Windows Media Encoder

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Windows Media Encoder

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Windows Media Encoder

Getting started

Encoding with quick starts or the New Session Wizard

Using quick starts to encode

Using the New Session Wizard to encode

What's new

Feature requirements

Hardware and software requirements

About encoder views

About the encoder utilities

Documentation conventions

Concepts

Understanding codecs

About sessions

Comparing Windows Media servers and Web servers

About CBR or VBR encoding

About one- or two-pass encoding

Configuring sources

Sourcing from a file

Sourcing from multichannel audio files

Sourcing from devices

Enabling device control

Setting up an EDL

Capturing screens

Improving performance when encoding screens

Inserting script commands

Using multiple sources in a session

Customizing a session

Cropping and resizing video before encoding

Preserving the pixel aspect ratio of video

Optimizing video and audio

Deinterlacing or maintaining the interlacing in video

Applying the inverse telecine filter to video

Optimizing audio for voice

Specifying a language for content

Applying time compression to your content

Using CBR encoding

Using VBR encoding

Setting up an MBR stream

Using digital rights management to protect content

Setting up an account with a license provider

Embedding a watermark in content

Using hardware profiles

Hardware profiles for video

Using transform plug-ins

Output options

Encoding or archiving a broadcast to a file

About the .asf, .wma, and .wmv file name extensions

Encoding uncompressed audio and video files

Broadcasting content live

Pushing a stream from the encoder

Creating an announcement for a multicast

Enabling clients to pull a stream from the encoder

Restricting access to a broadcast

Testing your content

System configuration options

Security and Windows Media Encoder

Achieving optimal system performance

Adjusting encoder performance settings

Best practices for compression settings

Running multiple encoders on one computer

Accessibility for people with disabilities

Accessibility features in Windows Media Encoder

Using keyboard shortcuts

Accessibility features in Windows Media Encoder Help

Keyboard shortcuts for using the Help window

Accessible products and services from Microsoft

Accessibility in Microsoft Windows

Adjusting Microsoft products for people with accessibility needs

Free step-by-step tutorials

Microsoft documentation in alternative formats

Assistive technology for Windows

Customer service for people who are deaf or hard-of-hearing

Getting more accessibility information

Glossary

Windows Media Encoder

Microsoft® Windows Media® Encoder 9 Series is a powerful production tool for converting both live and prerecorded audio and video into Windows Media files or streams. The following sections introduce conceptual information about the encoding process and provide steps for using Windows Media Encoder.

Getting started. Explains how you can set up an encoding session in a few short steps by using quick starts or the New Session Wizard. Also describes changes to Windows Media Encoder, describes the system requirements, and provides information about the various panels that make up the user interface.

Concepts. Provides general information about working with the encoder.

Configuring sources. Provides information about the input sources supported by the encoder, including files, devices, screens, and script commands.

Customizing a session. Describes how to configure a new encoding session or customize an existing session to meet your needs.

Output options. Describes the output options available to you when encoding: encoding to a file or broadcasting a live event (by using either push or pull distribution).

System configuration options. Describes system configuration options, including security for the encoding computer, running multiple instances of the encoder on a computer, batch encoding, and the steps you can take to achieve optimal system performance.

Frequently asked questions and troubleshooting. Provides a link to the Microsoft Web site where you can find suggestions for resolving issues that might arise when using the encoder.

Technical support options. Lists phone numbers and Web sites that you can use if you require additional support.

Accessibility for people with disabilities. Provides information about features, products, and services that make Windows Media Encoder more accessible for people with disabilities.

Glossary. Provides definitions and terms related to the encoder.

Getting started

This section includes information about how you can set up an encoding session in a few short steps by using quick starts or the New Session Wizard. It also includes information about what is new in this version of Windows Media Encoder, feature requirements, hardware and software requirements, and describes the various panels that make up the encoder interface.

Encoding with quick starts or the New Session Wizard

Before encoding content, you must set up an encoding session. The easiest way to do so is to use quick starts or the New Session Wizard. Quick 20120o1422u starts are session files that are included with Windows Media Encoder. They are designed to address common encoding scenarios and already include most of the settings you need to begin encoding without delay. All you need to do is provide specifics about your content, such as file names or server names. You can also use the New Session Wizard, which walks you through the steps necessary to set up four of the most common encoding scenarios.

The quick starts and wizard are available from the New Session dialog box (if enabled) that is displayed when you first open the encoder or from the main encoder window by clicking New Session on the toolbar.

After you set up your encoding session, you are ready to encode content. If you plan to run the same session again, you can save the settings to a session file and then use the session at a later date. Session files are saved with a .wme extension.

Using quick starts to encode

Quick starts are session files that are included with Windows Media Encoder. They are designed to address common encoding scenarios and already include most of the settings you need to begin encoding without delay. All you need to provide is specifics about your content, such as file names or server names.

The available quick starts include:

Capture live content for local playback. Captures live content from audio and video devices and encodes it to a file. You can distribute the content so users can download and play it locally.

Capture live content for streaming. Captures live content from audio and video devices and encodes it to a Windows Media file.

Convert film content to video. Converts file-based content that originated on film to Windows Media Format so users can download and play it locally.

Broadcast company meeting Pushes a stream to a publishing point on a server running Microsoft Windows Media Services.

If you have a session that you want to use frequently, you can add it to the list of quick starts.

Note

To launch the quick starts, on the toolbar, click New Session, click the Quick Starts tab, and then click a quick start.

Using the New Session Wizard to encode

The New Session Wizard walks you through the steps necessary to set up four of the most common encoding scenarios. The four common encoding scenarios are:

Broadcast a live event. Captures audio or video from devices installed on your computer and then broadcast the content live, either by pushing the stream to a server running Microsoft Windows Media Services or by enabling Windows Media servers and players to pull the stream directly from the encoder.

Capture audio or video. Captures audio or video from devices installed on your computer and then convert the captured content to a Windows Media file for later distribution.

Convert file. Converts an audio or video file to Windows Media Format for later distribution.

Capture screen. Captures screen images, including mouse pointer movements, on the computer. You can capture the entire screen, a region of the screen, or a specific window.

To change session properties, you can either run the New Session Wizard again or use the Properties panel to edit your settings. If you plan to reuse the session, save your settings in a session file.

Note

To open the New Session Wizard, on the toolbar, click New Session, and then click one of the four wizards. You can use Custom session to set up a custom encoding session.

What's new

Windows Media Encoder 9 Series includes enhancements that are both powerful and easy to use. This section summarizes the changes to the encoder for this release.

Targeting various encoding scenarios has been made easier with the addition of new destinations. In addition, four quick starts are available that help you begin encoding without delay. Each quick start is designed to address a common encoding scenario.

New codecs have improved the quality of encoded audio and video content.

Support for dragging source files and session files to the encoder window makes it easy to begin encoding quickly.

New constant-bit-rate (CBR) and variable-bit-rate (VBR) encoding modes enable you to fine-tune settings depending on the playback scenario you are targeting.

A device control feature enables you to run devices directly from the encoder. (The device must be connected to an IEEE 1394 digital video port, or you can use a video tape recorder (VTR) that supports the Sony RS422 protocol and that is connected through a COM port.) You can also use the built-in edit decision list (EDL) to arrange and encode clips in any order.

Multichannel audio encoding is available through the Windows Media Audio 9 Professional and Windows Media Audio 9 Lossless codecs.

Digital rights management (DRM) is available for you to protect encoded content.

New push distribution feature helps you to initiate the connection with a Windows Media server from the encoder.

Language support lets you specify the language of your content.

Four utilities are included to provide additional features such as creating custom profiles, splitting and combining streams in different files, and indexing files after encoding.

Temporary storage of content to hard disk helps you to ensure the quality of encoded content.

Support of transform plug-ins enables developers to write plug-ins that modify audio and video content, which you can use to add special effects during encoding.

Support for sourcing from additional file formats has been implemented.

Support for nonsquare pixel output helps you to encode letterboxed content while maintaining the aspect ratio of the source video.

Frame-level seeking can be implemented by creating or preserving time codes for some sources.

Multiple bit rate (MBR) content now supports multiple audio formats and video resolutions.

Support for the Microsoft Windows® XP Plug and Play feature enables devices to be automatically detected by the encoder when running. In addition, the encoder is automatically launched when a new device is connected to the computer.

Feature requirements

The following table provides information about the Windows Media Encoder features that have specific Microsoft Windows Media Player, operating system, or codec requirements.

Feature	Windows Media Player			Operating systems	Codecs
	6.4	7.1/Windows XP	9 Series
Interlaced output video			X	Microsoft Windows XP	Windows Media Video 9
Nonsquare pixel output			X
Multiple-resolution MBR content			X
MBR audio			X
DRM support	X	X	X
Multichannel audio			X	Microsoft Windows XP	Windows Media Audio 9 Professional or Windows Media Audio 9 Lossless
High-resolution audio (24-bit, 96 kHz)¹			X	Microsoft Windows XP	Windows Media Audio 9 Professional
Dynamic range control			X	Microsoft Windows XP	Windows Media Audio 9 Professional
CBR encoding (one- or two-pass)	X	X	X		See the following table
Quality-based VBR		X	X		See the following table
Bit rate-based VBR		X	X		See the following table
Peak bit rate-based VBR		X	X		See the following table

1 Earlier players or operating systems will render 16-bit, 48-kHz content

Note that content encoded with the Windows Media Audio and Video 9 Series codecs (except for the Windows Media Audio 9 codec) is not supported in Windows Media Player version 6.4. For Windows Media Player version 7.1 and Windows Media Player for Windows XP, content encoded with any of the codecs requires users to download the codec before playback. Content encoded using VBR encoding with the Windows Media Audio 9 codec may have glitches or silence during playback in Windows Media Player version 6.4. For Windows Media Player version 7.1 and Windows Media Player for Windows XP, content encoded with the Windows Media Audio 9 codec does not require a user to download the codec.

The following table lists the supported encoding methods for the codecs that are included with the encoder.

Codec	One-pass CBR	Two-pass CBR	Quality-based VBR	Bit rate-based VBR	Peak bit rate-based VBR
Windows Media Audio 9 Professional	Yes	Yes	Yes	Yes	Yes
Windows Media Audio 9 Lossless	No	No	Yes	No	No
Windows Media Audio 9	Yes	Yes	Yes¹	Yes¹	Yes¹
Windows Media Audio 9 Voice	Yes	No	No	No	No
Windows Media Video 9	Yes	Yes	Yes	Yes	Yes
Windows Media Video 8.1	Yes	Yes	Yes	Yes	Yes
Windows Media Video 7	Yes	Yes	Yes	Yes	Yes
Windows Media Video 9 Screen	Yes	No	Yes	No	No

1 Some glitches or silence may occur during playback in Windows Media Player version 6.4.

Hardware and software requirements

You can find up-to-date information about hardware and software requirements at several Web sites:

For information about system requirements, see the system requirements page at the Microsoft Web site

For a list of supported audio and video capture cards, see the hardware providers page at the Microsoft Web site.

For a list of supported portable devices, see the portable devices page at the Microsoft Web site.

About encoder views

The main window of Windows Media Encoder has numerous panels that provide information about the current session. The panels that are displayed when you encode depend on the type of content being encoded, the number of sources set up for the current session, and your personal preferences. You can display additional panels or hide the ones that are displayed. Any changes you make to the window are saved between sessions.

Properties panel. Includes properties that you can use to adjust the settings related to the current session or to set up a custom session.

Video panel. Displays the content you are encoding. Depending on the type of content, you can customize the window to show just the pre-encoded content, the encoded content, or both. In some instances, the source content or encoded output is not displayed during encoding.

Sources panel. Lists each source in the current session. You can switch between sources while encoding by clicking the appropriate source button.

Audio panel. Contains controls for monitoring and adjusting the volume of the audio stream you are encoding.

Device panel. Appears when you have a device connected to your computer either through an IEEE 1394 port or a COM port using a video tape recorder (VTR) that supports the Sony RS422 protocol. You can control the play, pause, stop, fast-forward, rewind, and eject functions of your device in this panel. You can also create an edit decision list (EDL) to automatically encode specific time segments of your content on one or more video tapes.

Monitor panel. Contains status information about the session.

Script panel. Appears if you enabled scripts as a source type when you set up the current session. You can insert a script command into the stream during encoding from this panel.

To display or hide a panel, on the View menu, click the panel you want to display or hide.

About the encoder utilities

Four utilities are included with Windows Media Encoder:

Windows Media Profile Editor. Use to create custom profiles for use in encoding sessions.

Windows Media File Editor. Formerly called the Windows Media ASF Indexer, you can use this tool to edit a Windows Media file. For example, you can trim the start and end points of the file; add markers, and script commands; control the dynamic range of audio content; and, for multichannel audio files, control how the channels are folded down for stereo playback.

Windows Media Stream Editor. You can use this tool to split or combine streams in existing Windows Media files to create a file. For example, you can split an MBR file into multiple single-bit-rate files. Or, you can create multiple files, each with the same video stream but a different audio stream (for example, to create a single file with multiple languages).

Windows Media Encoding Script. Formerly called the Windows Media Encoding Utility, you can use this command-line utility (Wmcmd.vbs) to encode and broadcast content. This utility is installed in the same location as the encoder, which is C:\Program Files\Windows Media Components\Encoder by default.

Documentation conventions

The following conventions are used in this Help system.

This convention	Indicates
Bold	Text that appears in the user interface or should be typed into the user interface exactly as shown.
Italics	Placeholder text you should replace with text appropriate to your environment.
Code	Sample code you should replace with code appropriate to your environment.

Concepts

This section provides general information about working with Windows Media Encoder 9 Series.

Understanding codecs

Uncompressed audio and video content can consume a lot of bandwidth when streaming or create large files. By compressing the content, it can be broadcast over common Internet bandwidths or saved to a Windows Media file of a reasonable size. You can compress content by applying compression algorithms to the data, taking into account the desired output quality and available bandwidth. Before the content is played, it is decompressed by using decompression algorithms. These compression and decompression algorithms are called codecs. The following table provides more detailed information about the codecs available in Windows Media Encoder.

Codec	Description
Windows Media Audio 9 Professional	Provides a full surround sound experience and dynamic range control. Intelligently folds down multichannel audio to 2 (stereo) or 1 (mono), depending on the speaker configuration of the playback device. Intended for data rates of 128 to 768 Kbps.
Windows Media Audio 9 Lossless	Provides lossless encoding of audio content. Supports multichannel audio encoding and dynamic range control.
Windows Media Audio 9	Provides a 20 percent improvement in compression over the Windows Media Audio 8 codec. Supports VBR audio encoding.
Windows Media Audio 9 Voice	Offers superior quality for audio content with a voice emphasis. Provides for mixed-mode encoding of voice and music. Intended for playback at bit rates at 20 Kbps or lower.
Windows Media Video 9	Creates high-quality video for streaming, download-and-play, and physical format delivery scenarios. Provides a 15 to 50 percent improvement in compression over the Windows Media Video 8.1 codec, with the more significant improvement occurring at higher bit rates. Enables playback of interlaced content on televisions and set-top boxes.
Windows Media Video 8.1	Supports a wide variety of network bandwidths. Deinterlaces interlaced content before encoding.
Windows Media Video 7	Enables users of Windows Media Player 7 to view encoded video content without first having to download the latest codecs. Best choice when the encoding computer cannot support the performance requirements of the newer Windows Media Video codecs.
Windows Media Video 9 Screen	Provides improved handling of shaded images, screen motion, and scrolling for screen captures. Supports one-pass CBR and VBR encoding with no frame dropping. This codec is fully optimized for both streaming and download-and-play scenarios.

Note

In some instances, the Sipro Labs ACELP codec appears in the list of codecs. For example, if you import a profile that was created by using Windows Media Encoder version 7.1. If this occurs, it is recommended that you use the Windows Media Audio 9 Voice codec instead.

About sessions

Before you can encode, you must set up an encoding session. As part of setting up the session, you must do the following:

Specify the source of your audio or video content. You can source from devices, files, or both devices and files. You can also capture screens directly from your desktop.

Choose the output option. Select whether to broadcast the content or encode it to a file. If you broadcast the content, you can push the stream to a Windows Media server, and you can enable Windows Media servers and players to pull the stream from the encoder. You can also choose to archive a copy of the broadcast for later use.

In addition, you should check compression and quality settings before you encode. Default settings are applied, but it may be necessary to adjust the settings to meet your needs. For example, if you are planning to distribute your content for download-and-play on a computer, you may want to use bit rate-based VBR encoding and set the video and audio quality level to the higher bit rate.

After you have identified the source of your content and specified the output, you have a number of options for customizing a session. For example, you can optimize audio and video to improve the quality of the encoded content.

After configuring the session to meet your needs, you can start encoding. If you want to run the same session again, you can save the session to a session file either before or after you encode.

Note

It is not necessary to create a session each time you encode. The encoder includes quick starts and the New Session Wizard, which address common encoding scenarios.

Comparing Windows Media servers and Web servers

You can deliver content from a server running Windows Media Services or from a Web server to a player. The server and player can be either on the Internet or an intranet, and they can be separated by a firewall. Although 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, you should be aware of the differences in the way the content is delivered, which can affect the quality of the playback.

Windows Media servers

A Windows Media server meters the delivery of packets according to feedback information it receives while sending a stream to a player. 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 concurrently to your site and receive streams that are free of interruptions.

If you plan to deliver your content as a unicast stream from a Windows Media server, you can encode a multiple-bit-rate (MBR) stream. This provides users with better quality content during times of network congestion. When MBR content is received by a player, only the bit rate that is the most appropriate for network bandwidth conditions is streamed. The process of selecting the appropriate stream is handled by the Windows Media server and the player and is invisible to the user.

When streaming single-bit-rate streams or files, a Windows Media server is designed to handle network congestion smoothly. If congestion occurs during the broadcast, the stream is "thinned", which means that the frame rate is reduced. If this is insufficient, the video portion of the stream is frozen and only the audio portion is streamed.

Web servers

A Web server is designed to download as much data as it can, as quickly as possible. This is the preferred method for sending packets containing static images, text, and Web page script, but it is not the best method for sending packets containing streaming media. Streaming media should be delivered in real time, not in large bursts, and the player should receive packets just ahead of rendering them.

Web servers do not support MBR streams. When a file streams from a Web server, the quality of the delivery is not monitored and no adjustment to the bit rate can be made. Web servers cannot use the preferred delivery protocol, User Datagram Protocol (UDP), so the delivery of a stream is more likely to be interrupted by periods of silence while the player buffers data. In addition, Web servers do not support live broadcasts and multicast streams.

Note

Windows Media Services 9 Series in Windows Server 2003 includes several features, called Fast Streaming, which can combine some of the advantages of downloading and streaming. For more information about Fast Streaming, see Windows Media Services Help.

About CBR or VBR encoding

Using Windows Media Encoder, you can encode audio and video content at either a constant bit rate (CBR) or a variable bit rate (VBR).

CBR encoding

CBR encoding is designed to work most effectively in a streaming scenario. With CBR encoding, the bit rate remains fairly constant and close to the target bit rate over the course of the stream, within a small window of time set by the buffer size. The disadvantage of CBR encoding is that the quality of the encoded content is not constant. Because some pieces of content are more difficult to compress than others, some parts of a CBR stream are of lower quality than others. In addition, CBR encoding results in inconsistent quality from one stream to the next. In general, quality variations are more pronounced at lower bit rates.

VBR encoding

Use VBR encoding when you plan to distribute the content for downloading and playing either locally or on a device that has a constrained reading speed, such as a CD or DVD player. (You can also use the peak VBR encoding mode when you plan to stream the content.) VBR encoding is most advantageous when encoding content that is a mix of simple and complex data, for example, a video that switches between slow and fast motion. With VBR encoding, fewer bits are automatically allocated to less complex portions of the content, leaving enough bits available to produce good quality for more complicated ones. This means that content that has consistent complexity (for example, a "talking head" news story) would not benefit from VBR encoding. When used on mixed content, VBR encoding produces a much better encoded output given the same file size when compared to CBR encoding. In some cases, you can end up with a VBR-encoded file that has the same quality as a CBR-encoded file in half the file size.

Encoding mode options

With CBR encoding, you can use one- or two-pass encoding. You have three VBR encoding options: quality-based VBR (one-pass), bit rate-based (two-pass), and peak bit rate-based VBR (two-pass). Not all codecs support two-pass CBR encoding or VBR encoding.

About one- or two-pass encoding

With Windows Media Encoder, you can do one- or two-pass encoding, either with CBR or VBR encoding. (The quality-based VBR encoding mode is one-pass; the bit rate-based and peak bit rate-based VBR encoding modes are two-pass.)

With one-pass encoding, the content passes through the encoder once, and compression is applied as the content is encountered. With two-pass encoding, the content is analyzed during the first pass, and then encoded in the second pass based on the data gathered in the first pass. Two-pass encoding can result in better quality content because the encoder takes its time to find the optimal combination of bit rate, frame rate, buffer size, and image quality based on the scene composition. However, two-pass encoding takes longer because the encoder goes through all of the content twice.

Two-pass encoding is not available in the following situations:

The stream is broadcast

There are multiple sources in a session

The source is set to loop

Script commands are included in the stream

Source content is from devices, unless you have enabled device control

The source file has a .bmp file name extension

In addition, two-pass encoding is only available with certain codecs. For a list of the codecs that support two-pass encoding, see Feature requirements.

Note

If you are using two-pass encoding, you will not see the output video in the encoder during the first pass.

Configuring sources

Using Windows Media Encoder, you can encode live content in real time, stored content, or capture screens. Real-time sources of content include anything that you can plug into your audio or video card, including a CD player, microphone, VCR, video camera, video player, or television. Stored sources are audio or video files. You can also capture screens directly from your desktop, and insert script commands while encoding.

Keep in mind that the higher the quality of the source content, the higher the quality of the output content. This means that you should start with the highest quality source file or, if sourcing from devices, set your device to capture the highest quality possible.

When configuring a source, you first identify the source types (audio, video, or script) that make up the source. A source must consist of at least one audio or video source type. You can add an unlimited number of sources to an encoding session, either before or after encoding begins, but each subsequent source is based on the combination of source types you created in the session. For example, if your first source contained only audio, then all subsequent sources in the session are based on audio only. For multisource sessions, it is recommended that you configure your first source to use all three source types. If additional sources do not use a source type, you can encode a blank stream for that source type.

Sourcing from a file

Using Windows Media Encoder, you can source from files with .wma, .wmv, .asf, .avi, .wav, .mpg, .mp3, .bmp, and .jpg file name extensions. (Sourcing from a file with a .mpg file name extension requires a compatible MPEG-2 decoder on the encoding computer.)

If you are encoding a Windows Media file, any header attributes associated with the file (for example, markers, script commands, and so on) are lost in the process. You can use Windows Media File Editor to add the following attributes back to the file: title, author, copyright, and description.

When sourcing from a file, you can trim the start and end times of the file to ensure that you encode only the part of the file you want.

For more information about obtaining an MPEG-2 decoder, see the Microsoft Web site.

Note

Files that contain images with odd-sized dimensions are not supported. For example, an image that is 300 × 321 pixels is not supported, but an image that is 300 × 320 pixels is supported.

Sourcing from multichannel audio files

Using Windows Media Encoder, you can encode multichannel audio, which means you can encode audio for a surround sound playback in six (5.1 audio) or eight (7.1 audio) channels. The format is specifically designed for CD, DVD, high definition television, and digital cinema audio programs. Your content source must be one of the following:

A single 6-channel or 8-channel file that has a WAVE_FORMAT_EXTENSIBLE format. For more information, see the Microsoft Web site. If you are sourcing from an 8-channel file, it is recommended that the sampling rate and bits per sample of the source file and the encoded content match.

Six mono channel .wav files. To create the files, use an audio editing program to fold down your audio to six files, one for each channel. When you set up your source in the encoder, you specify which channel each file is associated with. Each .wav file cannot exceed 2 gigabytes (GB) in size. This option is not available with 7.1 audio.

An existing multichannel Windows Media Audio file. Use an existing file to encode the file at a different bit rate. It is not possible to encode an existing multichannel Windows Media Audio file if the encoder is on a computer running Windows 2000.

You must use either the Windows Media Audio 9 Professional codec or the Windows Media Audio 9 Lossless codec and an audio format that supports multichannel encoding when encoding multichannel content. In addition, the user playing your content must have Microsoft Windows XP and a player that is based on the Windows Media Format 9 Series Software Development Kit (SDK). Otherwise, the audio will be folded down automatically to two channels for stereo speakers.

The encoder automatically folds the channels down to two for playback with stereo speakers. If you are encoding 5.1 audio, you can control the fold-down distribution between the surround, center, and subwoofer channels on the Processing tab of the Properties panel. If you encoded the content to a file, you can also use Windows Media File Editor to control the fold-down distribution in the output file.

Sourcing from devices

When you source content from devices, you must first choose the audio or video devices you want to use. After choosing the devices, you can set their properties directly from the encoder. The properties for some devices, such as audio and video cards, are global and apply not only to all sources in your encoding session but to all programs on your computer. (For example, brightness, contrast, capture dimensions, and audio mixer settings.)

You can use devices and capture cards only once in a session. For example, if you create two sources-one source is a live event in which a speaker is introducing a new video, and the second source is the video-you need a separate card and device for each source.

Some devices can be controlled directly from the encoder. If you have enabled device control, you can set up an edit decision list (EDL) in which you identify the portions of tape that you want to encode.

You can configure audio and video device properties by using the New Session Wizard, the Properties panel, or the Configure Devices command on the Tools menu. Devices must already be installed on your computer to configure them in the encoder. You cannot use the encoder to add or remove hardware; use Control Panel instead.

If you have installed a supported TV tuner card, you can change the TV channels by using the encoder.

Enabling device control

By using the device control feature, you can run certain types of devices directly from the encoder. Device control enables you to control the play, pause, stop, fast-forward, rewind, and eject functions of your device from the encoder. To enable device control, the device must be connected to an IEEE 1394 digital video port, or you can use a video tape recorder (VTR) that supports the Sony RS422 protocol and that is connected through a COM port. You can also use the built-in edit decision list (EDL) of the device control feature to arrange and encode your clips in any order.

When you have enabled device control, you can use two-pass encoding if you have done the following:

Chosen to encode to a file

Chosen to store content temporarily

Set up an EDL for the content

Note

If a device you are using in the session does not appear in the Configure Devices dialog box, close the dialog box, click Apply, and then open the dialog box again.

Setting up an EDL

If you have enabled device control, you can specify, by time stamp, the exact place within your audio or video content that you want encoding to begin and end. To do so, you must create an edit decision list (EDL), which identifies the portions of tape you want to encode.

It is not recommended that you use an EDL for a broadcast because the encoder requires extra time to seek to the EDL points during encoding. During a broadcast, this could cause excessive buffering on a player.

You can add as many EDL entries as you want in any order-not necessarily in the order in which they occur in the tape. You can also set up an EDL that sources from multiple tapes. During the encoding session, the encoder will prompt you when it is time to change the tape.

You should use a prestriped tape when setting up an EDL. To prestripe a tape, you can record the tape continuously from beginning to end when you first buy the tape. This ensures that the time code in the tape is continuous. If the tape is not prestriped, then the device will generate a new time code every time you set up an EDL for the device.

Capturing screens

You can capture your entire desktop screen, individual windows, or a region of the screen and broadcast the screen or encode it to a file just as you would any other content. You can use the screen capture feature for:

Capturing from .avi files that were created with a third-party screen-capture utility.

Capturing a window (or the entire desktop) directly from your desktop.

Capturing from a card that is connected to a scan converter device.

When you capture a window, you can save the session for later use. Keep in mind, however, that the title of the window and its coordinates are saved along with all the other configuration information in the session file. When you reload the session file for a subsequent screen-capture session, the encoder looks for a window that matches the stored title. If the encoder does not find one, it captures a window that matches the stored coordinates.

When you capture the entire desktop and save the session, the display size and color settings for your monitor are saved in the session file. If, after saving the session, you decide to change the screen size or color, you must create a new session to include these settings.

If your screen saver is displayed while you are capturing a window or the entire desktop, the screen saver will be encoded. Therefore, it is recommended that you turn off your screen saver when capturing a window or the entire desktop.

Notes

Artifacts can be introduced when an analog signal is run through a scan converter and converted to National Television Standards Committee (NTSC) format. These artifacts are amplified during encoding and can degrade the quality of the encoded video.

When you are done capturing a screen, be sure to click Stop encoding on the toolbar. Simply minimizing the window being captured does not end the encoding session.

Improving performance when encoding screens

Because of the amount of data being manipulated and the CPU power required, capturing screens is a performance-intensive process. Use the following guidelines to ensure that the screen image you capture will encode and play well:

Use a fast processor.

Use the Windows Media Video 9 Screen codec.

Set your monitor to use a lower display size. For example, capturing at a 1024 × 768 resolution yields more data than capturing at 640 × 480.

Set your color display to 16-bit or 8-bit color. Or, to further improve the CPU usage set the encoder to run in 256-color mode. Keep in mind that running in 256 colors can introduce a palette change when switching between programs that have different color schemes. The encoder does not support palette changes for real-time screen capture. Therefore, you should use 16-bit colors or capture to an .avi file first, then use the encoder to convert the file to Windows Media Format.

Use a low frame rate. You may have to experiment with the setting to determine the frame rate that meets your needs.

Capture a smaller image.

Use a higher bit rate.

Avoid multiple scene changes, such as opening and closing windows in rapid succession during the capture.

Capture screens or regions only from the primary monitor when using a dual-monitor scenario.

Disable hardware acceleration. (However, enable hardware acceleration after completing the screen capture for best results with other programs.)

Quit all video programs you are not using.

Set up the output frame size to be the same as the source. Do not use the encoder to resize the source video.

Inserting script commands

You can insert script commands into a stream while you are encoding. The encoder supports the following types of script commands:

Captions. Free-form text strings that are displayed in a player along with your encoded content. For the captions to be visible, users must have enabled captions in their player.

Closed captioning. If your capture card supports capturing closed captioning data, you can encode the closed captioning.

URLs. When inserted into a stream, the user's default browser opens and the requested URL loads into the browser. If you have embedded the player within a browser, the requested URL replaces the player, and users cannot view the rest of the stream. You can get around this either by displaying the requested URL in a separate frame in the same browser instance or by opening an additional instance of the browser.

Custom script commands. In addition to supporting captions and URLs, a player automatically processes FILENAME, EVENT, and OPENEVENT script commands. You can use the FILENAME command to open a specific digital media file at the time you specify. You can use the EVENT command to create custom script commands. For example, you can insert an advertisement into the stream. Note that the code for the specified event must be defined in the Windows Media metafile for the stream for the player to perform the specified event. The OPENEVENT command precedes the actual EVENT command. The OPENEVENT command allows the player to prebuffer the content so that when the specified event occurs, the switch between streams appears to be seamless.

For detailed information about the script commands supported by Windows Media Player 9 Series, see the Windows Media Player 9 Series Software Development Kit (SDK). For information about the script commands supported by Windows Media Services 9 Series, see the Windows Media Services 9 Series SDK.

Because script commands are saved in the stream, they are not available for editing.

Inserting script commands into an encoding session requires that you select scripts as a source type when setting up your session. You cannot include scripts when you set up a session using the New Session Wizard, but you can add scripts to the session through the Sources tab of the Properties panel.

Using multiple sources in a session

You can use multiple sources in a session. Although only one source streams at a time, as you encode, you can switch between sources to stream different content. For example, before broadcasting a company meeting, you can set up sources for the main content as well as for welcome, intermission, and goodbye content. When you broadcast the event, you can start with the welcome source, switch to the main speaker when appropriate, switch to the intermission source during a break, and then switch to the goodbye source when the event finishes.

If you are using the Windows Media Audio 9 Voice codec in a multisource session, the mode (voice-only or mixed voice and music) of the first source determines the mode of the subsequent sources. For example, if you choose the voice-only or mixed mode for the first source, subsequent sources will be encoded in the same mode. However, if you specify the mixed mode for the first source and set up an optimization definition file for that source, subsequent sources in the session will be encoded in the voice-only mode.

Customizing a session

This section provides information about options you have for customizing an encoding session to meet your needs. If you customize a session and want to reuse it frequently, you can save the session to a session file and then add it to the list of quick starts.

Cropping and resizing video before encoding

Using Windows Media Encoder, you can crop the edges of your input video image. For example, noise often occurs at the edges of an image, so you can crop one or more edges to eliminate the affected rows. You can specify how much to crop from each side of an image, or you can use default values for cropping. After cropping, you can resize the height and width of the output video. By default, the output video image is stretched to match the frame size specified in the profile. However, you can resize the video so that the output image matches the dimensions of the cropped image. Or, you can have the video resize automatically to make use of the bandwidth specified in the profile. You can also specify custom resize dimensions.

MBR video and multiple sources

If you are encoding MBR video, you can resize the output frame size for each bit rate separately. This means that an MBR file or stream can contain video images of varying sizes.

If you have multiple sources in a session, the output dimensions of the first source determine those of the subsequent sources. Therefore, it is only possible to resize the first source in a multisource session.

Detecting the input size

When you source from a file, the encoder can detect the size of the source video before encoding begins; when you source from devices or screen captures, the input size cannot be detected before encoding. For this reason, when sourcing from devices or screen captures, you should specify the input size when you crop and resize video. When you do so, the encoder will detect the actual input size when encoding begins. If the actual input size is different than the size you specified, the percentage of cropping you specified (rather than the actual pixel values) will be applied to the actual input size.

For example, assume you indicated that the input size was 100 x 200 pixels, and specified the following crop values:

Top: 4 (2 percent of height)

Bottom: 4 (2 percent of height)

Left: 10 (10 percent of width)

Right: 10 (10 percent of width )

If the encoder detected that the actual input size is 200 x 400, the actual crop values would match the percentage of cropping, as follows:

Top: 8 (2 percent of height)

Bottom: 8 (2 percent of height)

Left: 20 (10 percent of width)

Right: 20 (10 percent of width )

Hardware cropping

If your capture card supports hardware cropping, it is recommended that you use the hardware to crop the video. Refer to the documentation for your capture card for information about hardware cropping.

If your capture card does not support hardware cropping, or if you are sourcing from a file, the cropped video will not be displayed in the Input area on the Video panel until you start encoding.

Resizing

For best results, do not resize your output video. Resizing can result in suboptimal output. However, if you are encoding to a file by using the Windows Media Video 9 codec, and the time required to encode is not important, you can improve the quality of resized content by adjusting the encoder performance setting for the Encode to file option to better quality. Note that the encoding time increases significantly if you use this method.

Caution

You should not resize the image when you are encoding a screen, which can result in poor quality in the encoded content.

Preserving the pixel aspect ratio of video

If your video source has nonsquare pixels, you can preserve its pixel aspect ratio. Check the documentation for your video device to determine whether it uses nonsquare pixels.

The pixel aspect ratio is the width (x) of the pixel with respect to its height (y). A square pixel has a ratio of 1:1, but a nonsquare (rectangular) pixel does not have the same height and width. This concept is similar to the frame aspect ratio, which is the total width of an image with respect to its height. However, these aspect ratios are not necessarily tied together. For example, a widescreen image with a frame aspect ratio of 16:9 can be made of square or nonsquare pixels.

If you encode a video source with nonsquare pixels as though the pixels are square, the output will distort, as shown in the following diagram.

If you know the frame aspect ratio (Ix:Iy) and exact height and width of your image source, you can use the following formula to determine the x and y values of the pixel aspect ratio.

PixelAspectRatioX / PixelAspectRatioY = (Ix * height) / (Iy * width)

For example, if your image is 720 by 360 pixels, and the frame aspect ratio is widescreen (16:9), then PixelAspectRatioX=8 and PixelAspectRatioY=9:

PixelAspectRatioX / PixelAspectRatioY = (16*360) / (9*720) = 8/9

Notes

If you set the size of the output video to be the same as the source video, and the source video has nonsquare pixels, then the pixel aspect ratio of your source video is automatically preserved in the output video.

Preserving the pixel aspect ratio of video increases the file size or stream bit rate.

Optimizing video and audio

You can use Windows Media Encoder to deinterlace source video that is interlaced, apply an inverse telecine filter to content that is telecined, or maintain the interlacing in your source video.

If you are not sure whether your source content is interlaced or telecined, you can use the encoder to detect the format by clicking Detect on the Processing tab of the Properties panel.

If your audio content is primarily voice, combined with some music, you can use the Windows Media Audio 9 Voice codec and optimize the content for voice.

Deinterlacing or maintaining the interlacing in video

A video frame can be either interlaced or progressive. An interlaced video frame contains two fields per frame captured at different time instants. When the video is being rendered, the lines of one field are displayed first, and then the lines of the second field are displayed. In contrast, with a progressive video frame, the lines in each frame are painted sequentially. Interlaced content is common because the NTSC and PAL standards use interlaced video signals.

Deinterlacing video

When interlaced video is played on a progressive-scan display, such as a computer, it can appear to flicker as the fields are rendered. Deinterlacing is the process of creating a progressive frame of video out of an interlaced frame, which reduces the flickering. The encoder has three deinterlace filters. The filter used by the encoder depends on the difference between the input and output frame size and frame rate.

Normal deinterlacing. This is the default filter used when you select the deinterlace option. This filter blends the even and odd fields of an interlaced frame to create a progressive frame, as shown in the following diagram.

Half-size deinterlacing. This filter is used when the number of lines specified for the output video is half (or less) than those of the input video. For example, this filter is used when the resolution of the input video frames is 640×480 pixels and the output resolution is 320×240 pixels. This filter uses an algorithm that blends the fields, rather than simply removing one field of data. This results in higher-quality output video.

Half-size, double frame rate deinterlacing. This filter is used when the number of lines specified for the output video is half (or less) than those of the input video and the output frame rate is twice as high as the input frame rate. This filter produces a frame from each field of the video sequence, as shown in the following diagram.

The benefits of this filter are that it produces high-quality progressive frames because there is no need to blend information across fields. In addition, the full motion of the interlaced fields is maintained. However, this filter has higher performance and bit rate requirements.

Deinterlacing is not supported for a source that was not previously interlaced.

Maintaining interlacing in source video

Maintaining the interlacing in your video is useful if it will be displayed on interlaced playback devices, such as televisions. You must use the Windows Media Video 9 codec to be able to use this option. In addition, the user playing your content must have Microsoft Windows XP, a player that is based on the Windows Media Format 9 Series Software Development Kit (SDK), and a graphic card that supports interlacing; otherwise, your content is automatically deinterlaced.

If your source video is mixed (progressive and interlaced) and you select the Maintain interlacing option, the output video will also be mixed.

Notes

Some capture cards support hardware deinterlacing. It is recommended that you use hardware deinterlacing if possible.

Maintaining interlacing in source video when encoding at a low frame rate (for example, 15 fps) can introduce undesirable artifacts in the encoded content. Therefore, if you are encoding at a low frame rate, it is recommended that you deinterlace the video, even if the content is intended for display on an interlaced playback device.

Applying the inverse telecine filter to video

The inverse telecine process removes frames that were added during telecining when film (24 fps) was converted to NTSC video (29.97 or 30 fps). The inverse telecine filter removes artifacts and improves the quality of encoded content, especially at low bit rates.

Content is telecined in a pattern called 3:2 pulldown, which refers to the process used to create the extra frames. If the 3:2 pulldown pattern is consistent throughout the source video, the video is said to be coherent. However, video often is not coherent, meaning that there are breaks in the 3:2 pulldown pattern. For example, pattern breaks, or incoherencies, can be introduced when video is edited. If your content is coherent, you can choose the exact frame at which the 3:2 pulldown pattern starts. Or, you can choose to have the pattern be detected automatically.

Inverse telecine is not supported for:

An NTSC source that was not previously telecined.

Content that has time compression applied.

Content for which you are preserving or creating a time code.

Optimizing audio for voice

If you are sourcing from audio that is entirely or primarily voice, you should use the Windows Media Audio 9 Voice codec, which is designed to encode voice. You can optimize the codec behavior by identifying if the content is voice only or if it also contains some music. If the audio is a mixture of voice and music, during encoding the codec automatically uses the appropriate algorithm to optimize encoding for the content (voice or music). Or, you can create an optimization definition file, which is a text file that identifies the places in your file where music starts and ends. The unspecified portions in the file are treated as voice.

If you are using the Windows Media Audio 9 Voice codec in a multisource session, see Using multiple sources in a session for information about codec behavior.

Specifying a language for content

When you encode content, a language is automatically associated with your content. If you want, you can encode content in different languages. You can then use Windows Media Stream Editor to add content of different languages into one file. Then, users can choose the language they want to listen to when playing the file.

Applying time compression to your content

By applying time compression to your content while it is encoding, you can speed up or slow down the content during playback. Speeding up the content reduces the amount of time required to view the entire video or listen to the entire audio file, which is useful when you have to fit content into a specific time slot. Slowing down the content can improve comprehension in situations where the material is highly technical or the language is not native to users. Using time compression has the following requirements:

Your source must include audio content.

Every source in the session must be a file.

You must encode to a file. (Time compression is not supported for broadcasts.)

You must be using a one-pass encoding mode (either one-pass CBR or quality-based VBR).

You cannot apply the inverse telecine filter in conjunction with time compression.

You cannot use the looping feature in conjunction with time compression.

You cannot apply time compression when sourcing from multichannel audio.

If you are sourcing audio and video from separate files, encoding will stop when the end of the file with the shorter duration is reached.

Windows Media Encoder has two time compression features that you can use independently of one another or in tandem:

Accelerating or decelerating the audio and video frames. Accelerating and decelerating have no effect on the pitch of the audio stream.

Detecting and removing pauses in voice or action. Periods of silence are removed from the audio, and frames are removed from the video. If you elect to create a log file, the start and end times of the segments that are removed are listed in the log file so you have a permanent record.

Before using time compression, be sure you start with audio that is the best quality possible. Artifacts or noise in the source content will be more pronounced when the content is accelerated. Noise in the source content also decreases the accuracy of pause removal.

Always test your content to ensure that you achieve the desired results. To run a test, encode some content by using time compression and then play it. If the results are unsatisfactory, adjust the time compression settings, and then encode the content again.

Using CBR encoding

With CBR encoding, you specify the bit rate that you want to maintain and then set the size of the buffer. The bit rate will fluctuate across the stream; however, the fluctuations are constrained by the buffer size. The content quality also fluctuates to ensure that the buffer does not overflow or underflow. (If you want to guarantee the quality of the encoded output, use quality-based VBR encoding.) The size of the buffer determines the amount of initial delay when the content is played, but using CBR encoding ensures that the content is streamed smoothly, assuming that the bit rate is compatible with the client connection speed. If possible, use two-pass CBR encoding to reach a higher quality without losing the advantages of CBR encoding. Two-pass encoding is not supported in all scenarios.

Using VBR encoding

Windows Media Encoder supports three VBR encoding modes:

Quality-based VBR. With quality-based VBR encoding, you specify a desired quality level (from 0 to 100). Then, during encoding, the bit rate fluctuates according to the complexity of the stream-a higher bit rate is used for intense detail or high motion, and a lower bit rate is used for simpler content. The advantage of quality-based VBR encoding is that quality remains consistent across all streams for which you specify the same quality setting. The disadvantage is that you cannot predict the file size or bandwidth requirements of the encoded content before encoding. Quality-based VBR encoding uses one-pass encoding. This mode is good for archiving content.

If you are encoding audio content with this encoding mode, you have the option of using the Windows Media Audio 9 Lossless codec. Lossless encoding produces superior quality results, while also providing some compression of the data.

Bit rate-based VBR. With bit rate-based VBR encoding, you specify the desired average bit rate. At any point, the bit rate may exceed the average bit rate but the overall bit rate does not exceed the average bit rate. Bit rate-based VBR encoding uses two-pass encoding. In the first pass, the data complexities are analyzed. Then, in the second pass, the quality level is set to achieve the average bit rate. The advantage of bit rate-based VBR encoding is that the compressed stream will achieve the highest possible quality level while staying within a predictable average bandwidth.

Peak bit rate-based VBR. Peak bit rate-based VBR encoding is similar to the bit rate-based mode, except that you also specify the peak bit rate. The encoder determines the image quality that can be achieved without exceeding the peak bit rate. The bit rate does fluctuate during encoding, but does not exceed the specified peak bit rate. Use this option when you plan to distribute the content for playback on a device that has a constrained reading speed, such as a CD or DVD player. Peak bit rate-based VBR encoding uses two-pass encoding.

Notes

Only certain codecs support VBR encoding.

The quality-based and bit rate-based VBR encoding modes are not recommended for use in a streaming scenario as a result of the high bit rate peaks in the content. In a streaming scenario, when all players reach the point in the stream with a high bit rate at approximately the same time, there is a large peak in demand. This peak may exceed the network capacity, resulting in a negative playback experience.

Setting up an MBR stream

If you plan to deliver your content as a unicast stream from a server running Microsoft Windows Media Services, encoding multiple-bit-rate (MBR) stream provides users with better quality content during times of network congestion. When you set up an MBR stream, your content is encoded at each bit rate that you specify. When a player receives an MBR stream, only the stream that is the most appropriate for current network conditions plays. The Windows Media server and player handle the process of selecting the appropriate stream, which is invisible to the user. Because an MBR stream is intended for use only in a streaming scenario, you can only use CBR encoding when encoding an MBR stream.

You can encode an MBR stream for both audio and video content; however, it is not necessary to use MBR encoding for both audio and video in a stream. For example, you can stream audio at one bit rate and have multiple bit rates for the video portion of the stream.

When setting up an MBR stream, keep in mind that the more bit rates you select, the larger the aggregate bandwidth for live stream distribution from the encoder to a Windows Media server is required. To estimate the aggregate bandwidth of an MBR profile, calculate the sum of each audio and video bit rate, and the script bit rate. Also keep in mind that encoding an MBR stream uses more processing power for the encoding computer.

If you are using the Windows Media Audio 9 Voice codec in an MBR session and you specify the mixed voice and music mode, it is recommended that you do not include any bit rates below 8 kilobits per second (Kbps) in the session. The reason for this is that any bit rates below 8 Kbps will be encoded in voice-only mode, which may result in suboptimal quality in your audio content.

Using digital rights management to protect content

You can control the use of your encoded content by protecting it with digital rights management (DRM) technology while you are encoding. You can use DRM either when encoding to a file or when broadcasting the stream. Content is encoded, encrypted with a key, and then a license is required by users to play the content. This license contains the key to unlock the content and the rights that govern its use. For example, the license determines the number of times a user can play the content or when the license expires.

Important

Licenses are issued by a third-party license provider, so you must set up an account with one before you can protect your content.

Steps involved in using DRM

The basic steps in using DRM are as follows:

Set up an encoding session.

Set up an account with a license provider (if you haven't already done so) and create a DRM profile.

In the session, identify the DRM profile to use with the content.

Encode and distribute your content, either by streaming it or providing files for download.

When users play the protected content, the player acquires a license, which is issued by the license provider you chose. The user can then play the content according to the rights that are included in the license.

For users to play protected content, they must use a player that supports Microsoft DRM technology. For a list of players, see the Microsoft Web site.

Reusing DRM profiles

After you have created a DRM profile, you can reuse it in future sessions. You can also export the profile so that you can import it for use on a different encoding computer. Similarly, you can import a DRM profile from another computer. To ensure security, DRM profiles are maintained on a per-user basis. This prevents others from viewing, editing, and using DRM profiles that you create. DRM profiles have a .drm file name extension.

Embedding a watermark in content

You can embed a digital watermark into a stream. Watermarks are a way of adding information, such as a copyright or artist's name, to the audio and video stream, but watermarks are not audible or visible to the user. The watermark is preserved in the encoded file or stream and cannot be removed. The watermark can be used to identify content even if it is copied or edited.

You must obtain and register a third-party plug-in to work with watermarks. For information about obtaining a watermark plug-in, see the Microsoft Web site.

Using hardware profiles

Windows Media-based content is no longer played back solely on computers. Instead, there is increasing demand for playing the content on various hardware devices, such as set-top boxes, wireless handsets, and DVD players. If you want to ensure that your content can be played on a certain type of hardware device, you can encode your content by using a hardware profile. Windows Media Encoder includes a number of hardware profiles, which are intended to meet a range of encoding needs.

Even if you do not use a hardware profile to encode content, you can still determine the type of hardware device that can play the content. All encoded content is mapped to a hardware profile; the profile used to encode is indicated in the Encoding Results dialog box (in Profile conformance) that appears when encoding is complete.

Video profiles

Windows Media Encoder includes the following hardware profiles: simple low, simple medium main low, main medium, and main high. For more information about each profile, see Hardware profiles for video. A given profile and level always supports lower profiles and levels. For example, a device that supports the main profile, medium level, also supports the main profile, low level, and all levels in the simple profile.

Audio profiles

The following table lists, in ascending order, the hardware profiles for audio content included with the encoder.

Audio profile	Description
L1	For audio bit rates from 64 Kbps to 128 Kbps (uses the Windows Media Audio 9 codec)
L2	For audio bit rates that are less than or equal to 160 Kbps (uses the Windows Media Audio 9 codec)
L3	For audio bit rates less than or equal to 384 Kbps (uses the Windows Media Audio 9 codec)
L	Supports all bit rates; intended for playback on computers as a demonstration of codec capabilities (uses the Windows Media Audio 9 codec)
S1	For audio bit rates that are less than or equal to 20 Kbps, for low-complexity voice content (uses the Windows Media Audio 9 Voice codec)

It is not possible to select the profiles listed in the following table when setting up a session. However, if the encoded audio meets the parameters listed in the table, the content will be mapped to the corresponding hardware profile.

Audio profile	Description
S2	For audio bit rates that are less than or equal to 20 Kbps, for mixed music and voice content (uses the Windows Media Audio 9 Voice codec)
M1	For audio bit rates that are less than or equal to 384 Kbps, sampling rate less than or equal to 48 KHz, and 5.1 or fewer channels; recommended for surround sound for standard-definition movies (uses the Windows Media Audio 9 Professional codec)
M2	For audio bit rates that are less than or equal to 768 Kbps, sampling rate less than or equal to 96 KHz, and 5.1 or fewer channels; recommended for surround sound for high-definition movies (uses the Windows Media Audio 9 Professional codec)
M	Supports all bit rates, sampling rates, and channels; intended for playback on computers as demonstration of codec capabilities (uses the Windows Media Audio 9 Professional codec)

Combining video and audio profiles

The following table lists recommended combinations of video and audio hardware profiles.

Video	Audio
Simple low	L2 or S2
Simple medium	L2 or S2
Main low	L2 or S2
Main medium	L3, S2, or M1
Main high	L3, S2, or M2

Hardware profiles for video

This topic provides detailed information about the hardware profiles available for video content that are installed with Windows Media Encoder.

Simple low (SP@LL)

Item	Value
Target hardware devices	Wireless handsets
Maximum resolution	176 × 144
Maximum frame rate	15 fps
Maximum bit rate	96 Kbps
Maximum buffer size	About 3.4 seconds at maximum bit rate

Simple medium (SP@ML)

Item	Value
Target hardware devices	Handheld computers, personal data assistants, and high-end wireless handsets
Maximum resolution	352 × 288
Maximum frame rate	15 fps at 352 × 288 24 fps at 320 × 240
Maximum bit rate	384 Kbps
Maximum buffer size	About 3.3 seconds at maximum bit rate

Main low (MP@LL)

Item	Value
Target hardware devices	Low-end set-top boxes
Maximum resolution	352 × 288
Maximum frame rate	30 fps
Maximum bit rate	2 Mbps
Maximum buffer size	About 2.5 seconds at maximum bit rate

Main medium (MP@ML)

Item	Value
Target hardware devices	High-end set-top boxes; DVD players; and DirectX Video Acceleration (VA)-enabled graphic cards
Maximum resolution	720 × 576
Maximum frame rate	30 fps at 720 × 576 (NTSC) 25 fps at 720 × 576 (PAL)
Maximum bit rate	10 Mbps
Maximum buffer size	About 1 second at maximum bit rate

Main high (MP@HL)

Item	Value
Target hardware devices	DVD players; DirectX VA-enabled graphic cards; and digital cinema
Maximum resolution	1920 × 1080
Maximum frame rate	30 fps at 1920 × 1080 60 fps at 1280 × 720
Maximum bit rate	20 Mbps
Maximum buffer size	About 2 seconds at maximum bit rate

Using transform plug-ins

Windows Media Encoder has a customizable user interface that enables developers to write transform plug-ins that customize and build upon encoding functionality. The encoder supports Microsoft DirectShow® and DirectX® Media Object DMO transform filters. You can configure plug-ins on a per-source basis.

For information about DirectShow, see the Microsoft Web site. For information about DirectX Media Object, see the Microsoft Web site.

Output options

You can either encode content to a file for later use, or you can broadcast the content live. If you are broadcasting, you can either push the stream to a server running Windows Media Services or you can enable Windows Media servers and players to pull the stream directly from the encoder. You can archive a copy of the broadcast to a file. Before or after encoding, you can:

Change the output port for a broadcast.

Select or cancel archiving to a file.

Change the name or location of the output file.

While encoding, you can:

Select or cancel archiving to a file.

Change the name of the archive file if you are not currently archiving.

While encoding, you cannot:

Change the port number.

Change from a broadcast session to an encode-to-file session.

Encoding or archiving a broadcast to a file

You can encode content to a file, and you can archive a live event to a file for later use.

Archiving on a Windows Media server versus archiving on the encoding computer

If you are broadcasting through a Windows Media server, you can archive the broadcast on the server rather than on the encoding computer. Archiving on the Windows Media server is the best solution when:

You want the archive to be available immediately for viewing.

The resources on your encoding computer are mostly being used for encoding.

You have more disk space available on your server than on your encoding computer.

If you choose to archive the broadcast on the encoding computer, all the sources you set up in the broadcast session are archived automatically. However, archiving all sources is not always desirable. For example, if one of the sources is an advertisement, you may not want to archive the advertisement. You can have the encoder automatically pause archiving for sources that you specify.

Enabling seeking in the output file

Indexing at each key frame is turned on by default whenever you archive or encode to a file and your source includes video. By indexing the content, users can make use of the fast-forward and rewind features of a player while viewing encoded content. Indexing is not available for broadcasts. You can also choose to enable frame-level seeking in an output file by generating a time code (or preserving the time code already present in the source video). You can generate a time code when your source includes video and you are sourcing from digital video (DV) files in Audio-Video Interleaved (AVI) format, capture devices, and digital devices. You can preserve a time code when your source includes video and you are sourcing from digital video (DV) files in Audio-Video Interleaved (AVI) format or digital devices. To preserve the time code for a VTR, you must set up an EDL for the session. You cannot preserve or create a time code when you are applying the inverse telecine filter.

Storing content temporarily

If you are encoding to a file while sourcing from devices, the encoding process might fall behind the capturing process, which reduces the quality of the encoded content. To prevent this from occurring, you can temporarily store the captured content and then encode it to a file. If you choose this option, capturing and encoding occur simultaneously and data is only stored temporarily if encoding falls behind. For the best quality, especially when capturing a large amount of data, you can choose to capture first and then encode only after you have stopped capturing. (This option is not available when you are sourcing from a digital device. In addition, it is not possible to capture first, and then encode in conjunction with limiting the size or duration of the output file.)

If you enable this feature (including the option to capture first, and then encode) in a multisource session, you should wait until all data has been received from the first source before you stop encoding. For example, assume you have two sources, and only want to capture part of the second source. You can switch to the second source during encoding, but you should wait until the video preview/postview (on the Video panel) or the Input area (General tab of the Monitor panel) indicate that the first source has finished sending all data before you stop encoding. This ensures that you will capture all of the content you want.

About the .asf, .wma, and .wmv file name extensions

The .asf, .wma, and .wmv file name extensions represent the standard Windows Media file format. The .asf file name extension is normally used with Windows Media-based content created by using Windows Media Tools 4.0. The .wma and .wmv file name extensions were introduced as standard naming conventions with Windows Media Encoder 7 to enable users to easily differentiate between audio-only (.wma) files and video (.wmv) files. However, the three extensions can be used interchangeably. Some tools and services that were created for use with earlier versions of Windows Media Technologies require the .asf extension to accept the content. You can simply rename any .wma or .wmv file with the .asf extension to use them with those tools. (However, it is recommended that you use the most current tool or service, when possible.)

Encoding uncompressed audio and video files

Using Windows Media Encoder, you can capture and archive high-quality content to an archive file for later use. For most situations, the File Archive option, which uses quality-based VBR encoding, is most appropriate. However, if you plan to edit the content at a later date, you may want to consider encoding uncompressed files.

Storage requirements for uncompressed files are significantly higher than for other files to which compression has been applied. It is recommended that you store the content on an NTFS volume. The FAT32 file system has a file size limit of 4 GB. If you expect your content to exceed 4 GB, you should reconfigure your hard disk to use NTFS.

When you capture uncompressed content from a device, such as a camera or VCR, the resulting video is created in the YUV format YV12, regardless of the pixel format specified on the device or in the profile. The Windows Media Video 9 codec is optimized for YUV, making it the preferred format for quality, size, and performance. The resulting audio is created in the pulse code modulation (PCM) format.

For best results when capturing uncompressed content:

Use a fast hard disk that can accommodate encoding at high bit rates.

Use 15 fps when capturing 640 x 480 resolution.

Use 30 fps when capturing 320 x 240 resolution.

Broadcasting content live

When you want to broadcast your content live, you can choose to either push the stream from the encoder to a Windows Media server or you can enable clients (Windows Media servers or players) to pull the content. The method you use depends upon your situation.

Push scenarios

Pushing a stream from the encoder is useful if the encoder is behind a firewall or if you want to initiate the connection from the encoder. For example, assume you have just received last-minute notice that the president of your company wants to stream a talk to the company employees. The Windows Media server is located remotely, outside your company firewall. In fact, it is the middle of the night for the server administrator. By pushing the stream from the encoder, you can get the stream past the firewall, meet the president's request, and avoid making an emergency call to bring someone in to administer the server. Push distribution is only available with Windows Media Services 9 Series in Windows Server 2003.

Pull scenarios

Enabling Windows Media servers to pull a stream is useful in several scenarios. First, if there are multiple distribution servers, all connecting at different times, each server can initiate the connection with the encoder when the server is ready to stream. Next, pulling from a server is useful if it is important to minimize bandwidth usage between the server and the encoder. For example, the server administrator can add a publishing point and configure it to start automatically upon client request, which means that the server does not initiate the connection with the encoder until the first client connects. This eliminates unnecessary bandwidth use between the server and the encoder. (This scenario is only available with Windows Media Services 9 Series in Windows Server 2003.) Finally, pulling from the server is also useful when the server is behind a firewall. For example, assume you have set up the encoder on a public network because you are streaming events at a conference. You need to get the stream to a distribution server in the protected network. The server administrator can pull the stream through the firewall.

Enabling players to pull the stream is useful when you do not expect to have many clients viewing the stream. Windows Media Encoder allows up to five clients to connect directly to it during a broadcast. When you are enabling clients to pull the stream, you can restrict access to the content by IP address or by groups of IP addresses.

Pushing a stream from the encoder

When pushing a stream from the encoder, you must specify the Windows Media server to which you want to stream and the broadcast publishing point (either new or existing) you want to stream through. On the Windows Media server, you have a number of options for configuring a publishing point, including setting limits on the number of players that can view the stream, controlling access to content, and setting up logging. If you have a configuration that you want to use repeatedly, you can add a broadcast publishing point on the server, configure it to meet your needs, and then copy the settings from that publishing point each time you push a stream to the server. For more information about configuring broadcast publishing points, see Windows Media Services Help. Push distribution is only available with Windows Media Services 9 Series in Windows Server 2003.

Content can be delivered from a Windows Media server either as a multicast or a unicast stream.

Announcement required for a multicast stream

If you are planning to deliver content as a multicast stream from the server, you must create and distribute an announcement before you begin encoding. An announcement is the means by which you communicate that your content is available to players. You can use the Multicast Announcement Wizard in the encoder to create the announcement. Or, alternatively, you can create the announcement on the server. Creating the announcement on the encoder requires that you have access permission to the Windows Media Services service through the distributed version of Component Object Model (DCOM). If you make any changes to the session configuration after you have created the announcement, you must create another announcement before you begin encoding.

Accessing the Windows Media server

To push a stream to a Windows Media server, the WMS HTTP Server Control Protocol plug-in must be enabled on the server. In addition, you must have write access permissions on the server through the WMS Publishing Points ACL Authorization plug-in. You must also have create access permissions for the plug-in if you want to add the publishing point from the encoder rather than from the server. The permissions must be set at both at the server level and at the publishing point level. To configure the plug-in, you must have access to the Windows Media Services service through DCOM.

Local administrators on the server automatically have both write and create access permissions on the server.

When you begin encoding, the encoder initiates the connection with the server.

You can use the New Session Wizard or the broadcast quick start to push to a Windows Media server, or you can set up a push session on the Properties panel.

For more information about setting up a multicast or unicast stream from a Windows Media server, see Windows Media Services Help.

Creating an announcement

You can use the Multicast Announcement Wizard in the encoder to create the announcement, or you can create it on the Windows Media server. Creating the announcement on the encoder requires that you have access permission to the Windows Media Services service through DCOM. If you make any changes to the session configuration after you create the announcement, you must create another announcement before you begin encoding.

When you run the wizard on the encoder, you create the announcement file, multicast information file, and a Web page that contains an embedded player and a link to the announcement. You are asked to provide a name for the files and to save the files to a storage location that is accessible to players (or to a temporary location, if you plan to broadcast later.) The storage location can be either on your Web server for HTTP access or on a public share if you are providing access using a Universal Naming Convention (UNC) path. If you make the files available from your Web server, be sure to configure the Web server to either not allow caching of the file or to require a refresh check when cached by a client to prevent players from using multicast information that is outdated.

Distributing the announcement file

You have several options for making the multicast stream available to users. You can place a link to the announcement file on a Web page, make the announcement available on a shared folder, or send the announcement in an e-mail message. Users can access the announcement either by clicking the link to the announcement on a Web page or by opening the announcement directly. When a user opens the announcement file (.asx) in the player, the player extracts an URL in the announcement file; the URL points to the multicast information file. The player then downloads the multicast information file with the URL and begins playing the content.

Enabling clients to pull a stream from the encoder

To enable clients to pull the stream from the encoder, you simply set up a session and begin broadcasting directly from the encoder. Clients (Windows Media servers or players) can connect to the stream at any time by using the following URL format: https://IP_address:port (for Internet connections) or https://encoding_computer_name:port (for LAN connections). The encoder supports up to five direct connections during a broadcast by default. You can increase this number to 50 by editing a key in the registry. (Editing the key requires administrative credentials on the encoding computer.)

Stream format required for a multicast transmission

If you plan to deliver content as a multicast stream from a Windows Media server, the server must be able to detect the stream format from the encoder. A stream format contains information used by players to decode a multicast stream, such as the codecs, bit rates, and frame sizes; the format is stored in the header of the stream. If you start encoding before the server initiates the connection with the encoder, the server automatically detects the stream format. However, if you do not want to start encoding first, you can create a stream format file and make it available to the server administrator. The administrator can add the file to the list of supported stream formats on the server publishing point. Stream format files have an .asf extension.

Caution

Incorrectly editing the registry can severely damage your system. Before making changes to the registry, you should back up any valued data on the computer.

Note

This topic focuses only on the steps you must perform with the encoder when a Windows Media server is initiating the stream. For detailed information about the steps that must be performed on the Windows Media server, see Windows Media Services Help.

Restricting access to a broadcast

When you are enabling clients to pull a stream from the encoder, you can allow or deny access to the broadcast based on a static IP address or groups of IP addresses. By default, no clients are restricted from connecting to the broadcast. If you want to specify the clients that can connect, you can add the IP addresses to the allow list. Doing so prevents any unlisted clients from connecting. Or, if you want to prevent a specific client from accessing the broadcast, you can add that client's IP address to the deny list

If you make changes to the IP address list while encoding, your changes take effect only for clients that connect after you apply your changes. For example, if you add an IP address to the deny list while that client is connected, the client is not disconnected. However, if the client disconnects and then attempts to reconnect to the same broadcast, it is denied. If it is critical to disconnect a client immediately, you can stop encoding.

The following table provides an example of the order in which IP addresses are allowed or denied, depending on the restrictions that you set up.

Allow list	Deny list	Result
Empty	Empty	Allow all IP addresses
Empty	IP address 1	Deny IP address 1, allow all others
IP address 1	Empty	Allow IP address 1, deny all others
IP address 1	IP address 2	Allow IP address 1, deny all others
IP address 1	IP address 1	Deny all IP addresses
IP address 1, IP address 2	IP address 1	Allow IP address 2, deny all others

When you restrict access to a broadcast by IP address, you can specify both Internet Protocol version 6 (IPv6) and Internet Protocol version 4 (IPv4) addresses. IPv6 is the latest version of the Internet Protocol and was designed to accommodate the rapidly increasing demand for unique IP addresses. IPv6 increases the IP address size from 32 bits to 128 bits to support more levels of addressing hierarchy and a greater number of addressable nodes. For more information about IPv6, see the IPv6 page at the Microsoft Web site.

Note

You can track which IP addresses are connecting to your broadcasts by enabling logging to a file on the Event log tab of the Monitor panel.

Testing your content

It is always a good idea to test your content before providing it to users. To run a test, configure a session, and then encode some content. While the content is encoding, use the URL specified on the Connections tab of the Monitor panel to connect the player to the encoder and view the stream. Or, if you are encoding to a file, stop the encoder and then play the output file.

If you are planning to distribute your content by using a Windows Media server, you can conduct an end-to-end test. To do so, set up your Windows Media server to connect to the encoder by using the URL specified on the Connections tab of the Monitor panel.

As you view the stream, verify the following:

You are getting the expected frame rate.

Your bandwidth throughput is acceptable.

You are receiving an audio and video feed and the quality of each is acceptable.

For more information about streaming from a Windows Media server, see Windows Media Services Help.

System configuration options

This section provides information about options you have for configuring your encoding system, including information about how you can secure the encoding computer and protect the content you are encoding, the steps you can take to achieve optimal system performance, how to run multiple instances of the encoder on a computer, and batch encoding.

Security and Windows Media Encoder

Security considerations for Windows Media Encoder involve both security for the encoding computer and protecting the content you are encoding. To learn more about security issues relating to the encoding computer, refer to the security section of the operating system documentation.

To protect your content, you can protect it with digital rights management (DRM) during encoding.

If you are broadcasting, you can restrict access to the encoder by IP address. In addition, you can use Internet Protocol Security (IPSec), an industry-defined set of standards that verifies, authenticates, and optionally encrypts data at the IP packet level. For more information about IPSec, see Windows Help and Support.

If you are encoding content for broadcast from a Windows Media server, see the Windows Media Services Help for information about security and the Windows Media server.

Achieving optimal system performance

To achieve optimal system performance:

Use a computer with fast or multiple processors. Because high-quality encoding requires more computing power, use a computer with a fast processor or multiple processors, especially for live events. Windows Media Encoder can use up to two processors for audio, and up to four for video to efficiently distribute the encoding load. If you are using the Windows Media Video 9 codec, you can also adjust performance settings to ensure encoding success. As a general rule, if you find that you continually reach or exceed 80 percent of the CPU load (as indicated on the General tab of the Monitor panel), you may want to consider upgrading your computer.

Use supported audio and video cards. For a complete list of supported cards, see the Microsoft Web site.

Use Microsoft Windows XP Professional. Windows XP Professional takes full advantage of a multiprocessor computer by automatically spawning separate threads to enable processes to run different parts of their programs on different processors simultaneously. This parsing of the work enables you to perform high-end encoding tasks without maximizing your CPU usage.

Check your network bandwidth. It is rare that you will achieve 100 percent throughput when sending content over a network. For optimal results, ensure that your network can accommodate the aggregate bandwidth required by your broadcast session plus the overhead for HTTP.

Use a high-performance hard disk. For archiving or file conversion, use a high-performance hard disk, such as a small computer system interface (SCSI) hard disk with 15,000 rotations per minute. Using a high-performance hard disk can help to offload performance requirements from the main CPU, freeing up more processing power for encoding. In addition, it is useful to use the hard disk only for encoding purposes.

Keep the encoder on a dedicated computer. If you are streaming content from a server running Windows Media Services, it is recommended that you run the encoder on a separate computer from the Windows Media server.

Turn off video preview and postview. The Input and Output areas in the main encoder window show you what your content looks like before and after it is encoded. Turning off these displays improves encoding performance. Or, to achieve a minor performance improvement, you can reduce the views.

Store captured content temporarily. If you are encoding to a file while sourcing from devices, store the content to a hard disk temporarily. In addition, use a different hard disk than the one dedicated to encoding.

Adjusting encoder performance settings

Encoding is a CPU-intensive process. If you continually exceed the capabilities of your encoding computer, you can review the most recent hardware and software requirements to determine if you should upgrade to a more powerful computer. If upgrading is not feasible, however, you can adjust encoder performance settings to ensure success with encoding. (The settings only apply to sessions in which you use the Windows Media Video 9 codec.) Your performance choices are whether to place emphasis on better performance or on better quality. A better performance setting corresponds to lower CPU usage; a better quality setting corresponds to higher usage of the CPU power. Keep the following in mind when choosing performance settings:

If the amount of time needed to encode is not important, you can use the better quality setting. This is most appropriate for a scenario in which you are both sourcing from a file and encoding to a file. The encoder takes as much time as needed to encode.

If it is important that encoding keep pace with capturing, then use the better performance setting. This is appropriate for a scenario in which you are broadcasting, or for a scenario in which you are sourcing from devices and encoding to a file. For the encode-to-file scenario, you can also enable temporary storage for the captured content. With temporary storage, captured data is stored temporarily if the encoding process falls behind the capturing process.

For all of the scenarios, you may want to try different performance settings to find the balance between quality and performance for your computer. Keep in mind that other factors affect CPU usage during encoding. For example, session settings such as frame rate, bit rate, and frame size affect how much work the CPU needs to perform encoding. In addition, other programs running on the encoding computer leave less processing power for the encoder.

Best practices for compression settings

There is a balance between a number of compression settings. The encoder includes many predefined destination, video, and audio settings (profiles) that have already taken this balance into consideration. You can easily set up an encoding session using a predefined profile. However, if you want to customize the settings, then the following paragraphs provide information about the settings, including some of the tradeoffs to consider.

Buffer. A larger buffer can accommodate a better image quality, but the user must wait longer for the video to start, as a player waits to play until its buffer is filled. Typically, the buffer delay matches the time, in seconds, of the buffer size set in the encoder. However, if you plan to stream from a Windows Media server, you can set a larger buffer size in the encoder. A feature in Windows Media Services, called Fast Start, enables a player to fill its buffer faster than real time, assuming there is sufficient bandwidth. This means that the initial buffer delay may be much shorter. For example, when a user attempts to play back 56-Kbps encoded content on a DSL or cable modem, the start-up delay may be only a second or two, even if the buffer size set during encoding was much longer. For more information about Fast Start, see Windows Media Services Help.

If you have set up a session that uses peak bit rate-based VBR encoding for audio, the peak buffer size for audio should be lower than the buffer size for video (if you are using CBR encoding for video) or peak buffer size for video (if you are using peak bit rate-based encoding for video).

Bit rate. A higher bit rate achieves a better image quality. If the bit rate setting is too low, the codec will drop frames to produce a higher quality image, although this may not be visible to the viewer. (Note that if you are encoding low-motion video, the actual bit rate may be significantly lower than the expected bit rate.)

Frame rate. There is a tradeoff between image quality and frame rate, in that as the image quality increases, the frame rate decreases. If maintaining the frame rate is more important, you can decrease the image quality setting.

Image quality (smoothness). You can adjust the image quality to be smoother or more clear. Increasing the clarity can affect the frame rate, depending on the video. For example, if your video contains a lot of motion, increasing the clarity may decrease the frames rate. In addition, increasing the clarity results in a higher bit rate requirement and may also necessitate increasing the buffer size.

Frame size. The larger the frame size, the higher the bit rate requirement.

Key frames. If you use a longer key frame distance, additional key frames are inserted when necessary; for example, when a scene changes. For low motion content, a setting of 20 seconds is typically appropriate. For higher bit rate content, you should lower the key frame distance.

Codecs. Use the appropriate codec for the session. For example, when your audio source is voice or primarily voice, use the Windows Media Audio 9 Voice codec. For a screen capture session, use the Windows Media Video 9 Screen codec.

Two-pass encoding. You will typically achieve higher quality with two-pass encoding, because the encoder has the opportunity to analyze the content during the first pass.

Video resizing. Set up the output frame size to be the same as the input frame size. Do not use the encoder to resize the source video.

Running multiple encoders on one computer

You can run multiple instances of Windows Media Encoder on a single computer provided the computer is powerful enough to support them. By running multiple instances of the encoder, you can:

Simultaneously broadcast separate streams at different bit rates.

Simultaneously convert multiple files to Windows Media Format.

Use a multiple-port device as your source, and then stream the encoded content from each port to different locations.

If you decide to run multiple encoders on one computer, keep in mind that input devices can be used by only one process at a time, so you might want to install several audio and video capture cards. For optimal performance, use a computer with two or more processors.

Batch encoding

If you want to encode multiple audio and video files, you can use Windows Media Encoding Script, which is included with Windows Media Encoder. Or, you can automate the encoder for batch encoding by using a script and Windows Script Host.

For more information about Windows Script Host and batch encoding, see the Windows Media Encoder 9 Series SDK.

Frequently asked questions and troubleshooting

For up-to-date information about working with the encoder, see the Windows Media page at the Microsoft Web site.

Technical support options

The services and prices listed in the following table are available in the United States only. Support outside the United States may vary, the worldwide Web site listed in the table for regional contact details. Microsoft's support services are subject to Microsoft's then-current prices, terms, and conditions, which are subject to change without notice.

Item	Description
Online support information	For general questions, visit the Microsoft Web site, or in Canada, visit the Microsoft Web site. For articles targeted at specific issues, visit the Microsoft Knowledge Base. To work with a Microsoft Support Professional over the Internet, you can submit an online request form at the Microsoft Web site. For the general support policy, visit the options page at the Microsoft Web site.
Phone support	For Paid Assisted Support, call (800) 936-5700 in the United States or (800) 668-7975 in Canada. You can also call (425) 637-9308 in the United States, or (905) 568-3503 in Canada (toll charges may apply).
TTY service	Microsoft text telephone (TTY/TDD) services are available at (425) 635-4948 in Washington state or (800) 892-5234 in the United States. In Canada, call (905) 568-9641.
Worldwide	Support outside the United States and Canada may vary. For regional contact details, visit the international page at the Microsoft Web site. If there is no Microsoft subsidiary office in your country or region, please contact the establishment from which you obtained Windows Media Encoder.

Accessibility for people with disabilities

Microsoft is committed to making its products and services easier for everyone to use. The following topics provide information about the features, products, and services that make Microsoft Windows Media Encoder more accessible for people with disabilities:

Accessibility features in Windows Media Encoder

Accessibility features in Windows Media Encoder Help

Accessible products and services from Microsoft

Note

The information in this section applies only to users who license Microsoft products in the United States. If you obtained this product outside the United States, your package contains a subsidiary information card listing Microsoft support services telephone numbers and addresses. You can contact your subsidiary to find out whether the products and services described in this section are available in your area. Accessibility information is available in other select languages, including Japanese and French. For more information, see the Microsoft Web site.

Accessibility features in Windows Media Encoder

In addition to accessibility features and utilities in Windows, the following feature makes Windows Media Encoder more accessible for people with disabilities:

Using keyboard shortcuts

By using the following keyboard shortcuts in Windows Media Encoder, you can quickly accomplish many common tasks.

To do this.	Use this keyboard shortcut.
Display context-sensitive Help.	F1
Move forward through the options on a dialog box or property sheet.	TAB
Move backward through the options on a dialog box or property sheet.	SHIFT+TAB
Scroll up one item in a spin box or drop-down list.	UP ARROW
Scroll down one item in a spin box or drop-down list.	DOWN ARROW
Scroll forward through tabs.	RIGHT ARROW
Scroll backward through tabs.	LEFT ARROW
Refresh the current dialog box or control (refresh plug-in list, refresh playlist view).	F5 or CTRL+R
Dismiss property sheet or dialog box or cancel out of a wizard.	ESC
Carry out the command for the active option or button	ENTER
Cut the selected items and copy them to the Clipboard.	CTRL+X
Copy the selected items to the Clipboard.	CTRL+C
Paste the contents of the Clipboard at the selected location.	CTRL+V
Display or hide the Session Properties panel.	ALT+ENTER
Close current window.	ALT+F4
Display shortcut menu.	SHIFT+F10
Select or clear the selection of an item.	SPACEBAR
Display context menu.	Application Key
Switch to High Contrast mode.	LEFT ALT+LEFT SHIFT+PRINT SCREEN

Accessibility features in Windows Media Encoder Help

Windows Media Encoder Help includes features that make it accessible to a wider range of users, including those who have limited dexterity, low vision, or other disabilities.

In addition, Windows Media Encoder Help is available on the Web at the Microsoft Web site.

Keyboard shortcuts for using the Help window

By using the following keyboard shortcuts in Help, you can quickly accomplish many common tasks.

To do this.	Use this keyboard shortcut.
Display the Help window.	F1
Switch between the Help topic and the Contents, Search, and Index tabs.	F6
Select the next hidden text or hyperlink.	TAB
Select the previous hidden text or hyperlink.	SHIFT+TAB
Perform the action for the selected Show All, Hide All, hidden text, or hyperlink.	ENTER
Display the Options menu to access any Help toolbar command.	ALT+O
Hide or show the pane containing the Contents, Search, and Index tabs.	ALT+O, and then press T
Display the previously viewed topic	ALT+O, and then press B
Display the next topic in a previously displayed sequence of topics.	ALT+O, and then press F
Return to the specified home page.	ALT+O, and then press H
Stop the Help window from opening a Help topic (useful if you want to stop a Web page from downloading).	ALT+O, and then press S
Open the Internet Options dialog box for Microsoft Internet Explorer, where you can change accessibility settings.	ALT+O, and then press I
Refresh the topic (useful if you have linked to a Web page).	ALT+O, and then press R
Print all topics in a book or a selected topic only.	ALT+O, and then press P
Close the Help window.	ALT+F4

Accessible products and services from Microsoft

The following topics provide information about the features, products, and services that make this Microsoft product more accessible for people with disabilities:

Accessibility in Microsoft Windows

Adjusting Microsoft products for people with accessibility needs

Free step-by-step tutorials

Microsoft documentation in alternative formats

Assistive technology for Windows

Customer service for people who are deaf or hard-of-hearing

Getting more accessibility information

The information in this section applies only to users who license Microsoft products in the United States. If you obtained this product outside the United States, your package contains a subsidiary information card listing Microsoft support services telephone numbers and addresses. You can contact your subsidiary to find out whether the type of products and services described in this section are available in your area. Accessibility is available in other select languages, including Japanese and French. For more information, see the Microsoft Web site.

Accessibility in Microsoft Windows

Many accessibility features have been built into Microsoft Windows, starting with the introduction of Windows 95. These features are useful for individuals who have difficulty typing or using a mouse, are blind or have low vision, or who are deaf or hard-of-hearing. The features can be installed during setup. For more information about the various accessibility features of Microsoft Products, such as Microsoft Windows XP Professional, Windows XP Home Edition, Windows Millennium Edition, Windows 2000, Windows 98, and Windows 95, see the Microsoft Web site.

Adjusting Microsoft products for people with accessibility needs

Accessibility options and features are built into many Microsoft products, including the Windows operating system. Accessibility options and features are useful for individuals who have difficulty typing or using a mouse, are blind or have low vision, or who are deaf or hard-of-hearing.

Free step-by-step tutorials

Microsoft offers a series of step-by-step tutorials to help you learn how to adjust the accessibility options and settings on your computer. The tutorials provide detailed procedures on how to adjust options, features, and settings to meet the needs of people with disabilities and accessibility needs. This information is presented in a side-by-side format so that you can see at a glance how to use the mouse, the keyboard, or a combination of both.

To find step-by-step tutorials for Microsoft products, see the Accessibility section of the Microsoft Web site.

Microsoft documentation in alternative formats

In addition to the standard formats, documentation for many Microsoft products is available in other formats to make it more accessible. If you have difficulty reading or handling printed materials, you can obtain the documentation for many Microsoft products in other, more accessible formats. You can download many of these books from the Microsoft Web site.

Microsoft produces an index of accessible documentation on the Accessibility section of the Microsoft Web site.

In addition, you can obtain additional Microsoft publications from Recording for the Blind & Dyslexic, Inc. These documents are distributed to registered, eligible members of their distribution service on audiocassettes or on floppy disks. The collection contains more than 80,000 titles, including Microsoft product documentation and books from Microsoft Press. For information about eligibility and availability of Microsoft product documentation and books from Microsoft Press, contact:

Recording for the Blind & Dyslexic, Inc.
20 Roszel Road
Princeton, NJ 08540

Phone from within the United States: (800) 221-4792
Phone from outside the United States and Canada: (609) 452-0606
Fax: (609) 987-8116

Recording for the Blind & Dyslexic Web site

Web addresses can change, so you might be unable to connect to the Web site or sites mentioned here.

Assistive technology for Windows

A wide variety of accessibility aids, or assistive technology products, are available to make computers easier to use for people with disabilities.

Microsoft provides a searchable catalog of accessibility aids that run on Microsoft Windows operating systems at the Accessibility section of the Microsoft Web site.

Among the different types of products available for the MS-DOS, Windows, and Windows NT operating systems are:

Programs that enlarge the information displayed or alter the color of information on the screen for people with visual impairments.

Programs that describe information on the screen in Braille or synthesized speech for people who are blind or have difficulty reading.

Hardware and software utilities that modify the behavior of the mouse and keyboard.

Programs that enable people to type by using a mouse or their voice.

Word or phrase prediction software that enable users to type more quickly and with fewer keystrokes.

Alternative input devices, such as single switch or puff-and-sip devices, for people who cannot use a mouse or a keyboard.

Upgrading

If you use assistive technology, before you upgrade either your software or hardware, be sure to contact your assistive technology vendor to check compatibility with products on your computer. Your assistive technology vendor can also help you learn how to adjust your settings to optimize compatibility with your version of Windows or other Microsoft products.

Customer service for people who are deaf or hard-of-hearing

If you are deaf or hard-of-hearing, complete access to Microsoft product and customer services is available through a text telephone (TTY/TDD) service.

Customer service

You can contact Microsoft Sales Information Center on a text telephone by dialing (800) 892-5234 between 6:30 AM and 5:30 PM Pacific time, Monday through Friday, excluding holidays.

Technical assistance

For technical assistance in the United States, you can contact Microsoft Product Support Services on a text telephone at (800) 892-5234 between 6:00 AM and 6:00 PM Pacific time, Monday through Friday, excluding holidays. In Canada, dial (905) 568-9641 between 8:00 AM and 8:00 PM Eastern time, Monday through Friday, excluding holidays. Microsoft support services are subject to the prices, terms, and conditions in place at the time the service is used.

Getting more accessibility information

The Accessibility section of the Microsoft Web site provides information about accessible technology to help improve the lives of people with disabilities by making computers a positive force in employment, education, and recreation. The information on this site benefits people with disabilities and their friends and family members, people in outreach organizations, educators, and advocates.

A free monthly newsletter is offered through e-mail to help you keep up to date with accessibility topics about Microsoft products at the Accessibility section of the Microsoft Web site.

Glossary

To find a term in the glossary, click the letter of the alphabet that is the first letter in the term you want to look up.

You can also read glossary terms within the text of Help by clicking the underlined glossary term links. After you click a glossary link, the glossary term and definition appear in a pop-up window. To close the window, click anywhere on the screen.

A	B	C	D	E	F	G	H	I	J	K	L	M
N	O	P	Q	R	S	T	U	V	W	X	Y	Z

P

.prx

The file name extension of a profile.

Symbols

.weu

The file name extension of a configuration file used by Windows Media Encoding Script.

.wma

The file name extension of an audio file in Windows Media Format. The audio content of the file is encoded with the Windows Media Audio codec.

.wme

The file name extension for a Windows Media Encoder session file.

.wmv

The file name extension of a video file in Windows Media Format.

A

announcement

A Windows Media metafile that gives a player the information needed to receive content. Announcement files contain Extensible Markup Language (XML) scripts.

aspect ratio

The ratio of the width of an image to its height.

Audio Video Interleaved (AVI)

A multimedia file format for storing sound and moving pictures in RIFF format.

AVI

See definition for: Audio Video Interleaved (AVI)

B

bandwidth

A network's capacity for transferring an amount of data in a given time.

bit rate

The number of bits transferred per second.

C

caption

Text that accompanies images or videos, either as a supplemental description or a transcript of spoken words.

CBR

See definition for: constant bit rate (CBR)

codec

An abbreviation for compressor/decompressor. Software or hardware used to compress and decompress digital media.

compression

A process for removing redundant data from a digital media file or stream to reduce its size or the bandwidth used.

configuration file

A text file used by Windows Media Encoding Script that specifies the content to be encoded and the command-line options to be invoked.

constant bit rate (CBR)

A characteristic of a data stream in which the bit rate remains nearly uniform for the duration of the stream.

See also: variable bit rate (VBR)

content

Audio, video, images, text, or any other information that is contained in a digital media file or stream.

D

deinterlace

To combine the interlaced fields in a video frame so that, during playback, the lines of the video frame are painted sequentially.

See also: interlace

delta frame

A video frame that contains only the changes from the previous frame. In contrast, a key frame contains all the data necessary to construct that frame.

dynamic range

The difference (in decibels) between the quietest and loudest sounds in a single piece of audio content.

E

encode

To convert audio and video content to a specified digital format.

F

frame rate

The number of video frames displayed per second. Higher frame rates generally produce smoother movement in the picture.

H

header

A part of the file structure that contains information required by an application to decompress and render the content. The header in a protected file also contains information required to get a license.

I

IEEE 1394

See definition for: Institute of Electrical and Electronics Engineers (IEEE) 1394

Institute of Electrical and Electronics Engineers (IEEE) 1394

A high-speed serial bus standard that provides enhanced computer connectivity for a wide range of devices, including consumer electronics audio/video (A/V) appliances, storage peripherals, other computers, and portable devices.

intelligent streaming

A type of streaming that detects network conditions and adjusts the properties of a video or audio stream to maximize quality.

interlace

To display a video frame in two fields. One field contains the even lines of the frame, the other field contains the odd lines. During playback, the lines in one field are displayed first, then the lines in the second field are displayed.

Internet Protocol version 6 (IPv6)

A revised version of the Internet Protocol (IP) designed to address growth on the Internet. Improvements include a 128 bit IP address size, expanded routing capabilities, and support for authentication and privacy.

inverse telecine

The process that removes the frames that were added when 24-fps film was converted to 30-fps video.

IPv6

See definition for: Internet Protocol version 6 (IPv6)

K

key frame

A video frame containing all the data needed to construct an image without reference to previous frames.

See also: delta frame

L

latency

The delay that occurs while data is processed or delivered.

letterbox

A video display format in which black bars appear above and below the video image while it is played. The letterbox format maintains the original aspect ratio of an image when it is displayed in a window with a different aspect ratio.

license

Data attached to protected content that describes how the content can be used.

loop

To repeat a stream continuously.

lossless compression

A process for compressing data in which information is arranged in a more concise form and restored to its original state upon decompression.

lossy compression

A process for compressing data in which information deemed unnecessary is removed and cannot be recovered upon decompression. Typically used with audio and visual data in which a slight degradation of quality is acceptable.

M

marker

A text string that is associated with a designated time in Windows Media-based content. Markers often denote convenient points to begin playback, such as the start of a new scene.

MBR

See definition for: multiple bit rate (MBR)

metadata

Data about data. Title, subject, author, and size are examples of a file's metadata.

multicast

A content delivery method in which a single stream is transmitted from a media server to multiple clients. The clients have no connection with the server. Instead, the server sends a single copy of the stream across the network to multicast-enabled routers, which replicate the data. Clients can then receive the stream by monitoring a specific multicast IP address and port.

multichannel audio

An audio reproduction system that processes several, typically more than two, channels of sound. For example, 5.1 multichannel audio refers to a surround sound system in which there are five primary channels and a subwoofer channel.

multiple bit rate (MBR)

A characteristic of a data stream in which the same content is encoded at several different bit rates in order to optimize content delivery.

N

National Television Standards Committee (NTSC)

The dominant television standard in the United States and Japan. NTSC delivers 30 interlaced frames per second at 525 lines of resolution.

NTSC

See definition for: National Television Standards Committee (NTSC)

O

one-pass encoding

An encoding method in which content is analyzed and compressed in the same pass through the encoder.

See also: two-pass encoding

PAL

See definition for: Phase Alternating Line (PAL)

PCM

See definition for: pulse code modulation (PCM)

Phase Alternating Line (PAL)

The dominant television standard in Europe and China. PAL delivers 25 interlaced frames per second at 625 lines of resolution.

pixel format

The size and arrangement of pixel color components. The format is specified by the total number of bits used per pixel and the number of bits used to store the red, green, blue, and alpha components of the color of the pixel.

postroll

To extend the amount of encoded video by a specified number of frames.

preroll

To capture or play a number of video frames or a portion of audio data before encoding or rendering begins, in order to allow the source device to stabilize. Also used as a noun to describe the portion of the data to be prerolled.

profile

A group of settings that match content type and bit rate with appropriate audio and video codecs.

Profile Editor

A tool provided with Windows Media Encoder that creates and edits the encoding profiles.

See also: profile

publishing point

An organized memory location that translates a client request for content into the physical path on the server hosting the content. A publishing point essentially acts as a redirector.

pull

To deliver data to a client only upon client request.

pulse code modulation (PCM)

A technique for digitizing audio into an uncompressed format by assigning a value to the amplitude of the signal at fixed intervals.

push

To deliver data to a client without a client request for the data.

R

RGB

A color model that describes color information in terms of the red (R), green (G), and blue (B) intensities that make up the color.

S

sampling

The process of measuring the amplitude of an analog signal at regular intervals for the purpose of converting the signal into a digital format.

sampling rate

The frequency of sampling. The higher the sampling rate (that is, the more samples taken per unit of time), the more closely the digitized result resembles the original.

script commands

Named data that is associated with a designated time in Windows Media-based content. The data can be used by players to perform a specific action such as displaying a Web page.

source

Audio and video content that can be captured and encoded from devices installed on your computer or from a file.

stream

Digital media that is in the process of being delivered in a continuous flow across a network.

stream format

Information about the properties of a stream, such as the codecs used, frame rate, and frame size. A player uses stream format information to decode a stream.

stream format file

A file used by a player to decode a multicast stream.

See also: stream format

T

telecine

The film-to-video conversion system that adds frames to video to compensate for the differences in frame rates between film and video.

time code

A digital signal applied to a stream. The signal assigns a number to every frame of video, representing hours, minutes, seconds, and frames.

two-pass encoding

An encoding method in which content is analyzed in one pass through the encoder, after which compression is applied in the second pass. See also one-pass encoding.

U

UDP

See definition for: User Datagram Protocol (UDP)

UNC

See definition for: Universal Naming Convention (UNC)

unicast

A method used by media servers for providing content to connected clients in which each client receives a discrete stream. No other client has access to that stream.

Universal Naming Convention (UNC)

The full name of a resource on a network. It conforms to the \\servername\sharename syntax, where servername is the name of the server and sharename is the name of the shared resource. UNC names of directories or files can also include the directory path under the share name, with the following syntax: \\servername\sharename\directory\filename.

User Datagram Protocol (UDP)

A connectionless transport protocol in the TCP/IP protocol stack that is used in cases where some packet loss is acceptable, for example, with digital media streams.

V

variable bit rate (VBR)

A characteristic of a data stream in which the bit rate fluctuates, depending upon the complexity of the data.

VBR

See definition for: variable bit rate (VBR)

W

Windows Media Audio codec

A codec used to compress and decompress audio streams.

Windows Media file

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.

Windows Media Format

The format used by Microsoft Windows Media Technologies (or a third-party product that incorporates a licensed Windows Media technology) to author, store, edit, distribute, stream, or play timeline-based content.

Windows Media metafile

In Windows Media Technologies, a file that provides information about Windows Media files and their presentation. File name extensions for Windows Media metafiles include .asx, .wax, .wvx, .wmx, and .nsc.

Windows Media Screen codec

A codec used to compress and decompress sequences of screen images.

Windows Media Video codec

A codec used to compress and decompress video streams.

Y

YUV

A color model that describes color information in terms of its brightness (luminance, or Y), and color (chrominance, or U and V).

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Windows Media Encoder

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Table of Contents

Windows Media Encoder

Getting started

Related topics

Encoding with quick starts or the New Session Wizard

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Using quick starts to encode

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Using the New Session Wizard to encode

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What's new

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Feature requirements

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Hardware and software requirements

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About encoder views

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About the encoder utilities

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Documentation conventions

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Concepts

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Understanding codecs

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About sessions

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Comparing Windows Media servers and Web servers

Windows Media servers

Web servers

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About CBR or VBR encoding

CBR encoding

VBR encoding

Encoding mode options

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About one- or two-pass encoding

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Configuring sources

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Sourcing from a file

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Sourcing from multichannel audio files

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Sourcing from devices

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Enabling device control

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Setting up an EDL

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Capturing screens

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Improving performance when encoding screens

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Inserting script commands

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Using multiple sources in a session

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Customizing a session

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