Windows Media Technologies
Windows Media Technologies 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".
The current release of Windows Media is 7 for Windows, and an updated Macintosh
beta is also available. The latest free downloads, as well as more information,
are available at Microsoft's Windows Media site.
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SCALABILITY |
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When used with a Windows Media Server for true
streaming, Windows Media offers scalability through "Intelligent
Streaming": each file can contain up to five video tracks. At the
beginning of playback, the Media Player and the Windows Media Server
communicate to pick the video track which best matches the viewer's connection.
Windows Media only supports one audio track, so it cannot play different audio
tracks for different connections. This means that viewers with a T1 connection
will hear the same audio as viewers with a 56K modem.
In addition to initially choosing between the video tracks, the Media Player
can also drop frames and/or degrade image quality to maintain real-time
playback over slower connections. In extreme cases, the Media Player may only
play the audio track to compensate for extremely slow connections.
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WINDOWS MEDIA VIDEO CODECS |
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Codec |
Pros |
Cons |
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Excellent
image quality at wide range of bitrates |
Playback
not yet fully supported on Mac (beta with full support released October 2000) |
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Standards-based
codec |
Typically
lower image quality at a given bitrate than Windows Media Video |
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Windows
Media Screen Codec |
Specially
optimized for use on screen captures and some animations |
Not
appropriate for live video |
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Compatible
with Mac |
Not
standards-compliant; no longer recommended |
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WINDOWS MEDIA AUDIO CODECS |
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Codec |
Pros |
Cons |
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Windows
Media Audio |
Very good
quality at a range of bitrates |
Not well
suited for low-bitrate voice |
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Sipro
ACELP.net |
Decent
voice quality at low bitrates |
Not
appropriate for music; requires fairly "clean" speech to work well |