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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

Symbols

.prx

The file name extension of a profile.

.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.

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A

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)

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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.

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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.

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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.

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E

encode

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

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F

frame rate

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

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I

ICM

See definition for: Image Compression Manager (ICM)

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.

inverse telecine

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

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K

key frame

A frame of video data that contains all the data necessary to construct that frame. In contrast, delta frames contain data relating to changes from the last key frame, and do not contain enough information to construct a complete frame.

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L

looping

In Windows Media Encoder, repeatedly playing a file until all content is encoded. For example, an audio track can be looped while a video file is being encoded.

lossless compression

Data compression techniques in which no data is lost.

lossy compression

Data compression techniques in which some amount of data is lost. Lossy compression technologies attempt to eliminate redundant or unnecessary information. Reducing the file size of an image in this way can degrade the quality of the image.

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M

marker

A pointer to a specific place, measured in time, in a Windows Media file. Windows Media Player uses markers to go directly to a point in the file. Markers enable viewers to skip ahead or skip back to a marker in order to see a particular part of the file again.

MBR

See definition for: multiple bit rate (MBR)

metadata

Data about data. For example, the title, subject, author, and size of a file constitute the file's metadata.

Microsoft MPEG-4 version 3 codec

A video codec included with Microsoft Windows Media Encoder.

multicast

A method of distributing content in which multiple clients share a stream from a server.

multiple bit rate (MBR)

Describes a file or stream that contains the same content encoded at several different bit rates. As network traffic changes, a server running Windows Media Services can switch to a lower or higher bit rate to optimize content delivery.

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N

National Television Standards Committee (NTSC)

A standards body that is responsible for setting television and video standards in the United States. The NTSC standard for television defines a composite video signal with a refresh rate of 60 half-frames (interlaced) per second. Each frame contains 525 lines and can contain 16 million different colors. Formerly the National Television Systems Committee.

NTFS

An advanced file system designed for use specifically within the Windows 2000 operating system. It supports file system recovery, extremely large storage media, and long file names. It also supports object-oriented applications by treating all files as objects with user-defined and system-defined attributes.

NTSC

See definition for: National Television Standards Committee (NTSC)

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O

one-pass encoding

The ability to pass content through the encoder once. Compression is applied as the content is encountered.

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P

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. Whereas the NTSC, the U.S. standard, delivers 525 lines of resolution at 60 half-frames per second, PAL delivers 625 lines at 50 half-frames per second.

pixel format

The color depth of an image, usually measured in RGB or YUV.

postroll

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

preroll

To queue video by a specified number of frames so that the source tape is stabilized before encoding begins.

profile

A predefined 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 needed to identify the appropriate codec, the multimedia input streams, and the number and bit rate of the encoded output streams.

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.

Pulse Code Modulation (PCM)

A sampling technique for digitizing analog signals, especially audio signals. When you encode audio by using PCM, no compression is applied.

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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.

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S

sampling rate

The frequency at which audio or video is sampled, or recorded, into a digital format. Each sample represents the audio or video signal at a particular moment in time. 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

Software instructions that can be included with an encoded stream. Windows Media Player passes script commands to a device or software that interprets them. Script commands are used for such tasks as calling specific files or navigating to a specific Web site.

source

Content that you can encode. Source audio and video content can be captured and encoded from devices installed on your computer or from a file.

startup latency

The time it takes for the encoder, SDK reader, or other devices to start before encoding begins. Startup latency prevents the cutting of frames at the mark-in point.

stream

Data transmitted across a network and any properties associated with the data. Streaming digital data enables clients to begin rendering the data immediately instead of waiting for the entire file to be received.

stream format file

A file used by a player to decode a multicast stream. A stream format file includes information about the stream, the digital media content, and its associated codec.

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T

target bandwidth

The number of bits that are transferred to users based on their network connection speeds.

telecine

The film-to-video conversion system that adds frames to video to compensate for the differences in frame rates between film and video. When converting 24 fps film to 30 fps NTSC video, an additional 6 frames per second are added.

transcode

To encode content that is already in Windows Media format, but at a different bit rate.

two-pass encoding

The ability to pass content through the encoder twice. During the first pass, the encoder analyzes the content. During the second pass the encoder applies the appropriate levels of compression, based on the complexity of the material, as determined during the first pass.

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U

UDP

See definition for: User Datagram Protocol (UDP)

UNC

See definition for: Universal Naming Convention (UNC)

unicast

A method of providing content in which each client receives a unique stream from a server; no other client has access to the stream.

Universal Naming Convention (UNC)

The system of naming files among computers on a network so that a file on a specified computer has the same path when accessed from any of the other computers on the network. For example, if the directory C:\Path1\Path2\...Pathn on computer Servern is shared under the name Pathdirs, a user on another computer must open \\Servern\Pathdirs\Filename.ext to access the file C:\Path1\Path2\...Pathn\Filename.ext on Servern.

User Datagram Protocol (UDP)

A connectionless transport protocol in the TCP/IP protocol stack that, like TCP, runs on top of IP networks.

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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)

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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 Speech codec

A codec used to compress and decompress audio streams with an emphasis on speech.

Windows Media Video codec

A codec used to compress and decompress video streams.

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Y

YUV

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

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