Friday, July 25, 2008

Streaming Versus Progressive Download

Streaming Versus Progressive Download :
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There are trade-offs to consider when deciding whether to deliver a movie using progressive download, streaming, or broadcasting.
All QuickTime media types can be delivered as progressive downloads. Streaming is limited to sound, video, and text. Broadcasting is further limited to compression schemes and quality settings compatible with real-time capture and compression.
Progressive download works even when the bandwidth is not sufficient for real-time playback; it simply buffers incoming data and delivers delayed playback. Streaming and broadcasting are bandwidth limited; if the connection is not fast enough, the movie cannot play.
Streaming movies do not store a copy of the movie on the client computer, making them inherently more difficult to copy without the consent of the movie’s owner. This can be an important consideration, and is one reason why people choose streaming over progressive download.
Streams take up a specified amount of bandwidth, whereas HTTP file downloads proceed as quickly as the connection allows. It is therefore easier to manage the bandwidth usage of a streaming server than of a web server delivering progressive-download movies.
Broadcasting allows you to deliver coverage of live events as they happen, or to provide real time "chat" between computers.
To sum up, if your movie includes live coverage, you must use broadcasting. If bandwidth management and copy discouragement are paramount considerations, streaming may be your best choice for stored content. If simplicity, reliability, or quality regardless of connection speed are most important to you, progressive download is probably best.

Ref:
http://developer.apple.com/documentation/QuickTime/RM/Fundamentals/QTOverview/QTOverview_Document/chapter_1000_section_6.html

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