The difference between true streaming and progressive downloading

What is the difference between Streaming and Progressive Downloading?
Do you need to purchase or license a streaming server or can I use progressive downloading via http?

True Streaming

Pros-
- More reliable connection to your media files. This is especially true if a third party hosts your files. This way your media files will not be compromised by the bandwidth available on your shared server space, whether it be commercial or free space such as that from Freeserve.
- Greater functionality. Additional features such as fast forward and rewind with files is possible which is very useful for longer files. Also multiple bandwith encoding can be achieved such as the Surestream system with Real. This means that the file you watch as an end user will be appropriate for the connection you are viewing at the time. So if someone is on a dial up modem they will view a low resolution file and if someone is on an ISDN they will view a higher resolution file. You select the target bandwidths to target when you encode. For each bandwidth you target , the larger the file size. There are limitations to the amount of bandwidths you can simultaneously encode for with the free producer product from real.
- Security. Streamed files do not get downloaded by the client and therefore they will not have a copy of the file on their machine.
- Statistics. The streaming server generates a certain level of statistics, depending on the package used in-house. This will obviously include things like file usage by time period and location.

Cons-
- Price. Whilst Real do provide a free version of their server, you still need to install it on your own co-located server. Both the Mac and Windows server are free but need a Mac or Windows 2000 server to run it on, which are both more expensive than Unix/ Linux based machines.

Progressive Downloading

Pros-
- Cost. This is free. It will run from any server. The only technical issue would be if the MIME types were not set on the server, which would be done free of charge by whoever was providing you space. Most servers come pre-configured with relevant MIME types.

Cons-
- Low reliability. As the files are not streamed the reliability of access for a user is compromised. This is true on large files, where it may be possible that it takes so long to start viewing the file that the user simply moves on after becoming impatient.
- Less functionality. The only play back features are Play, Pause and Stop, there is no Fast Forward or Rewind. You cannot encode for multiple bandwidths.
- No security. With progressive downloading, the file is actually being downloaded into a temporary directory. If the user was aware of that, they would have an unauthorised copy of the clip on their machine.
- No statistics



For more see the FAQs in Multimedia(video/sound), or visit us at http://developer.thetuckshop.com