Changes to Windows Media Services

Windows Media Services was redesigned for this release, making the server more flexible, unifying the core components, and simplifying the administrative process. Following is a brief overview of changes in the current release:

• MMS rollover. If clients that support the Real Time Streaming Protocol (RTSP) connect to a server running Windows Media Services 9 Series using a URL that starts with a Microsoft Media Server (MMS) moniker (for example, mms://server_name/content_clip1.wmv), the server uses protocol rollover to stream the content to the client using RTSP to provide an optimal streaming experience. Clients that support RTSP include Windows Media Player 9 Series or later or other players that use the Windows Media Player 9 Series ActiveX control.

  Earlier versions of Windows Media Player and other players that do not support the RTSP protocol can still connect to the server by using a URL with an mms:// prefix. However, automatic protocol rollover from MMS to MMS with UDP-based or TCP-based transports (MMSU or MMST), or even HTTP, may occur as the server tries to negotiate the best protocol for the Player and provide an optimal streaming experience.

  To make sure that your content is always available to clients that connect to your server using a URL with an mms:// prefix, ports on your firewall must be opened for all of the connection protocols that might be used during protocol rollover. For more information, see Using firewalls.

• Four services combined into one—the Windows Media Services service. The Windows Media Services service replaces the four separate services that comprised Windows Media Services versions 4.0 and 4.1: Windows Media Monitor Service, Windows Media Program Service, Windows Media Station Service, and Windows Media Unicast Service.
• Expanded use of plug-ins. In previous versions of Windows Media Services, you could expand the server through the use of custom authentication, authorization, or event notification plug-ins; other plug-in types were not supported. This version considerably increases the number of ways that you can customize and configure the server through an expanded plug-in architecture. Interfaces are provided for most of the plug-ins so you can build custom plug-ins that enhance the server's capabilities. You can use plug-ins to control the following behaviors:
  • How the server reads from devices. Use data source plug-ins to enable the server to read from databases, device drivers, and different network locations.
  • How data is sent over the network. Use data writer plug-ins with control protocol plug-ins to support a variety of network protocols.
  • How server-side playlists are translated. Use playlist parser plug-ins to enable the server to support different metafile formats.
• Expanded use of publishing points. Publishing points handle the association of content to streams. Publishing points expand the basic functionality provided in previous versions of Windows Media Services and greatly simplify the functionality that was formerly provided by using a combination of programs, streams, and stations. You can now create both broadcast and on-demand publishing points, and you can customize these publishing points through property pages that control different server functions.
• Flexible server-side playlists. Every publishing point (including on-demand publishing points) can stream content from a playlist. Each item in the playlist has a set of independent attributes such as repeat, duration, genre, and so on. You can specify these attributes to meet your particular needs. Playlists can even be modified during a broadcast, allowing you to respond to situations without having to interrupt your stream.
  • Absolute Playlist Time. Adds the playlist timing value wallclock, which can be used to automate broadcast schedules by assigning real-world clock values in Coordinated Universal Time (UTC) to attributes in server-side playlists.
• Flexible event architecture. In previous versions of Windows Media Services, external events were available only through station and unicast Microsoft ActiveX® objects. In this version, events are available internally through server interfaces, as well as externally through both Windows Management Instrumentation (WMI) and Simple Network Management Protocol (SNMP) events.
• Fast Streaming. In previous versions of Windows Media Services, content was streamed at a constant bit rate to the clients. Fast Streaming allows for a combination of streaming, downloading, and caching in order to provide the best user experience. The following features provide Windows Media Services Fast Streaming capabilities:
  • Fast Start. Enables the beginning portion of the content to be quickly downloaded to Windows Media Player at the maximum available bandwidth, reducing the amount of time required to fill the buffer requirement of the Player and reducing the amount of time a user has to wait to begin receiving the stream.
  • Advanced Fast Start. Adds to Fast Start capabilities by allowing the Player to begin playing content as soon as its buffer receives a minimum amount of data, further reducing the amount of time a user has to wait to begin receiving the stream.
  • Fast Cache. Enables Windows Media Services to make use of any additional bandwidth to send out additional data to the buffer of the Player, allowing the Player to better withstand network bandwidth fluctuations.
  • Fast Recovery. Enables the server to provide an uninterrupted viewing experience to users receiving content over high latency network connections, such as wireless and satellite networks, by using forward error correction to greatly reduce packet corruption and interruption.
  • Fast Reconnect. Enables the server to automatically restore client connections—including encoders, distribution servers, and players—that are lost during a broadcast due to network conditions.
• Play While Archiving. In previous versions of Windows Media Services, broadcast content could be archived to a file, but the archived content could not be made available for on-demand requests or rebroadcast until archiving was stopped. In this version, archived files can be made available for on-demand requests or rebroadcast even before the broadcast that is being archived has finished.
• Advanced FF/RW. This version of Windows Media Services contains improved fast-forward and rewind ("trick mode") functionality for the video portion of encoded files. This feature stabilizes network bandwidth availability by smoothing the rate at which data is sent. Potential server performance bottlenecks are reduced because the server must read less presentation data from the source content disk, while delivering a seamless experience to clients.
• Improved packet resend logic. In previous versions of Windows Media Services, packet resend requests from clients could only be fulfilled for the last two seconds of content. In this version, 10 seconds of data is stored in the server buffer, allowing for better error correction and stream quality.
• Server-based content repacketization. In previous versions of Windows Media Services, the server could only stream data packets as defined by the stream format. In this version, the server administrators can set the optimum packet size for streaming in their environment, and the server can reallocate data to stream packets based on that property setting. This optimization is only applicable when streaming content using User Datagram Protocol (UDP) packets and the Real Time Streaming Protocol (RTSP).
• IPv6 support. This version of Windows Media Services has support for Internet Protocol Version 6 (IPv6) addressing.
• IGMPv3 support. Internet Group Management Protocol (IGMP) version 3 provides Windows Media Services the ability to help prevent problems with multiple broadcast servers that use the same multicast IP address. This feature requires that the clients connecting to the multicast are using Windows Media Player 9 Series or later.
• Broadcast Auto-Start. In previous versions of Windows Media Services, broadcast publishing points had to be started manually in the event of an interruption, such as a power failure. In this version, you can configure your broadcast publishing points to begin running again automatically whenever the Windows Media server starts.
• Additional Windows Server System platform support (x64). Windows Media Services is available as a component in x64-based versions of the Microsoft Windows Server 2003 operating system. (Note that x64-based computers are computers running 64-bit processors with an extended x86 instruction set, such as the Advanced Micro Devices (AMD) AMD64 and Intel Extended Memory 64 Technology (EM64T) processor lines.) Windows Media Services is not available in Itanium-based versions of the Windows Server 2003 operating system. For more information, see the Microsoft Web site.

The following table cross-references Windows Media Services version 4.x terms and features to current Windows Media Services terms and features.

Note

• The features in Windows Media Services features differ depending on which version of Windows Server 2003 you are running. For a complete list of the features available in each version of Windows Media Services, see Comparing versions of Windows Media Services.

Related topics

• Understanding protocols
• How protocol rollover works
• Using firewalls
• Configuring firewalls for unicast streaming
• Advertising support
• Deploying Windows Media Services
• Managing your Windows Media server
• Platform components
• Plug-in architecture
• Server-side playlists
• Understanding playlists
• Understanding publishing points
• Upgrading Windows Media Services
• Wireless delivery
• Working with the administrative interfaces
• Getting started