Thomas Visser Colorless green ideas sleep Swiftly

Autoplaying video in WKWebView on iOS 10+

I was looking into why videos wouldn’t autoplay inside a WKWebView and couldn’t find a comprehensive up-to-date answer online. In an attempt to write such an answer I wrote this post, describing what I just learned and how I fixed the issue.

Here’s how you define a HTML video element that starts playing as soon as it comes into view, without becoming fullscreen:

<video width="320" height="240" autoplay playsinline muted>
  <source src="movie.mp4" type="video/mp4">

This is exactly the way you would implement a much more efficient GIF replacement. A great explanation of the autoplay, playsinline and muted attributes and how Safari handles them can be found in a blogpost.

The HTML snippet has the desired behavior in Mobile Safari, but when loading the same page inside a WKWebView, the video will not play. The default configuration of WKWebView is more restrictive and we need to explicitly allow this.

There’s two things we need to do:

  • Set allowsInlineMediaPlayback to true to allow media to play inline. If you don’t do this, a fullscreen player will take over the screen as soon as the video starts playing, which should be immediately.
  • Set mediaTypesRequiringUserActionForPlayback to a value that excludes video, e.g. .audio or []. If you don’t do this, the user will need to tap on the play button in the video to start it. Since we do not declare the control attribute on the video element, the play button is not visible and the video is basically unplayable.

In code, this looks as follows:

let configuration = WKWebViewConfiguration()
configuration.allowsInlineMediaPlayback = true
configuration.mediaTypesRequiringUserActionForPlayback = .audio
let webView = WKWebView(frame: .zero, configuration: configuration)

Make sure to change the configuration before passing it to WKWebView. I first tried to change the configuration through the webview (webView.configuration.allowsInlineMediaPlayback = true), but that silently failed.