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To stream digital media content over a network, you must use a Windows Media server. This article introduces Microsoft Windows Media Services 9 Series, an industrial-strength platform for streaming live or on-demand content over the Internet or an intranet. This article is intended for intranet and Internet broadcasters, IT professionals, or Web architects who have networking knowledge and previous experience with Windows Media Services.
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David Nelson
Microsoft Corporation
April 2007
Applies to: Microsoft® Windows Media® Services 9 Series
Contents
IntroductionWindows Media 9 Series is the term for the family of digital media software developed by Microsoft. All of the software is designed to work together to provide the optimal digital media experience.
Windows Media Services is a platform for streaming audio and video content to clients over the Internet or an intranet. These clients may be other computers or devices that play back the content using a player, such as Windows Media Player, or they may be other computers running Windows Media Services (called Windows Media servers) that proxy, cache, or redistribute your content. Clients can also be custom applications that have been developed using Windows Media SDK Components.
The content that your Windows Media server streams to clients can be either a live stream or a prerecorded digital media file. If you are planning to stream live content, your server will connect to encoding software, such as Windows Media Encoder, that is capable of broadcasting a live stream in a format supported by the server. You can also stream files that have been encoded by Windows Media Encoder, Microsoft Producer for Microsoft Office PowerPoint 2003, Windows Movie Maker, and many third-party encoding programs.
You can use Windows Media Services to configure and manage one or more Windows Media servers that deliver your content to clients. Simplified deployment and administration ensures that you can easily set up and administer Windows Media servers, even if you are not familiar with streaming concepts.
For more information the Windows Media platform and its complete set of end-to-end components that deliver the ultimate solutions for digital media users, see What is the Windows Media Platform?
This article introduces some of the features of Windows Media Services and introduces concepts that are important to understand as you prepare to implement a streaming media system.
NoteThe features in Windows Media Services differ, depending on which version or edition of the Microsoft Windows Server operating system that you are running. For a complete list of the features in Windows Media Services that are available in each version of Windows, see Decide which version of Windows Server is right for you.
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Downloading vs. streaming contentYou can deliver digital media files to clients over a network by using one of two methods: downloading or streaming. This topic provides an overview and a comparison of each method.
Downloading
To deliver content to users by using the downloading method, you typically save the content to a Web server and provide users with a link to the content by adding the link to the content on a Web page, for example. The user then clicks the link, downloads the file to his or her local hard disk, and then plays back the content using a player.
Downloading requires that users copy entire files to their computers before they can play the content, which consumes both time and disk space. In addition, because the entire file must be downloaded to a computer before it can play, downloading can not be used with live content.
Downloading does not make efficient use of available bandwidth. When a client begins to download a digital media file, all available network bandwidth is used to transfer the data as quickly as possible. As a result, other network functions may slow down or be disrupted.
Streaming
To deliver content to users by using a streaming method, you can save the content to a Windows Media server, and then assign the content to a publishing point. You can then provide users with access to the content by either creating an announcement file or by supplying users with the URL of the publishing point. You can embed the announcement file or the URL in a Web page or send it in an e-mail message. When the user clicks the link or the announcement file, the player opens and connects to the stream.
Streaming uses bandwidth more efficiently than downloading because it sends data over the network only at the speed that is necessary for the client to render it properly. This helps prevent the network from becoming overloaded and helps maintain system reliability. There is typically a delay between the time the stream is received by the player and the point at which it begins playing because the player must first buffer the data in case there are delays or gaps in the stream. Because data streaming and rendering occurs at the same time, streaming also enables you to deliver live content.
To stream content smoothly, the bit rate of the content must be lower than the bandwidth of the network. If the bit rate is higher than the available bandwidth, the player will attempt to thin the stream so it can render the stream properly by using a process called stream thinning. Because of this, the player may render only key frames of the video stream with audio so that the video is not in motion, creating a viewing experience similar to a slide show. If the bit rate requirements greatly exceed the available bandwidth, video playback may stop altogether and only the audio portion will be played.
The impact of inadequate available client bandwidth can be minimized if multiple-bit-rate (MBR) content is streamed. MBR content enables the player to request a lower bit rate stream from the server so that stream thinning is not necessary.
Fast Streaming
Fast Streaming provides several features that combine the advantages of streaming and downloading.
The server can use the Fast Start and Advanced Fast Start features to ensure that the client can begin playing the content as quickly as possible after the stream begins. The Fast Start feature enables the player to download and buffer a small portion of the content from the server as fast as the network will permit before the content begins to play. After the buffer has been filled on the player, the server slows down the stream until it matches the rendering speed of the player.
The server can take Fast Streaming one step further by using the Advanced Fast Start feature to enable clients to begin playing the content even before the player's buffer is full. When the player receives a minimum amount of data, it can begin playing the content. The player's buffer continues to fill at an accelerated rate—a rate that is faster than the encoded bit rate of the content. When the buffer is full, Fast Start acceleration stops and the player begins receiving data at the encoded bit rate.
When the server uses the Fast Cache feature, it streams all of the content to the player at the highest possible bit rate so that the effects of network congestion or interruption can be minimized. As with normal streaming, the player begins rendering the content when the necessary amount of data has been buffered. The rest of the data is stored in a temporary cache on the client computer.
If you are streaming variable-bit-rate (VBR) content, the amount of bandwidth required to transmit the stream can fluctuate based on the complexity of the content. Fast Streaming can take advantage of periods of lower bandwidth by sending extra data to the player to replenish the content buffer, enabling the VBR content to play back smoothly when streamed from the server.
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Streaming from a Windows Media server vs. a Web serverYou can deliver Windows Media-based content either from a server running Windows Media Services or from a Web server. However, a Windows Media server is designed specifically for streaming Windows Media-based content; a standard Web server is not. If you decide to use a Web server, be aware of the following differences in the way the content is delivered, which can affect the playback quality:The method of sending data differs between a Web server and a Windows Media server. A Web server is designed to send as much data as it can, as quickly as possible. This is the preferred method for sending static images, text, and Web page scripts, but it is not the best method for streaming digital media. Ideally, the data packets for streaming media content should be delivered in real time, not in large bursts, and players should receive packets immediately before rendering them. A Windows Media server regulates the delivery of packets according to feedback information it receives while sending a stream to a player and according to the configuration of certain features, such as Fast Cache and Fast Start. When a player receives packets in this way, the presentation is much more likely to be smooth. Because bandwidth use is controlled, more users can connect at the same time and still receive streams that are free of interruptions. Web servers do not support multiple-bit-rate (MBR) video. When a file streams from a Web server, the quality of the delivery is not monitored and the bit rate cannot be adjusted, which can cause the playback quality to vary during the duration of the stream and can result in a poor user experience. Web servers cannot use the preferred delivery protocol for streaming media, User Datagram Protocol (UDP), so delivery of a stream is more likely to be interrupted by periods of silence while the player buffers data. Web servers do not support live streaming or multicast streams. Web servers do not support indexed Windows Media files. (Indexing provides users with a means of fast-forwarding and rewinding through a file that is streaming.) A Windows Media server includes built-in monitoring and logging capabilities with which you can gather valuable information about your streaming media session and its audience.
NoteThere are times when you may prefer to stream from a Web server—for example, if you plan to offer only a small amount of content or if you have a site with limited resources. A Web server can also be used for downloading files that you do not intend to stream, such as files with a high bit rate that are intended for local playback only. For more information, see Streaming from a Web Server.
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Streaming media system overviewA streaming media system based on Windows Media Technologies typically consists of a computer running an encoder (such as Microsoft Windows Media Encoder), a server running Windows Media Services, and players. The encoder enables you to convert both live and prerecorded audio, video, and computer screen images to Windows Media Format. The server running Windows Media Services, called a Windows Media server, enables you to distribute the content over a network. Users receive the content you distribute by using a player, such as Windows Media Player.
In a typical scenario, a user clicks a link on a Web page to request content. The Web server redirects the request to the Windows Media server and opens the player on the user's computer. At this point, the Web server no longer plays a role in the streaming media process and the Windows Media server establishes a direct connection with the player and begins streaming the content directly to the user.
The Windows Media server can receive content from several different sources. Prerecorded content can be stored locally on the server or retrieved from a networked file server. Live events can be captured using a digital recording device and processed through an encoder before being sent to the Windows Media server for broadcast. Windows Media Services can also rebroadcast content streamed from a publishing point on a remote Windows Media server.
NoteFor information about implementing security measures in your streaming media system, see "Configuring security options" in Windows Media Services Help.
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Ensuring the stability of your streaming media systemTo ensure that your streaming media system is stable, redundant, and capable of bearing the predicted load, keep the following in mind:If you plan to encode live content, it is recommended that you install the encoder and Windows Media Services on separate computers. Live encoding requires a large amount of processing capability; the additional load of serving client requests can adversely affect the quality of an encoded stream. Have multiple encoders encoding content so that publishing points on your Windows Media servers can switch to an alternate source in case there is a problem on the original encoder source. If you want to archive encoded content for later playback, do not use the encoder to create the archive file. Instead, configure your Windows Media server to create an archived copy. This reduces the processing load on the encoding computer. Distribute content between numerous Windows Media servers. This enables the servers to provide content to different network segments, which reduces the number of routers that the stream must traverse to reach clients and improves the overall stream quality. In addition, extra servers provide redundancy and additional capacity if there are any server problems. If you intend to stream high volumes of Windows Media files, consider dedicating a separate NTFS volume for storing the files. An NTFS volume permits the use of access control list (ACL) that checks on your content files, as well as better file management capabilities. If you intend to stream high volumes of on-demand video content that is indexed to support fast-forward, skip, rewind, and pause capability, consider using the Advanced FF/RW feature to improve 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, and reduces potential server performance bottlenecks by reading less presentation data from the source content disk, all while delivering a seamless experience to clients. Copies of the original source content files must be created that support the different fast-forward or rewind speeds requested by clients. Consider using multicast streaming with unicast rollover. Multicast streaming can deliver content to any number of clients from a single stream. When additional clients connect through a multicast-enabled network, they do not require extra bandwidth from the server or place an additional load on the network, thus increasing the efficiency of the stream.
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Obtaining contentYou can stream many types of content in Windows Media Format, including a radio show, a song, a television program, or a music video. Content can either be a stored Windows Media file or a live stream. You can also create a playlist file that references a combination of files and live streams and generates a continuous stream. The following table lists software available from Microsoft that you can use to create and edit Windows Media-based content.
| Tool | Description |
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Windows Media Encoder
| Use to convert live and prerecorded content to Windows Media Format. Windows Media Services is compatible with Windows Media Encoder version 4.1 and later.
| Windows Media Encoding Script
| Use this command-line tool to convert live and prerecorded audio and video into mk:@MSITStore:\\DprodUE\DProdue\Posted_Builds\Encoding_Utility\Daily\WMEncUtil.chm::/htm/windowsmedia8encodingutility.htm or mk:@MSITStore:\\DprodUE\DProdue\Posted_Builds\Encoding_Utility\Daily\WMEncUtil.chm::/htm/windowsmedia8encodingutility.htm.
| Windows Media Player
| Use to rip existing content from a CD.
| Windows Movie Maker
| Use to capture audio and video and do simple video editing.
| Windows Media Stream Editor
| Use to split or combine streams in existing Windows Media files into new Windows Media files.
| Microsoft Producer for Microsoft Office PowerPoint 2003
| Use to combine slides from a presentation created in Microsoft Office PowerPoint or Web pages created with Microsoft FrontPage with audio and video.
| Windows Media File Editor
| Use to open and edit a file with a .wmv, .wma, or .asf file name extension. This utility enables you to trim the start and end points of a file, as well as add attributes, markers, and script commands.
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For more information about obtaining and using any of the above products as well as information about additional content creation tools, see the Windows Media Professional Solutions.
NotesSupport for encoding content in Windows Media Format is included in many third-party programs, such as Vegas Video and Sound Forge from Sonic Foundry, Premiere from Adobe, and VideoWave from MGI. Most of these products are used for advanced editing and processing of video and audio. When you finish working on a file, the program enables you to encode it as a Windows Media file. Windows Media Services can create content from a broadcast stream using the WMS Archive Data Writer plug-in. For more information, see "Archiving content" in Windows Media Services Help. Windows Media Services cannot stream variable-bit-rate (VBR) MP3 files. Content streamed by Windows Media Services must meet the minimum supported content length of the player to ensure reliable playback. The minimum supported content length for Windows Media Player 9 Series or later is 5 seconds. The minimum supported content length for previous versions of Windows Media Player is 30 seconds.
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Setting up Windows Media ServicesAfter you have obtained your content, the next step is to set up a server running Windows Media Services to distribute that content. The basic steps involved in setting up a Windows Media server include adding and configuring publishing points to identify the content you plan to stream, and communicating to users that the content is available.
A Windows Media server uses publishing points to translate a client request for content into a physical path on the server hosting the content. You can add two types of publishing points to a Windows Media server, broadcast and on-demand. If you want to stream live content from an encoder, a broadcast publishing point is the best choice. If you plan to stream a file and want to allow users to control playback of the content (for example, to pause, rewind, or fast-forward it), an on-demand publishing point is the best choice.
After you have added a publishing point and identified the content you want to stream from it, you need to communicate that the content is available. An easy method for accomplishing this is to create an announcement for the content.
You may also want to implement some of the more advanced features available through Windows Media Services. For example, you can modify settings to limit the number of client connections, set up security measures to protect your content, log data about client activity, and set up a distribution server.
When selecting the type of publishing point to use, you should consider how you want to deliver the content; for example, whether you want to deliver the content as a unicast or multicast stream. With a unicast stream, clients connect to a Windows Media server to access content. With a multicast stream, the server streams content to a single multicast IP address on the network, and all clients access that IP address to receive the stream instead of connecting to the server. This reduces the amount of bandwidth required on the network as the single stream is able to fulfill multiple client requests.
You can deliver content as a unicast stream from either an on-demand or a broadcast publishing point. You can deliver content as a multicast stream only from a broadcast publishing point.
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Delivering content as a unicast streamA unicast stream is a one-to-one connection between the server and a client, which means that each client receives a distinct stream and only those clients that request the stream receive it. You can deliver content as a unicast stream from either an on-demand or a broadcast publishing point.
Unicast streaming is the default method by which a Windows Media server delivers content. Unicast streaming is automatically enabled by the WMS Unicast Data Writer plug-in, which is enabled by default.
The following figure shows an example of delivering content as a unicast stream by using an on-demand publishing point.
As shown in the figure, there is an on-demand publishing point named TV1 on the Windows Media server called Server1. This publishing point identifies the location of the content you want to stream. The content can be hosted on the local server or a network file system. You can source from a specific file, a playlist file, or a directory. In this example, the publishing point is sourcing from a playlist file that is stored locally on Server1. When you are ready for users to begin streaming, you can create an announcement to give users the URL to the content. Because the content is being delivered as a unicast stream, each player has a unique connection to Server1.
Delivering content as a multicast streamMulticast streaming is a one-to-many relationship between a Windows Media server and the clients receiving the stream. With a multicast stream, the server streams to a multicast IP address on the network, and clients receive the stream by subscribing to the IP address. All clients receive the same stream. Because there is only one stream from the server regardless of the number of clients receiving the stream, a multicast stream requires the same amount of bandwidth as a single unicast stream containing the same content. Using a multicast stream preserves network bandwidth and can be useful for low bandwidth local area networks.
You can deliver content as a multicast stream only from a broadcast publishing point. In addition, your network routers must be multicast-enabled, meaning that they can transmit class-D IP addresses. If your network routers are not multicast-enabled, you can still deliver content as a multicast stream over the local segment of your local area network.
The following figure shows an example of content being distributed from an encoder as a multicast stream by using a broadcast publishing point.
These steps describe one way you can multicast live content from an encoder, as shown in the previous figure.Send the live images from a digital video camera to a video capture card on a computer running Windows Media Encoder. The images are encoded into Windows Media Format, and then streamed to the server using Hypertext Transfer Protocol (HTTP). On the Windows Media server called Server1, use the Add Publishing Point Wizard to add a broadcast publishing point that sources from the encoder. As part of the wizard, you may choose to allow unicast rollover. Unicast rollover ensures that players that cannot access the multicast stream can still receive the content by switching to an available unicast stream. For example, a player may be unable to access the multicast stream if the network routers are not multicast-enabled, or if the player is beyond the time-to-live (TTL) radius of the multicast stream. Use the Multicast Announcement Wizard to create an announcement to provide users with the URL to the content. The wizard can create a multicast information file (with an .nsc file name extension), an announcement file (with an .asx file name extension), the code necessary to embed an announcement within a Web page, or any combination of those three options.
NoteAnnouncing your content to usersAfter you set up your Windows Media server and the content you want to stream, you need to let users know the content is available and how to access it. Users can access content by typing the URL to the content in their players. However, users do not always know the URL or even that your content exists. To make it easy for users to access your content, you can create an announcement. An announcement is a Windows Media metafile with an .asx extension that gives a player the information needed to connect to a Windows Media server.
Announcing a unicast stream
To enable players to access a unicast stream, you can create an announcement file by using the Unicast Announcement Wizard. An announcement provides the information that the player needs to connect to and receive your content. You can place a link to an announcement on a Web page, make the announcement available on a shared network location, or send an announcement in an e-mail message. Users can access your content either by clicking the link on the Web page or by directly opening the announcement.
Announcing a multicast stream
To enable players to access a multicast stream, you can create an announcement file and a multicast information file by using the Multicast Announcement Wizard. An announcement provides the information that the player needs to connect to and receive your content.
A multicast information file is a Windows Media metafile with an .nsc extension that contains information a player needs to decode the stream. You can place a link to the announcement on a Web page, make the announcement available on a shared file location, or send an announcement in an e-mail message. Users can access the announcement either by clicking the link to the announcement on the Web page or by directly opening the announcement. The announcement opens briefly, points to the multicast information file, and then the player begins receiving the content.
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Administering Windows Media ServicesAdministering Windows Media Services has never been easier. With the three different administration tools available in Windows Media Services, you can administer your Windows Media server in a variety of ways depending on your needs and your environment:Windows Media Services snap-in for Microsoft Management Console (MMC). This full-featured interface has been designed to simplify your server administration tasks. You can add the snap-in to MMC on any computer running the Standard, Enterprise, or Datacenter Editions of the Windows Server 2003 or Windows Server "Longhorn" operating systems, or you can access the snap-in by using a Remote Desktop connection. In addition, you can launch wizards from the snap-in to help ease setup and configuration of common management activities. Windows Media Services Administrator for the Web. This interface makes remote administration of your server easy through the use of a Web browser. Using a Web interface allows you to administer Windows Media Services over a firewall, on a low-bandwidth network connection, or in a non-Windows environment. This Web-based administrator uses Active Server Pages (ASP) hosted by Microsoft Internet Information Services (IIS) and enables you to perform many of the same functions that you can with the Windows Media Services snap-in. In addition, Windows Media Services Administrator for the Web has been designed to closely resemble the snap-in user interface for ease of use. Your computer must be configured using the NTFS file system before you can install and use Windows Media Services Administrator for the Web. Command-line scripts. This interface enables you to manage your server quickly by using a Telnet connection or batch programs.
After you have selected an administration method, you can manage the settings of your Windows Media server. These settings control the delivery of content to your client and may apply to properties, plug-ins, publishing points, and server-side playlists.Properties are used to set rules that apply to the core behavior of Windows Media Services. You can apply properties to either the entire server or to specific publishing points. Plug-ins are used to supply additional features, such as logging, authentication, data sources, and control protocols. You can apply plug-ins to an entire Windows Media server or to specific publishing points. For more information, see "Configuring properties and plug-ins" in Windows Media Services Help. Publishing points are used to manage and distribute your content. There are two types of publishing points: on-demand publishing points and broadcast publishing points. For more information, see "Using publishing points" in Windows Media Services Help. Server-side playlists are collections of content that the server streams to clients. Users perceive playlists as a single streaming experience. For more information, see "Sourcing from playlists" in Windows Media Services Help.
If you use a network management console, such as Hewlett-Packard HP OpenView, Compaq Insight Manager XE, and Dell OpenManage, you can receive events through Simple Network Management Protocol (SNMP) and Windows Management Instrumentation (WMI). With these events, you can keep apprised of server activity and react quickly to situations as they arise. For more information, see "Monitoring performance" in Windows Media Services Help.
NoteRegardless of the interface you use to access your server, you must have administrative rights and privileges for the server to manage it or change its settings. For more information, see "Limiting user rights" in Windows Media Services Help.
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Common tasksThis section contains the following end-to-end procedures for common server management tasks to help you get started quickly using Windows Media Services:
Stream Windows Media files on demandThis quick start section demonstrates how to use Windows Media Services to stream a single file from your server when a user requests it, also known as on-demand streaming. Users can start, stop, pause, fast-forward, and rewind the content they request by using controls on the player. From a user's perspective, on-demand streaming is similar to playing content on a DVD or CD player.
Windows Media Services requires no additional configuration and is ready for on-demand streaming. All you need to do is place the file that you want to stream in the default Windows Media Services content directory. The file can be either a Windows Media file or an .mp3 file.Double-click the My Computer icon, and then locate the file you want to stream. Copy the file to the %systemdrive%\Wmpub\WMRoot folder on your Windows Media server. Your server is now ready to stream the file.
For information about testing your streaming content, see "Testing a stream" in Windows Media Services Help.
NoteYou can use an announcement to direct users to your content. Announcements are metafiles that automatically open Windows Media Player and direct the Player to the content on a publishing point. For more information about announcements, see "Working with the announcement wizards" in Windows Media Services Help.
Use your server to publish live content from Windows Media EncoderThis quick start section demonstrates how to use Windows Media Services to stream live content that it pulls from a computer running Windows Media Encoder. The user experience is similar to watching a traditional television program or tuning into a radio broadcast. The user can watch or listen to the content, but does not have the ability to pause, fast-forward, or rewind it.
For this task, you must have a separate computer running Windows Media Encoder that has an audio or video capture card. The live stream is encoded from an attached video camera, VCR, or microphone.- On the computer running Windows Media Encoder, start encoding your live content by doing the following:
Start Windows Media Encoder and create a new broadcast session. Begin encoding the session and note the connection URL for the encoder. The connection URL has the following syntax: protocol://encoder:port (for example, http://encoder1:8080). This is the URL that the Windows Media server uses to connect to the encoder. For more information about setting up the encoder for a live broadcast, see Windows Media Encoder Help.
- Create a new broadcast publishing point on the Windows Media server by using the Add Publishing Point Wizard:
In the console tree, expand the server from which you want to stream the content, and then click the Publishing Points item. On the Action menu, click Add Publishing Point (Wizard).
- In the Add Publishing Point Wizard, do the following:
On the welcome page, click Next. On the Publishing Point Name page, type a name for the new publishing point. On the Content Type page, click Encoder. On the Publishing Point Type page, click Broadcast publishing point. On the Delivery Options for Broadcast Publishing Points page, click Unicast.
- Using the wizard, configure the following settings to enable the publishing point to receive content from the encoder:
On the Encoder URL page, type the encoder URL using the following syntax: http://encoder:port. On the Unicast Logging page, select the check box if you want to log data about your clients. On the Publishing Point Summary page, verify that the settings for the new publishing point are correct. On the Completing the Add Publishing Point Wizard page, select the Start publishing point when wizard finishes check box, clear the After this wizard finishes check box, and then click Finish.
Users can now connect to the live encoder stream by using the URL of your publishing point. The URL of a broadcast publishing point uses the following syntax: protocol://server/publishing_point (for example, mms://server1/my publishing point).
For information about testing your streaming content, see "Testing a stream" in Windows Media Services Help.
NotesYou can use an announcement to direct users to your content. Announcements are metafiles that automatically open Windows Media Player and direct the Player to the content on a publishing point. For more information about announcements, see "Working with the announcement wizards" in Windows Media Services Help.
Use your server to broadcast a stream published by Windows Media EncoderThis quick start section demonstrates how to publish a broadcast from a computer running Windows Media Encoder through a Windows Media server, also known as push distribution. This technique is ideal for broadcasting company meetings or live presentations. For this task, you must have a separate computer running Windows Media Encoder that has a sound card or video capture card and the appropriate input devices. Also, be sure that the person operating the encoder has administrator rights and privileges for the Windows Media server and can connect to Windows Media Services.- Prepare Windows Media Services to receive content from the encoder by doing the following:
In Windows Media Services, in the console tree, click the server from which you want to stream. In the details pane, click the Properties tab, and then in Category, click Control protocol. Click WMS HTTP Server Control Protocol, and then click the Enable button. Windows Media Encoder uses the HTTP control protocol to send the encoded stream to the Windows Media server. For more information, see "Using the HTTP protocol" in Windows Media Services Help. On the computer running Windows Media Encoder, set up a new encoding session to broadcast a live event.
Configure the encoder to create a new publishing point on your server by choosing the appropriate broadcast method. - You need to supply the following information to the encoder to enable it to create a publishing point successfully:
The name of your Windows Media server. The name of the publishing point from which the content will be broadcast. The encoder will create this publishing point on your server if it does not already exist. The name of an existing publishing point on the Windows Media server that has the settings that you want to use as a template for your new publishing point. The encoder administrator must have write and create permissions for the publishing point to use it as a template. If there is not an existing publishing point that you want to duplicate, the encoder will use the default publishing point configuration. For more information about setting publishing point permissions, see "WMS Publishing Points ACL Authorization" in Windows Media Services Help.
After Windows Media Encoder creates a broadcast publishing point on the Windows Media server and begins streaming live content to it, clients can connect to the broadcast by using the publishing point URL or an announcement file.
For information about testing your streaming content, see "Testing a stream" in Windows Media Services Help.
NotesWindows Media Services does not include a logging plug-in for encoder push scenarios. You can log encoder push broadcast data by creating an active script logging plug-in to use on your Windows Media server. For more information about creating a custom plug-in, see the Windows Media Services 9 Series Software Development Kit (SDK).
Use a playlist with on-demand Windows Media filesThis quick start section demonstrates how to stream a set of files in the order you specify. This streaming scenario is ideal for providing online training or a series of on-demand presentations. To set up this task, you need to identify a set of Windows Media files that you intend to stream as a playlist, and then use the following steps to accomplish the task:- Use the Add Publishing Point Wizard to create a new on-demand publishing point by right-clicking the server from which you want to stream a playlist and then clicking Add Publishing Point (Wizard). Proceed through the wizard pages making the following choices:
On the Publishing Point Name page, type a name for the new publishing point. On the Content Type page, click Playlist. On the Publishing Point Type page, click On-demand publishing point. On the Existing Publishing Point page, click Add a new publishing point. On the File Location page, click New Playlist.
- Use the wizard to create a new playlist by doing the following:
On the New Playlist page, click the Add Media button. The Add Media Elements dialog box appears. In Location of content, type the location of the content or click the Browse button to locate the content. Click OK. Repeat the previous step as necessary to add all of the files to the playlist. On the New Playlist page, adjust the sequence of the files in the playlist by clicking a file and then clicking the Move Up or Move Down buttons. On the Save Playlist File page, type a unique file name and location for your playlist.
- Use the wizard to enable and configure the following plug-ins:
WMS Playlist Transform plug-in
On the Content Playback page, select the appropriate check box if you want to loop or shuffle your playlist content. Select both check boxes for continuous, random playback. WMS Client Logging plug-in
On the Unicast Logging page, select the check box if you want to log data about your clients.
- Verify that your wizard settings are correct and complete:
On the Publishing Point Summary page, verify that the settings for the new publishing point are correct. On the Completing the Add Publishing Point Wizard page, clear all of the check boxes and then click Finish.
Users can now receive the content in the playlist by using the URL of your publishing point. The URL of a publishing point uses the following syntax: protocol://server/publishing_point (for example, mms://server1/my publishing point).
For information about testing your streaming content, see "Testing a stream" in Windows Media Services Help.
NotesYou can use an announcement to direct users to your content. Announcements are metafiles that automatically open Windows Media Player and direct the Player to the content on a publishing point. For more information about announcements, see "Working with the announcement wizards" in Windows Media Services Help. You can change the properties for a file in a playlist by modifying the properties area in the Playlist Editor or by using the Source tab. For more information about modifying playlist elements and attributes, see the Windows Media Services SDK Playlist Reference.
Alternate between live and prerecorded content in your broadcastThis quick start section demonstrates how to use Windows Media Services to stream both live and prerecorded (stored) content. Despite the inclusion of stored content, users do not have the ability to pause, fast-forward, or rewind the broadcast. The user has the option of starting, stopping, and resuming the broadcast stream, creating a user experience similar to tuning into a radio or television broadcast.
This quick start section is an example of how versatile server-side playlists can be and how they are used to manipulate the playback at the client computer. For this task, you must be streaming live content from a computer running an encoder and you must have prerecorded content, such as an advertisement, in a Windows Media file. In the following procedure, the client receives five minutes of live content, which is then is interrupted for an advertisement. When the advertisement ends, the live content resumes for another five minutes.In Windows Media Services, in the console tree, click Publishing Points. In the details pane, click the View playlist editor button. The Windows Media Playlist Editor opens. - Add container elements to the playlist to control how different playlist elements are played back with respect to each other. In this quick start, the publishing point will pause the content when one element interrupts another. To specify this behavior do the following:
In the Windows Media Playlist Editor, click the Add element arrow on the toolbar and then click Exclusive. An excl element appears in the playlist tree. Click the excl element that you just created. Click the Add element arrow on the toolbar and then click PriorityClass. A priorityClass element appears in the below the excl element. Click the priorityClass element that you just created. In the properties area, click the peers attribute and then type Pause in the text box. Press ENTER. This setting instructs the publishing point to pause this content whenever it switches to another media element.
- Add live content to the playlist by doing the following:
In the Windows Media Playlist Editor, click the Add element button on the toolbar. The Add Media Elements dialog box appears. Type the URL of the encoder stream by using the following syntax: http://encoder:port. Select the Add as a child element check box and then click OK. The media element appears in the playlist tree beneath the priorityClass element and displays the URL of the encoder.
- In the Windows Media Playlist Editor, set the following values to define how the live content should be played back. In this example, the content will start immediately and stream for 10 minutes:
In the playlist tree, click the media element that you added in the previous step. Click the begin attribute in the properties area and then type 0 in the text box. Press ENTER. This setting instructs the publishing point to begin streaming the live content when the publishing point starts. Click the dur attribute in the properties area and then type 10min in the text box. Press ENTER. This setting instructs the publishing point to stream the live content for a total of 10 minutes.
To provide a unique identifier for the live content, click the id attribute in the properties area and then type a name for the media element, such as M1, in the text box. Press ENTER. This setting provides this media element with a name that can be referenced by other elements in the playlist. - Add prerecorded content to the playlist by performing the following steps. In this example, the prerecorded content is an advertisement:
In Windows Media Playlist Editor, click the priorityClass element in the playlist tree. Click the Add element button on the toolbar. The Add Media Elements dialog box appears. Type the name and location of the advertisement that you want to add. Select the Add as a child element check box and then click OK.
- Define how the advertisement should be played back by doing the following. In this example, the advertisement starts five minutes after the content starts:
In the playlist tree, click the advertisement media element that you just added. Click the begin attribute in the properties area and then type M1.begin + 5min, for example, in the text box. Press ENTER. This instructs the publishing point to wait until the live content has played for five minutes and then play the advertisement.
Provide a unique identifier for the advertisement by clicking the id attribute in the properties area. Type a name for the advertisement, such as M2, in the text box. Press ENTER. This provides this media element with a name that can be referenced by other elements in the playlist. Save the playlist and then close the Windows Media Playlist Editor. - Use the Add Publishing Point Wizard to create a new broadcast publishing point by doing the following:
On the Action menu, click Add Publishing Point (Wizard). The Add Publishing Point Wizard appears. On the welcome page, click Next. On the Publishing Point Name page, type a name for the new publishing point. On the Content Type page, click Playlist. On the Publishing Point Type page, click Broadcast Publishing Point. On the Delivery Options for Broadcast Publishing Points page, click Unicast.
- Use the wizard to reference the playlist that you created in steps 1 through 9 by using the following settings:
On the File Location page, click Existing playlist. In File name, type the name and location of the new playlist. On the Unicast Logging page, select the check box if you want to log data about your clients. On the Publishing Point Summary page, verify that the settings for the new publishing point are correct. On the Completing the Add Publishing Point Wizard page, clear all of the check boxes, and then click Finish.
- Configure the following publishing point settings to have the publishing point start when the first client connects:
In the console tree, click the publishing point you just created. In the details pane, click the Properties tab. In Category, click General. Click the Start publishing point when first client connects property and then click the Enable button.
Users can now receive the content in the playlist by typing the URL of your publishing point in their player. The URL to a publishing point uses the following syntax: protocol://server/publishing_point (for example, mms://server1/my publishing point).
For information about testing your streaming content, see "Testing a stream" in Windows Media Services Help.
Include interstitial advertising in your on-demand playlistThis quick start section demonstrates how to stream a playlist that contains prerecorded (stored) content and advertising. You can stream advertising content from either a locally-stored file or from a participating advertiser's server. This quick start section assumes that you have several prerecorded content files as well as some sort of advertising content available for streaming.- Use the Add Publishing Point Wizard to create a new on-demand publishing point by doing the following:
In Windows Media Services, in the console tree, expand the server from which you want to stream content. On the Action menu, click Add Publishing Point (Wizard). On the welcome page of the Add Publishing Point Wizard, click Next. On the Publishing Point Name page, type a name for the new publishing point. On the Content Type page, click Playlist. On the Publishing Point Type page, click On-demand Publishing Point.
- To use the wizard to create a new playlist, do the following:
On the New Playlist page, click the Add Media button. The Add Media Elements dialog box appears. In Location of content, type the location of the digital media content or click the Browse button to locate the content. Click OK. Repeat the previous steps as necessary to add all of the content to the playlist. On the New Playlist page, adjust the sequence of the files in the playlist by clicking a file and then clicking the Move Up or Move Down buttons.
- Use the wizard to add advertising content to the playlist by doing the following:
On the New Playlist page, click the Add Advertisement button. The Add Advertisement dialog box appears. Type the location of the advertising content or click the Browse button to locate the advertisements. Click OK. Repeat the previous steps as necessary to add all of the advertisements to the playlist. On the New Playlist page, adjust the sequence of the files in the playlist by clicking a file and then clicking the Move Up or Move Down buttons. On the Save Playlist File page, type a unique file name and location for your playlist.
- Use the wizard to configure the following playback options:
On the Content Playback page, select the appropriate check box. On the Unicast Logging page, select the check box if you want to log data about your clients. On the Publishing Point Summary page, verify that the settings for the new publishing point are correct. On the Completing the Add Publishing Point Wizard page, clear the After this wizard finishes check box, and then click Finish.
Users can now receive the content in the playlist by typing the URL of your publishing point in their players. The URL of a publishing point uses the following syntax: protocol://server/publishing_point (for example, mms://server1/my publishing point).
For information about testing your streaming content, see "Testing a stream" in Windows Media Services Help.
To see how many advertisements have been served by this publishing point at any time, in the details pane, click the Advertising tab. In the Advertisements served by area, click the Reset button to restart the count at zero.
Use wrappers to provide advertising with your live broadcastThis quick start section demonstrates how to append advertising to the beginning and end of a live broadcast using wrappers. Wrappers are a special type of playlist that can be used to reference ads and other content that precede or follow user-requested content, or both. Wrappers commonly include introductory pages that generate custom playlists, site branding, and sponsor identification. Wrappers are especially effective when used with live streaming because they ensure that the audience will view the advertising content no matter when they join the broadcast. The source of advertising content can be either a locally-stored file or a link to a participating advertiser's server.
You have the option of starting, stopping, and resuming the broadcast stream based on one or more user connections, but the user experience will be similar to tuning in to a radio or television broadcast. Live content viewers do not have the ability to pause, fast-forward, or rewind the content of a broadcast and will join the broadcast in process.
In this quick start, it is assumed that you have another computer running Windows Media Encoder that is broadcasting a live stream and that you have prerecorded advertising content available. This quick start section uses the Create Wrapper Wizard to create a wrapper that streams the prerecorded advertising content before and after the live broadcast. It does not specifically address setting up a live stream. For a detailed description of how to set up Windows Media Encoder, see Windows Media Encoder Help.- Do the following to start the Create Wrapper Wizard:
In Windows Media Services, in the console tree, expand the server from which you want to stream content, and then expand Publishing Points. Click the broadcast publishing point in which you want to include a wrapper. In the details pane, click the Advertising tab. Click Wrapper Editor to open the Wrapper Playlist Editor Options dialog box. Click Create playlist file, and then select the Use the Create Wrapper Wizard check box. The Create Wrapper Wizard appears.
- Use the following settings in the Create Wrapper Wizard to add advertising content to your wrapper playlist:
On the welcome page, click Next. On the Wrapper Playlist File page, click the Add Advertisement button. The Add Advertisement dialog box appears. Type the location of the advertising content or click the Browse button to locate the advertisements. Click OK. Repeat the previous steps as necessary to add all of the desired wrapper advertisements. Change the location of the wrapper ads before by clicking an individual item and then clicking the Move Up or Move Down buttons. On the Save Wrapper Playlist File page, type a unique file name and location for your wrapper playlist. Select the Start publishing point when wizard finishes check box to reset the publishing point, allowing all enabled wrappers to play as scheduled. Select the Enable wrapper playlist when wizard finishes check box to use the new wrapper playlist immediately, and then click Finish.
For information about testing your streaming content, see "Testing a stream" in Windows Media Services Help.
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Streaming terminologyWhen using the administrative interfaces, it is helpful to have an understanding of some specialized terms and concepts that are used when working in a streaming media environment. The following list is meant to give you a quick overview of these terms and concepts:
Announcement file
An announcement file is a Windows Media metafile with an .asx file name extension that is used to redirect clients to content on your Windows Media server. Announcement files can be distributed to clients from a Web site, sent as an e-mail attachment, or shared on network drive. By default, the announcement file is associated with Windows Media Player. The announcement file uses Extensible Markup Language (XML) syntax and can contain additional information to be displayed in the Player, such as file properties and captioning information. The announcement file can also contain additional instructions for the Player, such as instructions to open a Web page or to send logging data to a server.
In the Windows Media Services snap-in, you can create announcement files by using the Unicast Announcement Wizard. If you are using multicast transmission, you can create an announcement file when you create a multicast information file by using the Multicast Announcement Wizard.
Bandwidth
Bandwidth is a measurement that reflects the data transfer capacity of a network. Bandwidth is usually expressed in the number of bits that a system is capable of transferring in a second: bits per second (bps) or kilobits per second (Kbps). Windows Media Services utilizes the available network bandwidth when streaming content to clients. Each stream from your server has a bandwidth requirement. Clients that are connecting to your server have defined available bandwidth, based on their network connection method. Therefore, when planning your streaming media system, you must include support for different bandwidths. Multicasting streaming is one method that is commonly used to conserve bandwidth on intranets because it only sends a single stream across the network.
Broadcast
Broadcast is a means of transmitting data to a large audience simultaneously. In Windows Media Services, broadcasts are accomplished through the use of broadcast publishing points. Clients that receive a broadcast cannot control the start of the content or the rate of playback, and they cannot fast-forward or rewind the stream. The server is in control of the stream. Before clients can receive content from a broadcast publishing point, the publishing point must be started.
Content
Content is a generic term that refers to any audio, video, images, text, or other information that is contained in a digital media file or stream. You can then use the content as a source for your publishing point and stream the content across a network using Windows Media Services.
Cue
Cueing is a means of preloading content from a broadcast playlist into the memory of the server so that it can be transmitted to clients with less delay. By default, the next item in a playlist sequence is cued when the previous content is 90 percent complete. If you are going to skip a playlist entry during a broadcast, cueing the entry first provides a better playback experience. Cueing an element in a playlist can be done from the Source tab of the publishing point that is broadcasting the content.
Distribution
Distribution describes the process by which content is transmitted from one computer to another. You can use the following types of distribution with Windows Media Services:Server-to-server distribution. This occurs when a publishing point on your server acts as the content source for a publishing point on another Windows Media server, which then transmits the content to players that request it. Push distribution. This occurs when an encoder initiates a broadcast and then uses a publishing point on a Windows Media server to transmit the content to the players that request it. Pull distribution. This occurs when a server initiates a connection to an encoder to receive a content stream and then transmits the content to the players that request it.
Element
Element is an XML term that refers to the "building blocks" of a playlist. When used in a playlist file, elements can define timelines, create groups of content, and define how the different pieces of the playlist interact with each other.
Encoder
An encoder is a computer which uses software, such as Windows Media Encoder, to apply a compression/decompression algorithm (or codec) and stream format to content that is in either analog or digital audio and video format and then reproduces the content as a digital file or stream. This process is referred to as encoding. After the content has been encoded, it can be distributed by Windows Media Services. In most cases, the software used to encode the content is installed on a separate computer from Windows Media Services.
File location
The file location explains how and where Windows Media Services can locate the file you specify. The location can be specified as either an explicit path, such as C:\WMPub\WMRoot\file.wma, a URL address, such as http://server/file.wma, or a network resource path, such as \\server\folder\file.wma.
Interstitial advertisements
Interstitial advertisements are advertisements that occur in the middle of the content that the user is receiving.
Logging
Logging is the process of writing data about the activity of your server and its clients to a file.
Loop
A loop is the continuous repetition of content streaming from a publishing point on your server. When content is looped, it plays from beginning to end and then starts over at the beginning without any perceptible wait time. The WMS Playlist Transform plug-in must be enabled for the server to loop the content in your playlist or directory. Looping can be turned off and on through the properties sheet of the WMS Playlist Transform plug-in.
Multicast
Multicast is a method of transmitting data across a network that allows many clients to receive the same data stream. This minimizes the amount of bandwidth required to transmit the data to a group of network clients. Multicast transmission requires that the routers and switches on the network be multicast-enabled, which means that they can transmit class-D IP addresses and interpret multicast information packets.
Note
On-demand
On-demand describes a method of delivering content that uses unicast transmission to stream the content only when the client requests it from the server. Each client that requests a stream usually has full control of the stream and can fast-forward, rewind, pause, and restart the content. This is because on-demand publishing points provide a unique data path for every client that requests content.
Playlist file
A playlist file can be used by Windows Media Services to stream a sequence of content, such as digital media files, encoder URLs, and other content server locations, to users from a publishing point. Playlist files can be either server-side or client-side. Server-side playlist files allow you to manage the playlist on the server while clients are receiving the content. Client-side playlists are transferred to the player, which then manages all of the content items. In client-side playlists, content references cannot be modified by the server.
Plug-in
Plug-ins are used by Windows Media Services to enable different features. Plug-ins are managed along with the other configurable properties of your server through the Properties tab in the administrative interfaces. You can use plug-ins purchased from other software vendors and custom plug-ins created by using the Windows Media Services 9 Series SDK to extend the functionality of Windows Media Services.
NotesCustom or third-party plug-ins should be located in a protected directory to prevent tampering. The protected directory can be any directory that has been set to deny write permissions to unauthorized users. For more information about restricting directory access, see Windows Help and Support. Installation of custom or third-party plug-ins is not available if Windows Media Services 9 Series is running on the Microsoft Windows Server 2003, Standard Edition or Windows Server Code Name "Longhorn" Standard operating systems..
Port
A port identifies a unique process through which a server can provide a service or a client can access a service. Windows Media Services uses both Transmission Control Protocol (TCP) ports and User Datagram Protocol (UDP) ports to stream content.
Publishing point
A publishing point is the means by which you distribute your content to users. Content can be published by creating an announcement file that redirects clients to your publishing point or by distributing the URL to your publishing point.
Pull
Pulling is one of the methods by which content is transmitted from a stream source, such as Windows Media Encoder or another Windows Media server, to the Windows Media server that is requesting it. Pull is used to denote that the transmission of the stream is initiated and managed by the requesting server.
Push
Pushing is one of the methods by which content is transmitted from Windows Media Encoder to a Windows Media server. Push is used to denote that the transmission is initiated and managed by the encoder.
Shuffle
Shuffle is a method of randomizing the content referenced either by a directory or playlist file before streaming it from your publishing point. When content is shuffled, it plays each item in the playlist or directory once in a random order. Shuffle can be used with looping to provide continuous, random playback. The WMS Playlist Transform plug-in must be enabled for the server to shuffle the content in your playlist or directory. Shuffle can be turned off and on through the properties sheet of the WMS Playlist Transform plug-in.
Streaming
Streaming is a means of transmitting digital media in packets that can be rendered as they are received, allowing for the playback of data in a continuous flow without the delay required to download an entire file.
Unicast
Unicast is a method of transmitting data packets on a network that requires point-to-point communication between the client and the services transmitting the data. Unicast is also known as directed traffic, because the data is directed to a specific client on the network.
Windows Media file
A Windows Media file is a file containing audio, video, or script data that is stored in Windows Media Format. Depending on their content and purpose, Windows Media files use a variety of file name extensions, such as: .wma, .wme, .wms, .wmv, .wmx, .wmz, or .wvx.
WMRoot
WMRoot is the Windows Media root directory. Windows Media Services creates this folder by default during setup. In it you will find sample content files, a sample playlist file, and a sample wrapper playlist that you can use to learn about Windows Media Services. The Default publishing point uses %systemdrive%\WMPub\WMRoot as its source. After Windows Media Services is running on your server, you can use a player to connect and view the sample content by using the following URL: mms://server/content_clip1.wmv.
You can place any existing content you have into WMRoot and quickly start streaming content.
Wrapper playlists
Wrapper playlists are Windows Media metafiles that add additional content to the beginning or end of a stream. Examples of content include welcome or goodbye messages, advertisements, and station branding. In the Create Wrapper Wizard, the content of the publishing point is represented by %Content requested by client%. In the wrapper playlist file, the content of the publishing point is represented by %requestedURL%.
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For more informationThis section provides a reference list of other sources of information for troubleshooting and deploying Windows Media Services.Windows Media Home Page. This Web site is your window to all of the Windows Media Technologies and links to related information, including an extensive collection of books, articles, videos, and technical documents that showcase Windows Media tools and technologies. Windows Media Developer Center. This Web site pulls together the content and resources for Windows Media technologies, including code samples, community sites, technical articles and documentation, upcoming events, and much more.
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