Progressive Download
Progressive download, or "fast start" or "HTTP streaming", refers to when users are able to watch as the files are downloaded. Progressive download is often called "HTTP streaming", because standard HTTP servers can deliver files in this fashion, and no special protocols are needed. HTTP streaming uses the standard HyperText Transfer Protocol used by all Web pages. HTTP streaming works by down loading an entire movie to your hard disk. During progressive downloading the user will be able to see which part of the video has downloaded, but cannot access parts of the video that have not downloaded yet. In addition, progressive download files don't adjust during downloading to match the bandwidth of the user's connection. An example of progressive download is QuickTime's "fast start" feature.

Progressive download delivery works well with short movies that you wish to view in high quality. The quality of the movie and the data rate can be high. This is excellent for movie trailers and other short video clips. However, it does mean some delay in the viewing of the video since it must be downloaded, before it can be viewed. However, because progressive download is placed on a standard HTTP or FTP server, it is easy to administer. In addition, there aren't any issues with firewalls which are found in most schools, colleges, universities and many places of business, because progressive downloads use the same protocol as common Web content, there is less a chance of encountering problems getting past firewalls than with content from a streaming server.

Progressive download is not a good choice for long movies or material that must be broadcast live.

To view examples of progressive download click here.

Now lets look at the alternative, True Streaming.