ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Working with video
Keyframe A video frame which contains the full information for the frame. Other frames that follow a keyframe only
contain information about how they differ from the keyframe, rather than containing the full frame’s worth of
information.
Metadata Information about a video file that is embedded within the video file and retrieved when the video has
loaded.
Progressive download When a video file is delivered from a standard web server, the video data is loaded using
progressive download, meaning the video information loads in sequence. This has the benefit that the video can begin
playing before the entire file is downloaded; however, it prevents you from jumping ahead to a part of the video that
hasn’t loaded.
Streaming As an alternative to progressive download, a special video server can be used to deliver video over the
Internet using a technique known as streaming (sometimes called “true streaming”). With streaming, the viewer’s
computer never downloads the entire video at one time. To speed up download times, at any moment the computer
only needs a portion of the total video information. Because a special server controls the delivery of the video content,
any part of the video can be accessed at any time, rather than needing to wait for it to download before accessing it.
Understanding video formats
Flash Player 9 and later, Adobe AIR 1.0 and later
In addition to the Adobe FLV video format, Flash Player and Adobe AIR support video and audio encoded in H.264
and HE-AAC from within MPEG-4 standard file formats. These formats stream high quality video at lower bit rates.
Developers can leverage industry standard tools, including Adobe Premiere Pro and Adobe After Effects, to create and
deliver compelling video content.
Type Format Container
Video H.264 MPEG-4: MP4, M4V, F4V, 3GPP
Video Sorenson Spark FLV file
Video ON2 VP6 FLV file
Audio AAC+ / HE-AAC / AAC v1 / AAC v2 MPEG-4:MP4, M4V, F4V, 3GPP
Audio Mp3 Mp3
Audio Nellymoser FLV file
Audio Speex FLV file
More Help topics
Flash Media Server: Supported codecs
Adobe HTTP Dynamic Streaming
Encoding video for mobile devices
AIR on Android can decode a wide range of H.264 videos. However, only a small subset of H.264 videos is suited to
have a smooth playback on mobile phones. It is because many mobile phones are constrained for processing power.
Adobe Flash Player for mobile can decode H.264 videos using in-built hardware acceleration. This decoding assures
better quality at lower power consumption.
Last updated 6/6/2012
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