Streaming server: Difference between revisions

Revision as of 19:03, 26 April 2006

Revision as of 23:33, 3 May 2006

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Packet Streaming

Packet streaming requires specialized server side software to serve data to a "source." The source may be live (such as a microphone connected to a computer) or in file form. When a request is made, server-side software "feeds" the data to a connected client in small "chuncks" known as packets. Usually, the specialized server software uses a proprietry protocol to negotiate the transfer of each packet so that both the client and the server have an understanding of how the stream is progressing with regard to whether or not the stream has been interuptedinterrupted. After a client receives and reads an incoming packet, the packet is discarded.

From a client side prospective, one might be familiar with the term "buffering" or "negotiating." For example, if you connect to a live radio broadcast through iTunes (client), there is usually a breifbrief period or time between initiating the connection and when the audio starts to play. It is during this time that iTunes is negotiating with the server to connect to a stream. At times the audio may stop, or seem to skip. During these periods of silence, there is a re-negotiation of the connection, usually due to high network traffic, where the server and client must re-negotiate the connection in order to ensure that no packets are dropped or reduce the connection speed to accomodateaccommodate the high network traffic by establishing a new, lower bandwidth connection.

Progressive Streaming

Progressive streaming is traditionally how most web servers "serve" files, web pages and images. Where the "source" is a file residing on the server. When a request for a file is made, the server transfers the file to the client. The file is not transferedtransferred all in one huge "chunk," but is moved across the network using standard intenet-based protocols to negotiate when the file transfer is complete. Once the transfer is complete, the entire file is stored on the clients system.

From a client side perspective, one might be familiar with downloading a large JPG image with a browser, such as FireFox (client). Some web browsers will actually start to render the image in the browser window from the top down before the entire file is received. In reality, the browser (client) is recievingreceiving and presenting the incoming data as soon as possible -- even though the entire image has not been transferedtransferred, the browser can still present portions of the data as the data is being recievedreceived.

For audio or video it means that audio or video will be played back as soon as the data is received on the end user's system/software even though the entire audio or video file has not yet been transferedtransferred.

A good example of a progressive streaming approach is used by the folks as Wimpy Player. The Wimpy tools all rely on the progressive streaming approach to serve and play audio and video files within a web page.