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Windows Media Format is optimized for streaming and playing back audio, video, and script data. This format is primarily used in streaming presentations over the Internet and local intranets, but it has a number of other uses, such as in downloading and playing back music on a portable device.
The following sections discuss some of the concepts behind using Windows Media Format in developing client and server applications:
A Windows Media file is an audio, video, or script file that can be compressed with one of a few supported codecs (compression-decompression schemes). This SDK enables read and write operations to be performed with these file types.
The Windows Media Format SDK can work with various digital rights management (DRM) systems to encrypt content in such a way that only a licensed user can play it back. DRM is integral to the future development of Windows Media files.
To use the name Windows Media Format, a software or hardware vendor must enter into a license agreement with Microsoft.
For streaming media, there are clearly two different types of application: those at the server end of a system, for compressing, encrypting and writing Windows Media files; and those at the client end, for reading, decompressing, and decoding Windows Media files.
A typical client-side application for the Windows Media Format SDK would be in writing a player designed to receive and play back audio and/or video content streamed out over the Internet. Another use would be in receiving an audio stream from the Internet on a personal computer, and then downloading and playing the file on a portable playback device. For this, you would have to implement the Windows Media Device Manager feature of the Windows Media Format SDK. The Windows Media Device Manager functionality supports any DRM system in use, as long as that system conforms to the specifications laid out by the Secure Digital Music Initiative (SDMI) committee.
A typical server-side application for the Windows Media Format SDK would be in developing an encoding tool, taking audio or video input in its various raw forms, and creating Windows Media files in preparation for streaming them over the internet.
Another application would be going a step further and building a full-featured server to handle both encoding and streaming data.
An important point to remember is that a Windows Media file is not readily suitable for editing purposes: the file is in a packetized format optimized for streaming, not editing. For this reason, editing tools need the Windows Media Format SDK to both read and write Windows Media files, in particular to read them in and convert them into a format that can be edited more easily.
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