Working in full-screen mode with hardware acceleration

This section explores the way full-screen mode works and discusses the changes that occur once you install Flash Player 9 Update 3.

Assuming that Flash Player 9 Update 3 has been applied, the prerequisites are met, and the FLVPlayback.fullScreenTakeOver property is set to true, which is the default setting, Flash Player uses hardware acceleration to scale the video file, rather than scaling it through software.

If the FLVPlayback component runs in an earlier version of Flash Player—or if the prerequisites for hardware acceleration are not met—Flash Player scales up the video itself. This is the primary difference, as all versions prior to Flash Player 9 rely on Flash Player for full-screen mode scaling.

To take advantage of hardware acceleration for full-screen support, your computer must have a DirectX 7–compatible video card with 4 MB or more of VRAM (video RAM). This hardware support is available in Windows 2000 or Mac OS X 10.2, and later versions of these operating systems. DirectX provides APIs that serve as an interface between software and the video hardware to accelerate three-dimensional and two-dimensional graphics, among other things.

To take advantage of hardware acceleration mode, you must invoke full-screen mode in one of the following ways:

• Using the full-screen toggle button on an FLVPlayback skin
• Using the FullScreenButton video control
• Using the FLVPlayback.enterFullScreenDisplayState() method

Note: If you invoke full-screen mode by setting the Stage.displayState property to StageDisplayState.FULLSCREEN, FLVPlayback does not use hardware acceleration, even if the video hardware and memory are available on the system.

Handling skin distortion

One consequence of using hardware acceleration for full-screen mode is that the FLVPlayback component's skins are scaled along with the video player and the FLV file. The following image shows the result of using full-screen mode on a 15-inch monitor at a resolution of 1280 x 1024 with a video file that has a width of 320 pixels and a height of 240 pixels, the default FLVPlayback component's dimensions (see Figure 1).

Figure 1. FLVPlayback component skin scaled for full-screen mode using hardware acceleration

The distortion effect of the scaled skin is more pronounced on FLV files with smaller dimensions or when FLV files are viewed on a larger monitor. Conversely, the distortion effect is less pronounced on larger FLV files or when the video is viewed on smaller monitors. For example, changing from 640 x 480 to 1600 x 1200 still increases the size of the skin but distorts the skin less.

The FLVPlayback component includes the skinScaleMaximum property, which enables you to limit the scaling of the FLVPlayback skin when hardware acceleration is used. You may choose to limit the scaling based on the specific content that is being scaled and your aesthetic tastes regarding the appearance of large skins. Limiting the scaling of the skin, however, requires a combination of hardware and software to scale the video. In some cases, limiting the scaling of the skin can adversely affect performance on videos with large dimensions that are encoded at a high bit rate. If the video is large (640 pixels wide or more, 480 pixels tall or more, for example), you should avoid setting skinScaleMaximum to a small value—because it could cause performance problems on large display monitors. Figure 2 shows the same skin as shown in Figure 1, except before taking this screenshot the skinScaleMaximum was set to a value of 2 (see Figure 2). In this case, the FLVPlayback component rendered the video (but not the skin) at 640 x 512, a little more than twice its original size, and hardware acceleration did the remainder of the scaling (640 x 2 = 1280 and 512 x 2 = 1024) for both the video and the skin.

Figure 2. Setting the skinScaleMaximum property to specify the largest multiple used to scale up the skin of the FLVPlayback component in full-screen mode

Using the enterFullScreenDisplayState() method

You can also invoke full-screen mode with ActionScript 3.0 by calling the enterFullScreenDisplayState()method, as shown in the following code example:

function handleClick(e:MouseEvent):void {
   myFLVPlybk.enterFullScreenDisplayState();
}
myButton.addEventListener(MouseEvent.CLICK, handleClick);

In this example, full-screen mode is not invoked by clicking the full-screen toggle button on an FLVPlayback skin but, rather, by clicking an ordinary button (MyButton) on the Stage. Clicking the button triggers the handleClick event handler, which calls the enterFullScreenDisplayState() method.

The enterFullScreenDisplayState() method sets the Stage.displayState property to StageDisplayState.FULL_SCREEN, and therefore carries the same restrictions as the displayState property. Generally, this means that you must call it from an event handler for the MouseEvent.CLICK event. For more information on using the enterFullScreenDisplayState() method and the Stage.displayState property, see the online ActionScript 3.0 Language and Components Reference.

Exiting full-screen mode

To exit full-screen mode, click the full-screen button again or press the Escape key.

Setting the following properties can cause layout changes that cause the FLVPLayback component to exit full-screen mode: height, registrationHeight, registrationWidth, registrationX, registrationY, scaleX, scaleY, width, x, y. Calling the following methods also cause the FLVPlayback component to exit full-screen mode: setScale(), setSize().

If you set the align or scaleMode properties, the FLVPlayback component sets them to center and maintains the aspect ratio for the content (maintainAspectRatio) until the user exits full-screen mode.

Changing the value of the fullScreenTakeOver property from true to false when you are using full-screen mode also causes Flash to exit full-screen mode.

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