different devices.

Using CSS to Adjust Iframe Size Relative to Screen Size

Thankfully, with a few simple CSS techniques, you can embed video iframe size relative to screen size, adapting their size according to the screen and container dimensions. One of the most effective methods involves using the padding-top approach. This technique relies on a parent container to define the aspect ratio and CSS rules to adjust the iframe accordingly. Here is how you can implement it in HTML and CSS:

<div class="video-container">
  <iframe src="https://res.cloudinary.com/demo/video/upload/example.mp4" frameborder="0" allowfullscreen></iframe>
</div>
.video-container {
  position: relative;
  width: 100%;
  padding-top: 56.25%; /* 16:9 Aspect Ratio (height/width * 100) */
}

.video-container iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
} 

Here, the padding-top property defines the height as a percentage of the width, maintaining the desired aspect ratio. The iframe’s position property is set to absolute to make the iframe fit perfectly within the parent container. This approach is highly effective for ensuring the iframe scales proportionally with its container, no matter the screen size.

Another common way to adjust frame sizes is to create responsive iframes and set their dimensions in percentages. By making the iframe’s width and height relative to its parent container, it will automatically adjust as the container resizes.

<iframe src="https://www.example.com" width="100%" height="60%" frameborder="0" allowfullscreen></iframe> 

Here, setting the iframe width to 100% ensures it takes up the full width of the container. The height can be set as a percentage of the width (in this case, 60%), so it remains proportional across different screen sizes. This is a simple yet effective method for responsive iframes, especially when you want the content to scale with the container.

Another way to create responsive iframes is by using Viewport units, such as vw (viewport width) and vh (viewport height). These are incredibly powerful for creating responsive elements. They allow you to embed video iframe size relative to screen size, making it adjust seamlessly with the user’s screen. For example:

<iframe src="https://www.example.com" width="80vw" height="45vh" frameborder="0" allowfullscreen></iframe> 

In this example, the iframe width is set to 80vw, meaning it will occupy 80% of the viewport width, and the height is set to 45vh, meaning it will take up 45% of the viewport height. This method ensures that the iframe dynamically resizes with the screen, no matter the device.

Sometimes, you want the iframe to be responsive but don’t want it to exceed certain dimensions. In this case, max-width and max-height come in handy, as they limit the size of the iframe while allowing it to scale down when necessary.

<iframe src="https://www.example.com" style="width: 100%; max-width: 800px; height: auto;" frameborder="0" allowfullscreen></iframe> 

Here the iframe’s width is set to 100%, so it will take up the full width of its container. However, the max-width ensures it will never exceed 800px, keeping the iframe from becoming too large on bigger screens. The height: auto property ensures that the height adjusts proportionally based on the width, maintaining the correct aspect ratio.

HTML and JavaScript for Dynamic Resizing

Although CSS has effective responsive iframe techniques, dynamic iframe resizing based on screen width often requires JavaScript. This allows for more complex logic, such as dynamically resizing the iframe based on conditions or layout changes. Using JavaScript and the DOM, iframes can resize responsively to viewport changes. This dynamic resizing allows you to adjust the iframe’s size based on custom logic, such as changing the iframe’s dimensions when the user resizes the browser window.

To use JavaScript, let’s begin by adding an iframe tag to our HTML page:

<iframe id="dynamicIframe" src="https://www.example.com" frameborder="0" allowfullscreen></iframe> 

Next, we will create a script tag and make a function named adjustframeSize(). Inside the function we will begin by retrieving the iframe along with the width of the window:

<script>
    function adjustIframeSize() {
        const iframe = document.getElementById("dynamicIframe");
        const windowWidth = window.innerWidth;

</script> 

Next, we will use JavaScript to dynamically set the iframe’s width and height properties based on the current viewport width. For smaller screens (less than 600px), we will adjust the iframe such that it will take up 100% of the width and have a height of 300px. On medium screens (less than 1200px), the iframe width is set to 80% with a height of 500px, and for larger screens, it uses a 70% width and a 600px height.

Finally, we will call the function for an initial adjustment, and map the function to window.onresize so that the function is called whenever the window is resized. Here’s what our code looks like:

<script>
    function adjustIframeSize() {
        const iframe = document.getElementById("dynamicIframe");
        const windowWidth = window.innerWidth;

        // Adjust iframe dimensions based on screen size
        if (windowWidth < 600) {
            iframe.style.width = "100%";
            iframe.style.height = "300px";
        } else if (windowWidth < 1200) {
            iframe.style.width = "80%";
            iframe.style.height = "500px";
        } else {
            iframe.style.width = "70%";
            iframe.style.height = "600px";
        }
    }

    // Initial adjustment
    adjustIframeSize();

    // Re-adjust iframe size when the window is resized
    window.onresize = adjustIframeSize;
</script> 

Although percentage or viewport units in CSS are useful in many cases, JavaScript offers superior flexibility for more complex scenarios. Let’s take a look at some scenarios where JavaScript might be preferred over CSS-only solutions:

• Complex Conditional Logic: JavaScript is better suited for scenarios where complex conditions need to be handled, such as user interactions, specific breakpoints, or content changes. It allows for granular resizing, ensuring that the iframe adjusts dynamically based on factors like the number of items in a sidebar or external data.
• Real-Time Adjustments with Dynamic Content: Where the iframe content or surrounding elements change dynamically, JavaScript can adjust the iframe size in real-time. This is particularly useful for AJAX-loaded content, interactive maps, or videos where the iframe size needs to adapt to fit the new content.
• Custom Resizing Behavior: JavaScript enables custom animations or effects during iframe resizing, making the process smoother and more visually appealing. For example, it can animate the iframe expanding or contracting as the user resizes the window.

Using Cloudinary for Dynamic Video Sizes

Using JavaScript and CSS for video resizing might seem easy, but it’s prone to inefficiency, unnecessary complications, and errors. Fortunately, Cloudinary offers a better, more efficient solution.

Cloudinary is a cloud-based media management platform that offers a suite of tools for managing, optimizing, and transforming media files, including videos. One of its standout features is the ability to dynamically resize videos on the fly, ensuring a responsive and seamless user experience across various devices and screen sizes.

To begin using Cloudinary for dynamic video resizing, the first step is to create an account. If you don’t already have one, simply head over to the Cloudinary website and sign up for a free account. Once you’ve created your account, log in and navigate to the Assets tab. From there, click on the Upload button to upload your video to the cloud. After the upload is complete, hover over your video and click the <> button to copy the video URL. This URL will be used to link the video to your webpage, while Cloudinary will handle the resizing based on your specifications.

Now that your video is uploaded to Cloudinary, let’s move on to creating a simple HTML page to display the video. This is where Cloudinary’s dynamic video resizing features come into play.

Start by setting up the basic structure of your HTML document:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Responsive Video with Cloudinary</title>
    <style>
        /* Basic styling for the video container */
        #video-container {
            width: 100%;
            max-width: 1200px;
            margin: 0 auto;
            text-align: center;
        }
        video {
            width: 100%;
            height: auto;
            max-width: 100%;
        }
    </style>
</head>
<body>

</body>
</html> 

In this setup, we’ve defined a container #video-container for the video element. The container is styled to center the video and ensures it adjusts responsively based on the viewport’s width. The video tag is also given the necessary attributes to ensure it occupies the full width of the container, maintaining a proper aspect ratio.

Next, we’ll create a <script> tag to dynamically resize the video. Unlike traditional methods that modify iframe sizes, Cloudinary allows you to transform videos by adding transformation parameters directly to the video URL. This approach retrieves a video perfectly adjusted to your page:

<script>
        function resizeVideo() {
            const videoContainer = document.getElementById("video-container");
            const width = videoContainer.offsetWidth;

            let videoUrl = "https://res.cloudinary.com/dzte1natd/video/upload/";

            if (width < 600) {
                videoUrl += "w_400";  // Small screen size
            } else if (width < 1200) {
                videoUrl += "w_800";  // Medium screen size
            } else {
                videoUrl += "w_1200";  // Large screen size
            }

            videoUrl += "/v1736783347/myVideo.mp4";  // Replace with your Cloudinary video URL

            // Update the video source
            document.getElementById("dynamic-video").src = videoUrl;
        }

        // Call the resize function on page load and window resize
        window.onload = resizeVideo;
        window.onresize = resizeVideo;
    </script> 

Here, the resizeVideo function begins by retrieving the video container’s width and determines the appropriate Cloudinary transformation. Next, Cloudinary’s width transformations are added to the video url (w_400, w_800, w_1200) to set the video width to 400px, 800px, or 1200px, respectively, while maintaining the aspect ratio. Finally, the iframe’s src attribute is updated dynamically to reflect the selected transformation.

Now that we have the structure in place, it’s time to embed the Cloudinary video inside the HTML page. Inside the <body> tag, add a <div> container that holds your iframe:

    <div id="video-container">
        <iframe id="dynamic-video" type="text/html">
            <!-- Video will be dynamically updated here -->
        </iframe>
    </div> 

Cloudinary will automatically optimize the video based on the width of the viewport.

To see the dynamic resizing in action, save your HTML file and open it in a browser. As you resize the window, the video will adjust its size proportionally. Since Cloudinary’s platform is handling the transformations, you don’t need to worry about manual resizing with CSS or JavaScript, which simplifies the process and improves performance.

Making Video Embedding Seamless and Responsive

Responsive video iframes are key to better usability and cross-device compatibility. Developers can preserve the aspect ratio and proportional scaling of embedded videos within their containers by using techniques such as padding-top. If you are able to embed video iframes with a size relative to screen size, it significantly enhances user experience by offering consistent, aesthetically pleasing playback on any screen. Additionally, responsive iframes simplify the developer workflow by removing the need for device-specific code.

For developers seeking a robust video solution, platforms like Cloudinary offer powerful tools for managing and embedding video content with ease. With Cloudinary, you can host, optimize, and deliver videos that adapt effortlessly to various screen sizes and formats. Create an account on Cloudinary to start embedding videos seamlessly today to enhance your website’s responsiveness and deliver a superior user experience.

Learn more:

Embedding a Video Player in Next.js With Next Cloudinary

Build a Custom HTML5 Video Player With JavaScript