Navigator.mediaDevices.getUserMedia not working on iOS 12 Safari - ios

Question

As of iOS 12, navigator.mediaDevices.getUserMedia() is returning an error in Safari.
To recreate this, open iPhone Web Inspector, then run this snippet in the console:
var constraints = { audio: true, video: { width: 1280, height: 720 } };
navigator.mediaDevices.getUserMedia(constraints)
.then(function() {
console.log('getUserMedia completed successfully.');
})
.catch(function(error) {
console.log(error.name + ": " + error.message);
});
You'll see that this runs successfully in desktop browsers, and in iOS 11 Safari, but fails in iOS 12 Safari.
NotAllowedError: The request is not allowed by the user agent or the platform in the current context, possibly because the user denied permission.
Any idea why?
note: This is happening prior to the user being asked if their camera can be accessed, ruling out the possibility of it being because the user denied permission.

Answer 1

Setting these three attributes before calling getUserMedia solved the problem for me:
video.setAttribute('autoplay', '');
video.setAttribute('muted', '');
video.setAttribute('playsinline', '');
For some reason video.setAttribute() works but trying to assign the value directly to the video object for example video.muted = '' does not.
Also it appears that it's not necessary to call video.play().
Simply setting the video.srcObject to the stream returned by getUserMedia worked for me.
This medium post has a link to a working demo & source code.

Answer 2

There are two possible reasons for immediate NotAllowedError at the moment:
1. getUserMedia requries https
Safari seems to require https for camera and mic access, both in iOS and OSX.
With an https link, iOS Safari 12 works for me; same link in http gets NotAllowedError.
Chrome has the same requirement. This is consistent with the direction of the specification, which recently has restricted getUserMedia to secure contexts. Browsers who have yet to update, still expose navigator.mediaDevices in http, but getUserMedia always rejects with NotAllowedError.
In the future, expect browsers to remove mediaDevices entirely in http, to comply with the spec.
2. getUserMedia requires feature policy in cross-origin iframes.
This appears new with Safari 12. In iframes, getUserMedia's feature policy is off by default for cross-origin content.
This works for me:
<iframe
allow="camera;microphone"
src="https://webrtc.github.io/samples/src/content/getusermedia/gum/">
</iframe>
This doesn't work:
<iframe src="https://webrtc.github.io/samples/src/content/getusermedia/gum/">
</iframe>
...and in addition to failing with NotAllowedError, Safari warns in web console:
The top-level frame has prevented a document with a different security origin to
call getUserMedia.
This is also a recent update to the spec.

Answer 3

Turns out my particular issue was a bug in 12.01. Every device with that version had the issue, and as soon as I updated them to a newer version it went away.