DirectShow Extensions (Windows CE 5.0)
The Windows CE 5.0 Networked Media Device Feature Pack extends the functionality included in DirectShow to include the following:
- Fast Start.
- HTTP 1.1 Streaming Support for non WM media.
Fast Start
The NMD_UI sample application takes advantage of new features in Windows CE 5.0 such as Fast Start, that reduce initial startup latency when playing streaming content.
Fast Start reduces initial startup time when playing streaming content. During the buffering phase of playback, the server will stream content to the client as fast as the network link will allow, instead of streaming at the bit rate of the content. This means that the buffering phase can be much shorter depending on buffering settings, link bandwidth, and content bit rate. More information on Fast Start can be found at the following link:
Windows Media Optimization for Windows CE
HTTP 1.1 Streaming Support
The Windows CE 5.0 Networked Media Device Feature Pack extends HTTP streaming support to non-ASF formats such as AVI and MPEG. This is now provided by a new DirectShow filter called the Generic Streamer Filter. This filter does not replace the existing DirectShow Filter used to stream WM encoded content.
Before this filter, non ASF files were downloaded locally and played from the cache. This caused two main issues: A file larger than available storage could not be played, and the user could not seek to a location in the file.
The filter behaves in the following ways:
- This filter connects to any HTTP server compliant with the W3C HTTP specification.
- When connecting to a server supporting the HTTP 1.0 protocol, the client will be able to simply play a file from the beginning to the end
- When connecting to a server supporting the HTTP 1.1 protocol, the client will be able to play the file starting any position, pause and resume playback, seek to any position in the file, and reconnect from the current position if the server connection is lost.
The filter provides support for the following customer scenarios:
- If the user opens an HTTP stream through Windows Media Connect, the stream plays on the device.
- If the user opens an HTTP stream on the Internet, the stream plays on the device.
- If the user pauses and resumes the playback on the device, playback continues at the point where it was paused.
- If the user seeks to any random position on the device, playback continues from that location.
- If the connection is lost with the server (due to timeout or bad network); the device will re-buffer and restart the playback from the current position. This will only take place if the network is restored within 15 seconds. Otherwise, playback will stop and will not restart.
See Also
Windows Media DRM for Network Devices
Windows Media digital rights management (DRM) is designed to protect and securely deliver content for playback on a portable or network device.
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