Streaming Media

A technique for transferring data on the Internet so it can be processed as a steady and

continuous stream.

Streaming Media HistoryWhen referring to online use, the act of “streaming” is listening or viewing media in real time as it comes across the Internet.

Prior to streaming technology (pre 1993), users had to wait to completely download a media file before they could hear or view it.

Streaming Media

A stream is a real-time feed from an audio or video source, encoded in such a way that the media can begin playing steadily without making the user wait for the entire file to download to their computer.

The most popular platforms for streaming are: Real Networks RealPlayer Apple QuickTime Microsoft Media Player.

Streaming Media - Client / Server

The streaming process has 2 parts: There’s a client “player” which runs on your

computer.

Your computer connects to server containing the files to be streamed, usually via the Internet.

The server stores: the files to be streamed the technology to stream it, upon demand,

over the Internet.

Streaming Media - Client / Server

The server receives instructions from the client, it then delivers the files in a continuous stream to the client player.

Streaming is a proprietary process The player on your computer has to be the

same type as the server software that streams it so it knows how to interpret and process the stream

RealPlayer streams are different from QuickTime streams which are different from Windows Media streams

Streaming Media The same media can be stored in different forms for streaming Streamed files can be created for:

specific bandwidths specific operating systems specific resolutions (or quality)

Streaming Media PlayersRealNetworks is the leading streaming media company on the Internet. Its two main families of products are RealAudio and RealVideo. Their content can be received via RealPlayer (client).

QuickTime is Apple’s brand of multimedia and is built in to most Mac applications. The QuickTime (client) player is available for PCs. It supports multiple encoding formats, so it works with many products.

Microsoft has created its own product line of streaming media servers. The Windows Media Player (client) is built in to most Windows applications

Streaming Media – Continuous?

Internet connections using TCP/IP send data in packets that are not always sent in a continuous stream.

For streaming to work, the client receiving the data must collect and save a small amount of data in a buffer. Once the client player takes the data from the buffer and presents it, it is no longer stored.

If the data does not come quickly enough, the presentation of the data will not be smooth.

Live streams vs. On-demand

A stream can be delivered live (webcast) or on-demand. Live webcasts can only be joined in

progress, and played forward (controlled at the server)

On-demand streaming can be manipulated forward or reversed, also started and stopped (controlled at the client)

BroadcastsMany Internet sites are now charging

for content:Yahoo!Broadcast allows you to subscribe to its collection of audio and video on the Internet (http://broadcast.yahoo.com)CNN.com offers a streamed version of its collection of news for a subscription price. Google Directories contains broadcast information (http://directories.google.com), but beware some lists may be outdated

National Public Radio

National Public Radio (NPR) is streamed on the Web at http://www.npr.org/

The NPR Web site provides not only the 24-hour news stream, but also lets you search via keywords through the NPR archives of online programming.

Synchronized Multimedia

As a standard for Web page authors to integrate multimedia presentations, the World Wide Web Consortium (W3C) created SMIL. (Synchronized Multimedia Integration Language). SMIL choreographs the interaction of audio, video,

text, and graphics in multimedia presentations so they can be combined in real-time.

It allows web page authors to describe how the objects should appear and interact on the Web page.