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…w-posts New User Experience and Enhancement posts.
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,225 @@ | ||
| --- | ||
| title: Autoplay | ||
| description: | | ||
| Learn how to start video playback automatically and employ autoplay strategies that don't lead to degraded user experience. | ||
| date: Septembed 22nd, 2021 | ||
| length: '1:04' | ||
| video-sources: | ||
| - src: https://storage.googleapis.com/kino-assets/autoplay/manifest.mpd | ||
| type: application/dash+xml | ||
| - src: https://storage.googleapis.com/kino-assets/autoplay/master.m3u8 | ||
| type: application/x-mpegURL | ||
| video-subtitles: | ||
| - default: true | ||
| kind: captions | ||
| label: English | ||
| src: https://storage.googleapis.com/kino-assets/autoplay/cap-en.vtt | ||
| srclang: en | ||
| - default: false | ||
| kind: captions | ||
| label: Česky | ||
| src: https://storage.googleapis.com/kino-assets/autoplay/cap-cs.vtt | ||
| srclang: cz | ||
| thumbnail: https://storage.googleapis.com/kino-assets/autoplay/thumbnail.png | ||
| media-session-artwork: | ||
| - sizes: 96x96 | ||
| src: https://storage.googleapis.com/kino-assets/autoplay/artwork-96x96.png | ||
| type: image/png | ||
| - sizes: 128x128 | ||
| src: https://storage.googleapis.com/kino-assets/autoplay/artwork-128x128.png | ||
| type: image/png | ||
| - sizes: 192x192 | ||
| src: https://storage.googleapis.com/kino-assets/autoplay/artwork-192x192.png | ||
| type: image/png | ||
| - sizes: 256x256 | ||
| src: https://storage.googleapis.com/kino-assets/autoplay/artwork-256x256.png | ||
| type: image/png | ||
| - sizes: 384x384 | ||
| src: https://storage.googleapis.com/kino-assets/autoplay/artwork-384x384.png | ||
| type: image/png | ||
| - sizes: 512x512 | ||
| src: https://storage.googleapis.com/kino-assets/autoplay/artwork-512x512.png | ||
| type: image/png | ||
| autoplay: true | ||
| --- | ||
|
|
||
| ## Introduction | ||
|
|
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| Sometimes the video is not just a _part_ of your web page content. Sometimes it | ||
| is _the_ content and your users expect it to start playing automatically | ||
| as soon as possible. | ||
|
|
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| There are two main ways of accomplishing this autoplay behavior: | ||
|
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| 1. Using the `<video autoplay>` attribute. | ||
| 2. Using JavaScript. | ||
|
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| Let's take a look at the benefits and limitations of each. | ||
|
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||
| ## Using the `autoplay` attribute | ||
|
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| The better known and simpler way of instructing browsers to automatically play | ||
| a video is using the `autoplay` attribute. | ||
|
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||
| ```html | ||
| <video controls autoplay> | ||
| <source src="video.mp4" type="video/mp4"> | ||
| </video> | ||
| ``` | ||
|
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||
| Browsers might not honor the attribute for various reasons, likely | ||
| because a given video contains sound. Automatic playback of videos with sound often leads | ||
| to poor user experience and browsers use multiple signals to determine | ||
| if playback with sound should be allowed. | ||
|
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| To improve the chance of browsers starting playback, choose to | ||
| play the video muted. | ||
|
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||
| ```html | ||
| <!-- Browsers will usually allow autoplay when | ||
| the `muted` attribute is also present. --> | ||
| <video controls autoplay muted> | ||
| <source src="video.mp4" type="video/mp4"> | ||
| </video> | ||
| ``` | ||
|
|
||
| **Note:** Unless you provide your own UI for the video controls, make sure | ||
| to also use the `controls` attribute to let the browser render the default video | ||
| controls. | ||
|
|
||
| ## Using JavaScript | ||
|
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| In JavaScript the `<video>` element contains a `play()` method that can be used | ||
| to attempt to manually start playback as soon as possible. | ||
|
|
||
| ```html | ||
| <video controls> | ||
| <source src="video.mp4" type="video/mp4"> | ||
| </video> | ||
| <script> | ||
| const videoElement = document.querySelector('video'); | ||
| videoElement.play().then(() => { /* video is playing */}); | ||
| </script> | ||
| ``` | ||
|
|
||
| As with the `autoplay` attribute, browsers may choose to not play the | ||
| video in this situation, especially if it contains sound and is not muted. | ||
|
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| One benefit of calling the `play()` method is that it returns a promise | ||
| that resolves when playback starts and rejects when it won't start for any | ||
| reason. This gives you a chance to respond. | ||
|
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| A good strategy is to mute the video and re-attempt the playback. If | ||
| that fails, render a custom play button or don't do anything and let the user use video controls rendered by the browser. | ||
|
|
||
| ```html | ||
| <video controls> | ||
| <source src="video.mp4" type="video/mp4"> | ||
| </video> | ||
| <script> | ||
| const videoElement = document.querySelector('video'); | ||
| videoElement.play() | ||
| .catch(() => { | ||
| // Mute video and retry playback. | ||
| videoElement.muted = true; | ||
| videoElement.play() | ||
| .catch(() => { | ||
| // Can't autoplay with sound or muted. | ||
| }) | ||
| }) | ||
| /** | ||
| * Note: In older browsers the `play()` method may not | ||
| * return a promise. If you need to support | ||
| * pre-2019 browsers, you could do: | ||
| * | ||
| * Promise.resolve(videoElement.play()) | ||
| * .catch(() => { | ||
| * // Mute and try playing again. | ||
| * }) | ||
| * | ||
| * ... to wrap the non-promise return values as promises. | ||
| </script> | ||
| ``` | ||
|
|
||
| ### Unmute button | ||
|
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| Refresh this page and you'll likely notice the video now plays muted and there | ||
| is a "Tap to unmute" button rendered over it. | ||
|
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| That's a custom element styled and positioned to render over the video. When | ||
| the button is clicked, simple JavaScript runs and removes the `muted` attribute | ||
| from the video and it continues playing with sound. | ||
|
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| This strategy combines the best of both worlds. Users are not going to get | ||
| startled by sudden loud playback while the action necessary to achieve playback | ||
| with sound is handily available. | ||
|
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| ```html | ||
| <section> | ||
| <video controls> | ||
| <source src="video.mp4" type="video/mp4"> | ||
| </video> | ||
| <button>🔊</button> | ||
| </section> | ||
|
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||
| <style> | ||
| /* Only basic layout, no fancy styling. */ | ||
| section { | ||
| display: inline-block; | ||
| position: relative; | ||
| } | ||
| button { | ||
| font-size: 80px; | ||
| position: absolute; | ||
| top: 50%; | ||
| left: 50%; | ||
| transform: translate(-50%, -50%); | ||
| } | ||
| </style> | ||
|
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||
| <script> | ||
| const videoElement = document.querySelector('video'); | ||
| const unmuteButton = document.querySelector('button'); | ||
| videoElement.play() | ||
| .catch(() => { | ||
| // Mute video and retry playback. | ||
| videoElement.muted = true; | ||
| videoElement.play() | ||
| .then(() => { | ||
| // When the unmute button is clicked, | ||
| // unmute video and remove the button. | ||
| unmuteButton.addEventListener('click', () => { | ||
| videoElement.muted = false; | ||
| unmuteButton.remove(); | ||
| }); | ||
| }) | ||
| .catch(() => { | ||
| // Can't autoplay with sound or muted. | ||
| }) | ||
| }) | ||
| </script> | ||
| ``` | ||
|
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| ## Engagement signals | ||
|
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| Browsers use various heuristics to determine whether automatic playback with | ||
| sound is expected by the user or not. These heuristics differ between browsers, | ||
| but here are a few example use cases where autoplay with sound is likely: | ||
|
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| * When the newly loaded page is a result of internal navigation initiated by | ||
| the user, e.g. click, tap etc. | ||
| * When the user has installed the PWA or added the site to their home screen. | ||
| * When user engagement signals are strong, e.g. on video sites where the user | ||
| regularly watches the content. | ||
|
|
||
| Find more in-depth information at the [Chrome Developers website]. | ||
|
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| ## What's Next? | ||
|
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| In the [next article], we are going explore the Picture-in-Picture API, which can be used to play videos and other media sources in a floating window that stays on top of other applications. | ||
|
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| [Chrome Developers website]: https://developer.chrome.com/blog/autoplay/ | ||
| [next article]: /picture-in-picture/ |
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