Phonon VideoWidget inside QGraphicsView crashes on Mac OS X (Cocoa build)

When using the Cocoa (64-bit) build of Qt on Mac OS X, placing a Phonon::VideoWidget inside a QGraphicsView causes the Phonon Quicktime backend to crash.

(Video Widgets inside QGraphicsViews seem to be very desirable, so that you can do composition and draw graphics and widgets on top of videos... as seen in this example: http://labs.qt.nokia.com/2008/11/28/videos-get-pimped/ )

The crash is always inside Phonon::QT7::VideoFrame::drawQImage().

I've attached a minimal program to reproduce the bug. Before running, you'll need to place the test movie (testMovie.m4v) into the same folder as the compiled application bundle (PhononGraphicsViewBugDemo.app), or use any other video file you have handy.

The crash seems to be a threading bug, so it doesn't happen immediately... For me, it usually happens a random number of seconds (usually 15 or less) after video starts playing.

The crash happens regardless of whether a QGLWidget is used for the GraphicsView viewport or not. (It seems that the QImage-based rendering functions are used in both cases, even when a GL context is available... As an unrelated feature request, it would be nice to have OpenGL acceleration on Mac OS X for videos in GraphicsViews, especially once QtQuick/QML gains popularity.)

Attempted workarounds
========================
I attempted to compile the phonon-vlc backend (https://projects.kde.org/projects/kdesupport/phonon/phonon-vlc ) for Mac OS X as a work-around, but I wasn't able to get it to build. I also don't know how to specify an alternate backend for Phonon on OS X... It seems to use the Quicktime backend automatically.

Stack trace:
=============

0 objc_msgSend 0 0x7fff8361733c
1 imageProviderCopyImageBlockSet 0 0x7fff8236b60b
2 imageProvider_getBytes 0 0x7fff88071959
3 -[NSBitmapImageRep _fromCGImage:performBlockUsingMutableData:] 0 0x7fff807a7a71
4 __-[NSBitmapImageRep _withoutChangingBackingPerformBlockUsingBackingMutableData:]_block_invoke_1 0 0x7fff8076c949
5 -[NSBitmapImageRep _performBlockUsingBacking:] 0 0x7fff8069855a
6 -[NSBitmapImageRep _withoutChangingBackingPerformBlockUsingBackingMutableData:] 0 0x7fff8076c7f0
7 __-[NSBitmapImageRep _performBlockUsingBackingMutableData:]_block_invoke_1 0 0x7fff8076c786
8 -[NSBitmapImageRep _performBlockUsingBacking:] 0 0x7fff8069855a
9 -[NSBitmapImageRep _performBlockUsingBackingMutableData:] 0 0x7fff8076c705
10 -[NSBitmapImageRep getBitmapDataPlanes:] 0 0x7fff8076c6b3
11 -[NSBitmapImageRep bitmapData] 0 0x7fff8076c65e
12 Phonon::QT7::VideoFrame::drawQImage 0 0x10176e9e7
13 Phonon::QT7::VideoRenderWidget::event 0 0x10177a6bd
14 QApplicationPrivate::notify_helper 0 0x1000fdb0d
15 QApplication::notify 0 0x10010396d
16 QCoreApplication::notifyInternal 0 0x100d4c7ac
17 QWidgetPrivate::drawWidget 0 0x1001552c2
18 QWidgetPrivate::paintSiblingsRecursive 0 0x100155ed6
19 QWidgetPrivate::drawWidget 0 0x1001550f0
20 QWidgetPrivate::paintSiblingsRecursive 0 0x100155ed6
21 QWidgetPrivate::drawWidget 0 0x1001550f0
22 QWidgetPrivate::render 0 0x100156538
23 QWidget::render 0 0x10015673e
24 QWidgetPrivate::render_helper 0 0x100156b5b
25 QWidget::render 0 0x100156d24
26 QGraphicsProxyWidget::paint 0 0x1006c3a67
27 _q_paintItem 0 0x1006c7f84
28 QGraphicsScenePrivate::drawItemHelper 0 0x1006d01b8
29 QGraphicsScenePrivate::draw 0 0x1006d32d2
30 QGraphicsScenePrivate::drawSubtreeRecursive 0 0x1006d3eb2
31 QGraphicsScenePrivate::drawItems 0 0x1006d4943
32 QGraphicsView::paintEvent 0 0x1006fa7e3
33 QWidget::event 0 0x100157806
34 QFrame::event 0 0x1004cb27c
35 QAbstractScrollArea::viewportEvent 0 0x1005568c7
36 QGraphicsView::viewportEvent 0 0x1006fcfdb
37 QAbstractScrollAreaFilter::eventFilter 0 0x100558da0
38 QCoreApplicationPrivate::sendThroughObjectEventFilters 0 0x100e39437
39 QApplicationPrivate::notify_helper 0 0x1000fdade
40 QApplication::notify 0 0x10010396d
41 QCoreApplication::notifyInternal 0 0x100d4c7ac
42 qt_sendSpontaneousEvent 0 0x1000fdccc
43 -[QCocoaView drawRect:] 0 0x1000a702d
44 -[NSView _drawRect:clip:] 0 0x7fff8078ac49
45 -[NSView _recursiveDisplayAllDirtyWithLockFocus:visRect:] 0 0x7fff807898bc
46 -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] 0 0x7fff80787f8e
47 -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] 0 0x7fff80788e5a
48 -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] 0 0x7fff80788e5a
49 -[NSView _displayRectIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:] 0 0x7fff80784362
50 -[NSView displayIfNeeded] 0 0x7fff806fdb9a
51 QGraphicsScenePrivate::_q_processDirtyItems 0 0x1006df6e4
52 QGraphicsScene::qt_metacall 0 0x1006e02ef
53 QObject::event 0 0x100e470d9
54 QGraphicsScene::event 0 0x1006e4325
55 QApplicationPrivate::notify_helper 0 0x1000fdb0d
56 QApplication::notify 0 0x10010403e
57 QCoreApplication::notifyInternal 0 0x100d4c7ac
58 QCoreApplicationPrivate::sendPostedEvents 0 0x100e3a18b
59 __CFRunLoopDoSources0 0 0x7fff82cc2401
60 __CFRunLoopRun 0 0x7fff82cc05f9
61 CFRunLoopRunSpecific 0 0x7fff82cbfdbf
62 RunCurrentEventLoopInMode 0 0x7fff8674791a
63 ReceiveNextEventCommon 0 0x7fff8674771f
64 BlockUntilNextEventMatchingListInMode 0 0x7fff867475d8
65 _DPSNextEvent 0 0x7fff806cde64
66 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] 0 0x7fff806cd7a9
67 -[NSApplication run] 0 0x7fff8069348b
68 QEventDispatcherMac::processEvents 0 0x1000b8d54
69 QEventLoop::processEvents 0 0x100e38af4
70 QEventLoop::exec 0 0x100e38e14
71 QCoreApplication::exec 0 0x100e3a43c
72 main main.cpp 22 0x1000034ed