Programming Flash Communication Server

This is the Title of the Book, eMatter Edition

Copyright © 2007 O’Reilly & Associates, Inc. All rights reserved.

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Preface

Flash Video Options

Whether you need FlashCom for an application requiring video depends on how you

are trying to serve your video, which depends on your application’s requirements.

For assistance in choosing the right technology based on the length of video clips,

number of viewers, and so on, see the chart at:

http://www.macromedia.com/devnet/mx/flash/articles/video_primer.html

Currently, FlashCom is the only way to collect and redistribute live

video from Flash movies as well as to stream recorded video to Flash

movies.

This book assumes you’ve made the decision to use FlashCom (whether for video or

other applications, such as chat).

However, there are other ways to play prerecorded video in Flash as described next.

For a feature comparison of FlashCom versus other Flash video alternatives, see:

http://www.macromedia.com/devnet/mx/flash/articles/video_primer_03.html

Embedded Video

Flash MX and later versions of the Flash authoring tool make it possible to import

video files directly into a Flash movie. A Flash movie containing embedded video can

be played in Flash Player 4 and later. Unfortunately, embedded video has severe limi-

tations. The video is incorporated into the .fla file before it is converted to a .swf,

meaning that the developer must republish the .swf whenever the video changes.

Furthermore, the video makes the .swf very large and slow to download. Embedded

video must be played at the same rate as the timeline and is limited to 16,000 frames.

Furthermore, sound synchronization problems occur after about 2 minutes of video

playback.

Progressive Download

Flash Player 7 added the ability to play FLV video files as they were downloaded

from a web server. The feature is usually referred to as progressive download in order

to distinguish it from streaming. All that is required to make an FLV available for

progressive download is to post it on a web server and create a Flash movie that

downloads and plays it. When a Flash movie requests an FLV file, the web server

sends the file starting from the beginning of the file until either the entire file is

downloaded or the browser and player disconnect. The file is held in cache so that

the Player can seek to different parts of the video that have already been down-

loaded. The Player cannot seek ahead to sections of the video that have not been

downloaded from the web server.