ACTIONSCRIPT 3 Developer’s Guide en

Chapter 25: Working with video
Flash Player 9 and later, Adobe AIR 1.0 and later
Flash video is one of the standout technologies on the Internet. However, the traditional presentation of video—in a
rectangular screen with a progress bar and control buttons underneath—is only one possible use of video. Through
ActionScript, you have fine-tuned access to and control over video loading, presentation, and playback.
Basics of video
Flash Player 9 and later, Adobe AIR 1.0 and later
One important capability of Adobe® Flash® Player and Adobe® AIR is the ability to display and manipulate video
information with ActionScript in the same way that you can manipulate other visual content such as images,
animation, text, and so on. When you create a Flash Video (FLV) file in Adobe Flash CS4 Professional, you have the
option to select a skin that includes common playback controls. However, there is no reason you need to limit yourself
to the options available. Using ActionScript, you have fine-tuned control over loading, displaying, and playback of
video—meaning you could create your own video player skin, or use your video in any less traditional way that you
want. Working with video in ActionScript involves working with a combination of several classes:
Video class: The classic video content box on the Stage is an instance of the Video class. The Video class is a display
object, so it can be manipulated using the same techniques that can be applied to other display objects, such as
positioning, applying transformations, applying filters and blending modes, and so forth.
StageVideo class: The Video class typically uses software decoding and rendering. When GPU hardware
acceleration is available on a device, your application can take best advantage of hardware accelerated presentation
by switching to the StageVideo class. The StageVideo API includes a set of events that tell your code when to switch
between StageVideo and Video objects. Stage video imposes some minor restrictions on video playback. If your
application accepts those limitations, implement the StageVideo API. See “Guidelines and limitations” on page 513.
NetStream class: When you’re loading a video file to be controlled by ActionScript, a NetStream instance represents
the source of the video content—in this case, a stream of video data. Using a NetStream instance also involves using
a NetConnection object, which is the connection to the video file—like the tunnel that the video data is fed through.
Camera class: When you’re working with video data from a camera connected to the user’s computer, a Camera
instance represents the source of the video content—the user’s camera and the video data it makes available.
When you’re loading external video, you can load the file from a standard web server for progressive download, or you
can work with streaming video delivered by a specialized server such as Adobe’s Flash® Media Server.
Important concepts and terms
Cue point A marker that can be placed at a specific moment in time in a video file, for example to act like a bookmark
for locating that point in time, or to provide additional data that is associated with that moment in time.
Encoding The process of taking video data in one format and converting it to another video data format; for example,
taking a high-resolution source video and converting it to a format that’s suitable for Internet delivery.
Frame A single segment of video information; each frame is like a still image representing a snapshot of a moment in
time. By playing frames in sequence at high speed, the illusion of motion is created.
Last updated 6/6/2012
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