Efficiently detect if a device will play silent videos that have the autoplay attribute

问题:

With Chrome 53 and iOS 10 both out now, there are now Android and iOS devices that are capable of automatically playing videos that are silent and have the autoplay attribute. I'd like to know how to detect this with JavaScript.

For Chrome 53, the <video> must have the autoplay and muted attributes (yes, the muted attribute is required even if the video file doesn't have any audio tracks).

For iOS 10, the <video> must have the autoplay attribute and, for non-iPad iOS 10 devices, the playsinline attribute too (yes, it must be playsinline; webkit-playsinline won't work).

So a <video> will automatically play in both Chrome 53 and iOS 10 (including non-iPad iOS 10 devices) if it has all three attributes: autoplay, muted, and playsinline.

If I were just interested in detecting this on iOS 10 devices, the code would be quite simple. I'm using jQuery, but this could easily be converted into vanilla JavaScript:

var muted_videos_autoplay = false;  $('<video playsinline>').on('play', function() {   muted_videos_autoplay = true; })[0].play();  setTimeout(function() {   alert('muted_videos_autoplay: ' + muted_videos_autoplay); }, 300); 

But on Chrome 53, the only way I've found to do it is quite complicated:

var muted_videos_autoplay = false;  $('<video autoplay muted style="position: fixed; top: 0; opacity: 0; pointer-events: none;" src="data:video/mp4;base64, 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MTAw">').on('play', function() {   muted_videos_autoplay = true;   $(this).remove(); }).appendTo('body');  setTimeout(function() {   alert('muted_videos_autoplay: ' + muted_videos_autoplay); }, 300); 

For the record, I got the video source from here.

I could make the Chrome 53 code work for all iOS 10 devices too simply by adding the playsinline attribute onto the <video> that gets appended to the <body>. But I'd like to find a more efficient way to detect this behavior, if possible. Does anybody know of one?

回答1:

You can detect video autoplay support by checking if the paused status of a video element changes after it programmatically plays. This alone can return false negatives in some mobile browsers, so a Promise check should be added in order to cover these.

This method works in all major browsers (desktop and mobile), except for Android <= 4.0 and Windows Phone, where it returns a false negative.

Here is the detect function:

var supports_video_autoplay = function(callback) {    if (typeof callback !== "function") return false;    var v = document.createElement("video");   v.paused = true;   var p = "play" in v && v.play();    callback(!v.paused || ("Promise" in window && p instanceof Promise));  }; 

Usage:

supports_video_autoplay(function(supported) {   if (supported) {     // video autoplay supported!   } else {     // no video autoplay support :(   } }); 

Live test: https://codepen.io/paulorely/pen/QveEGy

文章来源: Efficiently detect if a device will play silent videos that have the autoplay attribute