240380 2022-05-13 05:05:20 -0700 Capturing a canvas that is not in the DOM can lead to erratic frame rates or no frame emission at all 2022-05-25 20:16:10 -0700 1 1 1 Unclassified WebKit Media WebKit Nightly Build Unspecified Unspecified RESOLVED FIXED InRadar P2 Normal --- 1 youennf djg claudio.destro eric.carlson kkinnunen sabouhallawa simon.fraser webkit-bug-importer oldest_to_newest 1868726 0 youennf 2022-05-13 05:05:20 -0700 Capturing a canvas that is not in the DOM can lead to erratic frame rates or no frame emission at all 1868727 1 webkit-bug-importer 2022-05-13 05:05:45 -0700 <rdar://problem/93239022> 1868819 2 sabouhallawa 2022-05-13 11:49:39 -0700 Test case is https://jsfiddle.net/0b3dqxeg/ 1869588 3 claudio.destro 2022-05-16 23:10:56 -0700 Hi hope this helps: in our solution, canvas with CSS fixed position works 1869591 4 claudio.destro 2022-05-16 23:15:39 -0700 Example missing (sorry): modify the test case to: <canvas id="canvas2" style="position: fixed; bottom: 0; right: 0; width: 100px"></canvas> videos still not playing in 15.4 desktop (they show a red background and nothing else happens) 1869626 5 youennf 2022-05-17 02:39:00 -0700 I did some investigations: - CanvasCaptureMediaStreamTrack::Source::canvasChanged is correctly called each time the not-in-dom canvas is changed but it returns early due to m_canvas->renderingContext()->needsPreparationForDisplay() returning true. - Normally, the page will call updateRendering which will make the actual preparation happening, which in turn will tell CanvasCaptureMediaStreamTrack::Source to generate a frame. This is what happens when canvas is in the DOM. When canvas is not in the DOM, Page::updateRendering is not called as often and this impacts the canvas track frame rate. 1871059 6 djg 2022-05-22 21:18:37 -0700 Pull request: https://github.com/WebKit/WebKit/pull/901 1871934 7 ews-feeder 2022-05-25 20:16:07 -0700 Committed r294864 (250996@main): <https://commits.webkit.org/250996@main> Reviewed commits have been landed. Closing PR #901 and removing active labels.