Bug 242679 – [macOS] Canvas.getContext('2d').drawImage on a camera video stream does not work when tab is backgrounded

• Status: RESOLVED
• Resolution: FIXED
• Component: Media

[youenn fablet]

1. Load https://jsfiddle.net/eq5upzh6/.
2. Grant prompt
3. Once the camera starts, switch to another tab and change what the camera captures.
4. Wait 6 seconds
5. Switch back to the JSFiddle tab.

One of the canvas (canvas1) stayed to a camera frame just before the switch to the other tab.
We would expect canvas1 to keep being updated even when the other tab is backgrounded.

[Radar WebKit Bug Importer]

<rdar://problem/96937033>

[youenn fablet]

This bug was externally reported.

[Anastasiya Sarmant]

The canvas stops streaming when the tab becomes inactive.

[youenn fablet]

In the jsfiddle, the video element is not playing any audio and might be paused when page goes to background.
One way to prevent it is to add a silent audio track. For instance https://jsfiddle.net/0h5edpLw/.

This raises the question of what happens to media elements which get paused as not visible+silent while they are repeatedly drawn to canvas.
In a sense, these media elements are visible so we should probably not pause them.

[youenn fablet]

Pull request: https://github.com/WebKit/WebKit/pull/2655

[EWS]

Committed 252738@main (de9dae2e5319): <https://commits.webkit.org/252738@main>

Reviewed commits have been landed. Closing PR #2655 and removing active labels.