Here's a workaround for a bug introduced by iOS 5.0: when displaying a full-screen video from a UIWebView in a view controller within a UINavigationController, the view controller won't receive the typical willRotate / didRotate calls, and won't be querie

gistfile1.m

#define kVideoOverlayControllerClass NSClassFromString(@"MPInlineVideoViewController")

@implementation CJVideoRotationNavigationController

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    if ([self.topViewController isKindOfClass:kVideoOverlayControllerClass]) {
        NSUInteger index = [self.viewControllers indexOfObject:self.topViewController] - 1;
        
        if (index < self.viewControllers.count) {
            return [[self.viewControllers objectAtIndex:index] shouldAutorotateToInterfaceOrientation:interfaceOrientation];
        }
    }

    return [super shouldAutorotateToInterfaceOrientation:interfaceOrientation];
}

- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {    
    [super willRotateToInterfaceOrientation:toInterfaceOrientation duration:duration];
    
    if ([self.topViewController isKindOfClass:kVideoOverlayControllerClass]) {
        NSUInteger index = [self.viewControllers indexOfObject:self.topViewController] - 1;
        
        if (index < self.viewControllers.count) {
            [[self.viewControllers objectAtIndex:index] willRotateToInterfaceOrientation:toInterfaceOrientation duration:duration];
        }
    }
}

- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation {
    [super didRotateFromInterfaceOrientation:fromInterfaceOrientation];
    
    if ([self.topViewController isKindOfClass:kVideoOverlayControllerClass]) {
        NSUInteger index = [self.viewControllers indexOfObject:self.topViewController] - 1;
        
        if (index < self.viewControllers.count) {
            [[self.viewControllers objectAtIndex:index] didRotateFromInterfaceOrientation:fromInterfaceOrientation];
        }
    }
}

@end

NB: You may want to implement a check to see what the OS version is, as this is unnecessary with iOS 4 – though everything still behaves properly with this code as-is.