Streaming Media

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Streaming video on the Internet generally comes in two varieties, those that are downloadable and available 'on demand' and those that follow a more traditional live televsion broadcasting or 'streaming' approach to distribution. In truth, the most recent advances in Internet video technologies generally adhere to a mixture of both approaches listed above, but it is still helpful, at this time, to understand the differences and applications of each type. First, 'Video On Demand' technologies offer the ability to view archived material at any time, similar to any other type of data that is acquired on the Internet. Generally these offer the best image quality as the files do not have to be created in real time. High quality video files relative to today's available Internet bandwith, download times may be much longer than actual program times of the individual files being downloaded. By contrast, 'real-time' streaming (also referred to as Webcasting or Netcasting) creates a video stream of a live video event or archived material in real time. These files download to the desktop while they play. Although webcast events can be archived for later viewing, the real-time stream is, as the name implies, a real time event that must be viewed while it is being broadcast. Also, to account for bandwidth limitations, real-time streaming files must be much smaller than those of their downloadable counterparts. Therfore, the image and sound quality of today's real-time streaming technologies is generally much lower than that of archived on-demand downloadable movies.

There are a number of different video streaming technologies currently available, each offers their own strengths and weaknesses. We have identified and tested three of the primary video streaming tools:

Apple's Quicktime
QuickTime is Apple's multi-platform, industry-standard, multimedia software architecture. It is used by software developers, hardware manufacturers, and content creators to author and publish a wide range of media. Some of the highlights of QuickTime include:

• Well-suited to delivery of media everywhere: WWW, CD-ROM, DVD, broadband, kiosk, presentations
• Macintosh and Windows are equally well supported
• Includes powerful interactive capabilities (everything a DVD-Video can do, and much more).
• "Movie alternates" allow multiple versions of a movie to be created and automatically selected, to give each user the optimum experience.
• Used not only for delivery, but also editing and production
• Supports every major file format for images, including JPEG, BMP, PICT, PNG, GIF.
• Features built-in support for digital video, including MiniDV, DVCPro and DVCam camcorder formats, as well as support for AVI, AVR, MPEG-1 and OpenDML.
• Supports key standards for web streaming, including HTTP, RTP and RTSP
• Capable of playing MP3 content, QuickTime also supports Timecode tracks as well as MIDI standards such as the Roland Sound Canvas and GS format extensions. (Terran, Inc)

Real Network's G2
RealVideo (aka "RealMedia") is a network oriented, streaming media architecture developed by RealNetworks. RealSystem G2 is the second generation of RealVideo, and represents a major improvement in quality, supported media types, and features.

RealSystem G2 is a streaming architecture, offering both server-based "true streaming" and serverless "http streaming" (aka "progressive download"). There are performance and scalability advantages with the server, but you can get started without one. However, high volume sites definitely need a server for improved delivery performance. RealNetworks is the only company which offers servers for RealSystem G2.

RealSystem G2 is most appropriate for network delivery of audio, video, and other media types such as text and Flash animations. It is less often suitable for CD-ROM or DVD delivery due to the high CPU requirements at higher bandwidths. Real files cannot be edited or re-compressed once they are encoded into the Real format. (Terran, Inc)

Microsoft's Media Player
Windows Media Technologies (aka simply "Windows Media" and formerly known as "NetShow") is Microsoft's streaming media architecture. Focused on network delivery of video and audio, Windows Media offers server-based "true streaming" as well as limited support for serverless "http streaming" (aka "progressive download").

*Technically, the term "NetShow" refers to the server software. The files used are Active Streaming Format (ASF), and playback is via the Windows Media Player.

NetShow servers support "true streaming" (in their case, called "intelligent streaming"): the ability to guarantee continuous delivery of media even if the networks' performance degenerates. If this happens, NetShow will automatically send less video data (thus reducing the quality). If the amount of available bandwidth decreases more, NetShow will degrade video quality further, until only the audio is left. ASF files can also contain two versions of the video track, to further optimize for both high- and low-bandwidth connections. (Terran, Inc)

All of the technologies listed above can be used for either real-time streaming events or for archived on-demand downloadable content. And in some cases, dynamic versions of both real-time streamed content and/or archived downloadable content can be used simultaneously, where the streaming server application delivers the most appropriate version of particular content to clients based on the available Internet bandwith between the server and the the client requesting the file.