Figure 5. Windows Media Player displaying media-sharing features
Figure 6: The Share with Media Devices application in Control Panel displaying available media player and rendering devices
After they choose to share with media devices, other Windows PCs, media player devices, and media controllers (described in further detail later in this paper) can automatically discover the DMS and play content from the media library.
Figure 7 shows the protocol layers in a digital media server. DMS devices support Wi-Fi or Ethernet for connectivity. DMS devices implement Transmission Control Protocol/Internet Protocol (TCP/IP),User Datagram Protocol (UDP)/IP, and HTTP. DMS devices implement HTTP and extensions to transfer content to other devices in the network. Some DMS devices use RTP for transfer. DMS devices implement the UPnP MediaServer functionality that includes two services:
Content directory service (CDS)
Connection manager service (CMS)
Figure 7: Protocol stack for a digital media server
To expose media through the CDS from the Windows 7 NSS, the files must be added to the Windows Media Player library. Windows 7 and Windows Media Player provide a simple interface to identify which folders contain files to be shared as a library. Music, pictures, videos, and recorded TV that are added to the Windows 7 library are automatically added to the Windows Media Player library and shared, if media sharing is enabled. Only content that is supported for playback by Windows Media Player is shared. Figure 8 shows Windows 7 libraries. Media files or folders that are added to a library are added to Windows Media Player and can be shared by the NSS.
Figure 8. Windows 7 library view from Windows Explorer
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