Bug 53325 – [Qt] canvas.drawImage(HTMLVideoElement) doesn't work with Qt Multimedia backend

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

[Kalle Vahlman]

Currently, the 2D canvas API call drawImage() with an video element fails to render the video frame to the canvas with the Qt Multimedia backend.

The drawImage() call eventually ends up calling MediaPlayerPrivate::paintCurrentFrameInContext() which simply delegates to paint().

There seems to be two issues with this:

 - When AC is enabled, the paint() call is a no-op, thus the rendering never happens.
 - Even without AC, rendering the scene to the context painter doesn't work (not sure why this is).

A simple solution for this is to reimplement the paintCurrentFrameInContext() and paint the QGraphicsVideoItem directly, so the video scene state doesn't affect the rendering (I suppose that's the problem currently).

Patch incoming.

[Kalle Vahlman]

Created attachment 80485 [details]
Patch to fix drawImage(HTMLVideoElement) for Qt Multimedia

[Benjamin Poulain]

Please follow http://trac.webkit.org/wiki/QtWebKitBugs when reporing bug here (missing Qt keyworkd).

[Eric Seidel (no email)]

Looks sane to me, but a Qt person shoudl really look.

[Andreas Kling]

Comment on attachment 80485 [details]
Patch to fix drawImage(HTMLVideoElement) for Qt Multimedia

Kool fix! r=me

[WebKit Commit Bot]

Comment on attachment 80485 [details]
Patch to fix drawImage(HTMLVideoElement) for Qt Multimedia

Clearing flags on attachment: 80485

Committed r77207: <http://trac.webkit.org/changeset/77207>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.

[Benjamin Poulain]

Nice work. How http://www.craftymind.com/factory/html5video/CanvasVideo.html looks with the patch? :)