using grand dispatch to asynchronously load frames from a quicktime movie.

-(void)setMovie:(QTMovie *)smovie
{
	if (frameCache!=nil)
		[frameCache release];
	
	frameCache=[[NSMutableArray array] retain];
	
	QTTimeRange range=QTMakeTimeRange(QTMakeTime(0,600), [smovie duration]);
	QTMovie *copiedMovie=[[QTMovie alloc] initWithMovie:smovie timeRange:range error:nil];
	ILFrameGrabber *grabber=[[ILFrameGrabber alloc] initWithMovie:copiedMovie];
	ratio=grabber.width/grabber.height;
	NSRect screen=[[NSScreen mainScreen] frame];
	NSInteger frameCount=screen.size.width/[self bounds].size.height;
	NSInteger delta=grabber.frameCount/frameCount;
	
	dispatch_queue_t frameQueue = dispatch_queue_create( "com.interfacelab.shave.frame", NULL );
	for (int i=0; i<frameCount; i++)
		dispatch_async(frameQueue,^{
			[frameCache addObject:[grabber nsImageAtFrame:i*delta]];
			dispatch_async(dispatch_get_main_queue(), ^{
				[self setNeedsDisplay:YES];
				NSLog(@"loaded frame %d",i*delta);
			});
		});
}