Flash Video Options

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 limitations. 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 downloaded. The Player cannot seek ahead to sections of the video that have not been downloaded from the web server.

Although video starts playing immediately with progressive download, this approach doesn't support live video nor does it support all the features of FlashCom such as total control over seeking. Another limitation is that the entire video is downloaded to the user 's cache, which is undesirable when dealing with copyrighted material.

The new Macromedia Video Kit is a utility for Dreamweaver developers that includes Squeeze Lite to compress video in FLV format. The utility allows HTML developers to easily embed Flash video in a web page by automatically creating the .swf file to play the video without the need for the Flash authoring environment. The Flash video plays using progressive download, as can also be accomplished using Flash MX 2004 or Flash Pro. For full details, see:

http://www.macromedia.com/software/studio/flashvideokit

For streaming video from Dreamweaver, see the Flash Video Streaming Service Lite as described at:

http://www.macromedia.com/software/flashcom/fvss
http://www.macromedia.com/devnet/mx/flash/articles/video_primer_04.html#authordwfl

Streaming Video with FlashCom

Unlike embedded video and progressive download, a Flash movie can ask the FlashCom Server to stream any part of a prerecorded video at any time. FlashCom will locate the video file, find the part of the video to send, and start streaming from that point. Whenever it is important to be able to quickly seek to any portion of a large video file, FlashCom provides an important advantage over progressive download and embedded video.

FlashCom also makes it possible to seamlessly adapt to each client's bandwidth. You can script a bandwidth test that will estimate the bandwidth available to the client and then select an appropriate size video to stream. See Chapter 17 for more on bandwidth detection.

Macromedia maintains a video section on its DevNet site:

http://www.macromedia.com/devnet/mx/flash/video.html

Macromedia has also published a video primer that provides a good summary comparing different ways to deliver prerecorded video using Flash:

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

FlashCom offers a persistent connection, allowing you to implement many features with streaming not supported by progressive download. It also offers the most robust and consistent delivery platform, especially for large videos and large numbers of users. Most notably, FlashCom streaming video allows you to:

  • Deliver live video and audio, whether from a web cam or digital video camera

  • Enable multiuser video conferencing and similar applications

  • Start video playing as soon as possible

  • Implement bandwidth detection to optimize video serving

  • Monitor quality of service and provide logging, tracking, and reporting statistics

  • Maintain full scripting control of streams for detailed interactive control of the video experience

  • Easily change content by updating external videos (this also applies to progressive download)

  • Use less client memory and disk space (especially true for large videos)

  • Minimize the network load because only the portion of the video that is viewed needs to be downloaded

  • Securely deliver copyrighted material without its being saved to the user's cache

See also Chapter 5 and Chapter 7 in this book for details on streaming.



Programming Flash Communication Server
Programming Flash Communication Server
ISBN: 0596005040
EAN: 2147483647
Year: 2003
Pages: 203

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