Float an NSView above a window being used by DVDPlayback framework - macos

Question

I am trying to write a simple DVD player using Mac OS X's DVDPlayback.framework. I can get the DVD to play within a window, but ultimately I want this to run as a full-screen app.
I'm having difficulty adding a sub-view to display media controls whilst the DVD is playing (pause / play, progress slider to scroll through the movie, change chapter etc).
It seems that if I create a sub-view (NSView) within the window being used by the DVD framework, it always seems to fall behind the DVD content, even if I tell the NSView to be at the top-most level.
Here's the simplified code, which just tries to create a white sub-view within a region of the window:
(I've tried the code on 10.6 and 10.7 with the same results).
const BOOL PLAY_DVD = YES;
#interface ControlsView : NSView {
}
#end
#implementation ControlsView
- (void)drawRect:(NSRect)rect {
[[NSColor whiteColor] set];
NSRectFill(rect);
}
#end
#implementation AppDelegate
#synthesize window = _window;
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
NSView *view = self.window.contentView;
if (PLAY_DVD) {
NSLog(#"%# Playing DVD video", [self class]);
// Register error handler
OSStatus err;
err = DVDInitialize();
if (err != noErr) {
NSLog(#"DVDInitialise failed with error code %d", err);
[NSApp terminate:self];
}
// Set window to be the main window
err = DVDSetVideoWindowID([self.window windowNumber]);
// Set the display...
CGDirectDisplayID display = (CGDirectDisplayID) [[[[self.window screen] deviceDescription] valueForKey:#"NSScreenNumber"] intValue];
Boolean isSupported;
err = DVDSwitchToDisplay(display, &isSupported);
// Set video bounds
NSRect frame = [self.window frame];
CGRect rect = CGRectMake(0, 0, frame.size.width, frame.size.height);
err = DVDSetVideoCGBounds(&rect);
FSRef ref;
DVDOpenMediaFileWithURL([NSURL URLWithString:#"file:///Path/to/my/TestDVD/VIDEO_TS"]);
DVDOpenMediaFile(&ref);
DVDPlay();
}
// Attempt to add a subview to show the controls...
ControlsView *controls = [[ControlsView alloc] initWithFrame:NSMakeRect(20, 20, 100, 50)];
[view addSubview:controls positioned:NSWindowAbove relativeTo:nil];
}
#end
If PLAY_DVD is NO, the subview is correctly rendered (and I can create other sub-views and show that the ordering is correct).
If PLAY_DVD is YES, the media starts playing, but the sub-view is never visible because it always seems to fall behind the video.
The only examples of DVD playback I've been able to find have had the controls in a second window, but for a full-screen application I'd like the controls to be part of the full-screen view and to fade in/out when required.
Does anyone know how best to do this? Do my full-screen controls have to be in a separate window which floats above the full-screen window? I've not been able to find an example which has the controls and the DVD playback in the same window.
Thanks in advance for your help!