Glossary

3GPP
3GPP is the abbreviation for “Third Generation Partnership Project”. The project is a co-operation of several telecom organisations. 3GPP was formalized in 1998 with the intention to define standards for mobile multimedia communications. For more information, see also www.3gpp.org.

3GP File
A 3GP file is specified in the 3GPP standardisation and designed for utilisation in the mobile sector. It is essentially based on the MP4 file format.

A

AAC (Advanced Audio Codec)
AAC is an audio codec and specified in the MPEG-4 standard. AAC is an optional audio codec in the 3GPP specification and the mandatory audio codec in MPEG-4. See also http://www.chiariglione.org/mpeg/faq/mp4-aud/mp4-aud.htm.

AAC+
AAC+ is a label used by codec and mobile manufacturers referring to HE-AAC.

ABR (Average bit rate)
ABR is the result of a compression technique that allows periodical variation of the bit rate like VBR (variable bit rate) but is geared to a relatively stable bit rate throughout the whole encoding process. Hence ABR allows calculating the final data size of the encoded material. To attain an ABR as exact as possible some encoders do two-pass encoding.

AC-3
AC-3 is an audio codec developed by Dolby Laboratories and used in most cinemas and on DVDs. For further information, please visit www.dolby.com.

ADSL (Asymmetric Digital Subscriber Line)
ADSL is high speed, always-on Internet connectivity provided through regular copper telephone lines. Most offers available are based on flat fee subscriptions. Asymmetric stands for the fact that ADSL supports different data rates for the upstream and downstream.

AMR (Adaptive Multi Rate)
AMR is an audio codec for very low bit rates, which was standardised by the European Telecommunications Standards Institute (ETSI) in 1999. AMR is an optional audio codec in the 3GPP specification.

API (Application Programming Interface)
API stands for a function (or a variety of functions) enabling software users, especially developers, to interact with other software, especially in a development environment (usage in Software Developers Kits).

ASP (Application Service Provider)
An ASP is a commercial entity that offers access to specific software applications over Internet connections on a rental and/or pay-as-you-go basis for a specific period of time.

ASP (Advanced Simple Profile)
The Advanced Simple Profile is a profile defined in MPEG-4 part 2 (visual). It is a superset of the Simple Profile (SP) and provides additional tools. ASP supports B-frames, quarter pixel accurate motion vectors, global motion compensation (GMC) and interlaced coding modes. The ASP achieves a higher coding efficiency compared to SP with the downside of a higher computational complexity of encoder and decoder. For a comparison of ASP and SP see http://www.m4if.org/public/documents/vault/m4-out-30037.pdf

ATSC (Advanced Television Systems Committee)
The ATSC is a non-profit organisation established for the development of terrestrial digital television standards for the United States. For further information, please visit www.atsc.org.

Audio Channels
Audio channels are the number of more or less independent audio streams. Mono sound uses one audio channel, stereo uses two audio channels.

Audio Sample Rate
Audio sample rate is the number of sample values per second used to represent an audio signal by time discrete values. The higher the sample rate, the better is the sound. Higher sample rates result in a bigger file size and higher bit rate. Typical sample rates for consumer devices such as a music CD is 44.1 kHz. Professional audio equipment uses 48 kHz. Cutting edge digital recording studios are currently moving on to 96 kHz. Digital radio services often use 35 kHz sample rate, which is considered to provide sufficient bandwidth for radio.

Automatic Update
Allows the automatic download, and in many cases, the installation of updates or plug-in software without user interference (i.e., no Web browser needs to opened and the installation happens “in the background”).

AVC
AVC (Advanced Video Codec) is a synonym for MPEG-4 Part 10 or H.264. All three denotations, AVC, MPEG-4 part 10 and H.264, mean exactly the same standard.

AVI File
Short for Audio Video Interleave, the file format for Microsoft's Video for Windows architecture. This is, in fact, a very old specification that Microsoft is not really supporting anymore. Actually, AVI has not been formally been specified, but happened to be around at some point in time. The format has become so ubiquitously used that it will live on for quite some time even outside the control of Microsoft.

B

B-Frame
B-frames have their name from being bi-directionally predicted from at least two reference frames. That means for decoding a B-frame at time instant k the previous frame at time instant k-1 and the next frame at time instant k+1 are needed.
Even though B-frames are based on predictions coming from two neighboring frames a B-frame is not itself used as a reference frame for predicting other frames. This would lead to an aggregation of coding errors, which kills coding efficiency or image quality. B-frames are an effective video coding tool to improve coding efficiency. All coding schemes offering premium coding performance have a B-frame mechanism employed. However, using B-frames for coding requires more memory in the encoder and in the decoder as an extra frame (reference frame 2) needs to be stored during the decoding process. Furthermore, B-frames introduce extra delay, which is unacceptable for example in conversational applications. There, no B-frames are used. This holds for H.263 and its precursors as well as for MPEG-4 Simple Profile. For television services based on MPEG-2, there are typically 2 successive B-frames between two reference frames to further increase coding efficiency. Another price to be paid by B-frames is that frame exact editing in the coded bit stream is no longer possible. In order to reconstruct the B-frame, both reference frames are needed. If either one of them is gone due to cutting the video material, the B-frame is gone as well. In MPEG, the reference frames for coding a B-frame can either be P-frames or I-frames.

Bandwidth
In simple terms, bandwidth can be compared, for example, with the diameter of a water pipe. The larger the diameter, the more water gets through. By definition, bandwidth describes the amount of bits that can be transmitted over a network connection over a specific period of time (for example kbits per second, etc.).

Bit
Bit is the abbreviation for binary digit and can either be 0 or 1. There is no other data description mechanism in technology that is smaller than a bit.

Bit Rate
Bit rate is described as the rate with which bits can be transmitted over a specific period of time.

Block Matching
Block matching is an algorithm-based operation that is locating consistent bundles of pixels (blocks) within subsequent video frames. Although the position of a block within a frame might change because of movements or camera panning the block itself stays very much the same and hence doesn’t have to be encoded completely anew. Only the differences from one frame to another have to be encoded. In consequence the location of those matching blocks can increase coding efficiency.

BPS
BPS is the abbreviation for bits per second.

Broadband
Broadband comes in a variety of flavours, such as, for example DSL, ADSL, or cable, and they are high-speed, always-on Internet connections that are much faster than traditional Internet connections such as Dial-up or ISDN. Broadband is now very much deployed around the globe to business and homes alike.

Buffering
When streamed media enters a user’s computer faster than it can be played back, it is saved in memory without burdening the player too much.

Byte
Short form for “binary term.” One byte is made of eight bits, which is approximately the amount needed by a computer to store a typed number or letter.

C

Capture Device
A capture device transforms analogue audio or video data to digital data.

CBR (Constant Bitrate)
In video coding, the bit rate of the compressed video is fixed as a certain rate. This usually results in variable perceived quality of the video.

CELP
CELP is one of the most technically advanced audio compression algorithms. It is part of the MPEG-4 specifications. See also http://www.chiariglione.org/mpeg.

CIF (Common Interchange Format)
CIF is a video resolution, the so called “common interchange format.” The size is 352 x 288 pixels.

Codec (Compression Decompression Algorithm)
A codec is a program which encodes and decodes digital data with the purpose of data compression.

Color Formats
When video data is stored digitally there are several different formats to store the color value of a pixel. For example, RGB24, RGB32, and YUY2 are often used.

Content Delivery Network (CDN)
A content delivery network (CDN) provides network architecture for the guaranteed delivery of broadcast content or other value added services. This infrastructure can also reduce network congestion or excessive burdens on servers.

Compression
Compression is used to reduce the size of a file in order to make it suitable for a required bandwidth or for effective storage. There are two types of compression – lossy and lossless. MPEG standards are lossy compression techniques, where the decompressed file is not totally identical with the original file. An example of lossless compression is ZIP, in which the decompressed file and the original are identical.

Core Profile
Core profile is a set of tools used for video encoding. In MPEG-4, the core profile specifies the coding of non-rectangular objects.

Cropping
Cropping is the process of cutting the borders of a picture or video.

CVBR (Constrained bit rate)
Since streaming with VBR (variable bit rate) may sometimes overstrain the available bandwidth of a channel, a limitation of the maximum allowed bit rate and a fixation of an average bit rate might become necessary. This way of encoding is leading to CBVR.

D

Datacast
A datacast is the one-way delivery/transmission of data from the broadcaster to the viewer. An example for this is digital television.

Deblocking
Deblocking is a process running as part of either the video encoder or the video decoder. The purpose of deblocking is to minimize the detrimental visual effects of block-like artifacts in decoded videos. Those blocking artifacts mainly occur as the video encoder starts to remove relevant visual information. This happens if the bit rate or available bit budget is insufficient to represent the video content and, hence, the quantization is acting too hard on the video samples.

Decimation
Decimation is the application of specific filters to reduce the vertical or horizontal size of a picture or video sequence. The quality of the decimation algorithm heavily impacts the quality of the resulting picture.

Deinterlacing
Deinterlacing denotes the process of inverting the process of interlace (i.e. of putting two images of the half resolution together to one image). This can be done in many different ways, all of them producing various degrees of visually annoying artefacts (cheap deinterlacer) or almost flawless and crisp images with full resolution.

Deringing
Deringing is a process of minimizing the effect of ringlike artefacts in decoded videos.

DirectShow
DirectShow is part of Microsoft's DirectX framework. DirectShow is the media streaming architecture. See also www.microsoft.com.

DirectX
Microsoft DirectX is a set of application programming interfaces (APIs) for creating games and other high-performance multimedia applications. See also msdn.microsoft.com.

DivX
DivX is a widespread video technology that utilises MPEG-4 to compress digital video.

Download
A download is the transmission of data by a user from a remote server over various networks (e.g., the download of media files from over the Internet). Compared to streaming downloading has no real-time constraints.

DRM (Digital Rights Management)
Digital rights management allows content owners to protect their property by applying certain rules and technology. For example, with DRM, content owners can set specific periods of time that viewers can access content or set specific means as to how content can be viewed.

DTV (Digital Television)
Originally “reserved” to describe digital terrestrial broadcasting it is now also used to describe all form of digital television (i.e., which is delivered via cable, etc.). There is also DTV Multicast, which means that a variety of programs are transmitted via a single transmitter, and the viewer can choose from what is offered.

DV
DV is a standard for digital video recording. DV videos can be imported by special DV codecs via FireWire.

DVB
The Digital Video Broadcasting Project (DVB) is an industry-led consortium of over 300 broadcasters, manufacturers, network operators, software developers, regulatory bodies, and others in over 35 countries, who are committed to designing global standards for the global delivery of digital television and data services. For further information, please visit www.dvb.org.

DVD (Digital Versatile Disk)
DVD stands for digital versatile disk and physically looks like a regular CD; however, a DVD can store 4.7 Gigabytes of data.

DVR (Digital Video Recorder)
A DVR is in essence the same as what is known as a video recorder, except that a DVR records media, such as audio and video onto a hard-disk. DVR functions, like play, record, fast forward, etc. are controlled and managed through software.

E

Encoding
Encoding means the transfer of digital media from one format to another.

F

FEC (Forward Error Correction)
Forward error correction is a way of error control that uses redundant data added by the sender to the original data packets. In case of a data loss the redundant data enables the receiver to reconstruct the lost data. FEC does not require any back-channel.

Flash
Flash is a vector graphics-based animation software, which has become a de-facto industry standard when it comes to the development of interactive, rich media Web site content. For more information, please visit www.macromedia.com.

Flash 9
Flash9 is Adobe’s latest version of the Flash format. It includes H.264 and AAC as coding formats. Besides the proprietary FLV file format, now also MP4 file format is supported.

FPS
FPS is an abbreviation for frames per second.

Frame
A frame is a picture of a video. Normally you have 20 to 30 frames per second.

Frame Rate
Frame rate is the number of frames in a specific period of time. The usual measuring unit is frames per second.

G

GMC (Global Motion Compensation)
GMC is an extension of the block-based Motion Compensation. It was introduced with MPEG-4 Part 2’s Advanced Simple Profile. Including the compensation of zooms and camera pannings GMC goes beyond the Motion Compensation of mere movements. Because of its improved motion vector coding syntax H.264 does not require any more a specific mode to compensate global motions.

GoP (Group of pictures)
A GoP (Group of pictures) usually consists of a single I-frame (always on the first position of a GoP) and a larger number of P and B-frames.

H

H.264
H.264 is a synonym for both MPEG-4 Part 10 and AVC (Advanced Video Codec). H.264 is the denotation used in the standard of the International Telecommunication Union (ITU-T).

HD (High Definition)
HD refers to the resolution of digital videos which is higher than SD (Standard Definition) and hence has a better picture quality. HD videos have a resolution of 1080 or 720 horizontal lines. In addition to resolution the scanning system (progressive scanning or interlaced scanning) and the frame rate are quoted. 1080p/50 refers to a resolution of 1920 × 1080 pixels, scanned progressively at a frame rate of 50 fps.

HE-AAC (High Efficiency Advanced Audio Codec)
HE-AAC is an extension of the AAC. HE-AAC is part of the MPEG-4-standard.

Hint Track
The hint track is one track of a MP4 file. It contains information needed by some streaming servers.

I

I-Frame
An I-frame is a single frame in a video clip that is compressed without making reference to any previous or subsequent frame in the sequence. This frame is compressed using techniques that are similar to still image compression techniques, such as those employed in the JPEG compression standard. For professional video editing systems that use compression as a means to extend hard disk capacities or required transmission bandwidth, so-called I-frame only video codecs are used. This way, a frame-accurate editing of a video clip is still possible. However, using I-frame only codecs for video compression is by all means a luxury as such a codec is inferior in compression efficiency as compared to a codec that uses B-frames or P-frames. For television systems, an I-frame is sent typically every half second in order to enable zapping. I-frames are the only frames in a video data stream that can be decoded by its own (i.e., without needing any other frames as reference).

IETF (Internet Engineering Task Force)
The Internet Engineering Task Force (IETF) is a large open international community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture and the smooth operation of the Internet. It developed the “Recommended Practices,” with the force or standards that determine how the Internet infrastructure operates. It is open to any interested individual. For more information, please visit www.ietf.org.

Interlacing
Interlacing is a classical technique for bandwidth reduction dating back to the time of analogue video and television. Interlacing works on the basis that only every second line of a video frame is shown during one time instant (i.e., alternating half images consisting either of the odd or the even lines of the image are shown alternatingly). The effect is that interlacing achieves a high temporal resolution (50 half images per second, or 56.94 half images per second) without requiring extra bandwidth. The high temporal resolution is beneficial for showing sports events or similar high motion events. On the other hand in relation to progressive scan the resolution of interlaced frames is perceived to be lower by the factor of 0.6.

ISMA
The Internet Streaming Media Alliance is a non-profit organization formed to create specifications that define an interoperable implementation for streaming rich media (video, audio, and associated data) over Internet Protocol (IP) networks. For further information, please visit www.isma.tv.

J

JPEG (Joint Photographic Experts Group)
JPEG is a lossy format that compresses images to significantly smaller file size retaining a high degree of color fidelity. It allows a user to choose to what degree an image should be compressed. The smaller, however, a file is compressed, the more colour information is lost.

K

Keyframe
A keyframe is the same as an I-frame.

L

Latency
Latency or delay is the time that data requires to transit from input to output.

M

Media
Audio, video, or image data can be classified as media.

Metadata
Metadata is additional information on multimedia content, e.g., the artist, format, copyright, compression methods, date, or any other asset descriptors deemed necessary by the content creator. There exist various formats to store and transmit meta-data along with the actual media content.

MHP (Multimedia Home Platform)
MHP is an open standard of the DVB project defining a generic interface between interactive digital applications and the terminals on which those applications are executed. It enables digital content providers to address all types of terminals ranging from low-end to high-end set top boxes, integrated digital TV sets and multimedia PCs.

MJPEG
MJPEG or motion JPEG is a non-interframe compression technique in which every video frame is compressed using the JPEG standard. The resulting movie is in essence a sequence of JPEG images.

Motion Compensation
Motion Compensation is the process of applying motion vectors to a reference picture to create a predictor. Motion vectors are usually generated during the process of Motion Estimation.

Motion Estimation
Motion Estimation is a technique used in video encoding which allows a high coding efficiency. Digital video frames consist of a high number of pixels which are classified as blocks. Instead of coding the original pixel values of each block as a whole, modern video coding standards (MPEG-1, 2, 4) allow to take advantage of redundant information and to only encode the difference of the original block to a predictor block. Differences appear for example because of movements or camera pannings. The prediction is based on a block in an earlier encoded picture which is called reference frame. By applying Motion Estimation, the prediction can be improved significantly. The input of a Motion Estimation is the original frame that should be encoded and a reference frame that is used for prediction. The output is a motion vector for each block in the frame. The applied motion vectors are also coded and become part of the resulting bit stream that finally represent a P- or B-frame.

MOV File
MOV is the quick time file format. Apple’s Quicktime player is required to view the content of this file (which can be audio and/or video). The MOV file format is the basis for the MP4 file format. For further information, please visit www.apple.com.

MP3
MP3 is a file format, in which audio has been compressed in accordance with the MPEG-1 standard (MPEG-1 Audio Layer 3) delivering CD quality audio. MP3 files can be downloaded via the Internet and played back on handheld devices (MP3 player) or on a PC.

MP4 File
The MP4 file format is the official MPEG-4 file format.

MPEG (Motion Pictures Experts Group)
MPEG, established in 1988, is a working group of ISO/IEC and has developed several standards for the coded representation of audio and video. MPEG has delivered standards such as MPEG-1 and MPEG-2 as well as, more recently MPEG-4, MPEG-7, and MPEG-21.
For more information, please visit www.chiariglione.org/mpeg.

MPG/MPEG File
MPG is the container file format containing MPEG-1 or MPEG-2 encoded video/audio (also for raw MPEG-1/ MPEG-2 video).

MPEG-1
MPEG-1 is a standard for video and audio compression developed by the Moving Picture Experts Group, which is mainly used for Video CD (VCD) playback.

MPEG-2
MPEG-2 is a standard for video and audio compression with several profiles developed by the Moving Picture Experts Group, which is mainly used for DVD playback and broadcast quality video (used in Digital TV).

MPEG-4
MPEG-4 is a standard for video and audio compression with several profiles developed by the Moving Picture Experts Group, which dramatically advances audio and video compression, enabling the distribution of content and services from low bandwidths to high-definition quality across broadcast, broadband, wireless, and packaged media. MPEG-4 also provides a standardized framework for many other forms of media—including text, pictures, animation, 2D objects, and 3D objects, which can be presented in interactive and personalized media experiences.

MPEG-4 Part 2
MPEG-4 Part 2 (Visual) is a video coding format which is based on H.263 but includes additional coding tools to achieve a higher coding efficiency than H.263 and MPEG-2. MPEG-4 part 2 offers numerous profiles. The most widespread are the Simple Profile (SP) and the Advanced Simple Profile (ASP). MPEG-4 part 2 has been used e.g. by DivX and also in 3GPP Rel. 5.

MPEG-4 Part 10
MPEG-4 Part 10 is synonym for both AVC (Advance Video Codec) and H.264. The denotation MPEG-4 Part 10 is used in the standard of the Joint Technical Committee of the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). MPEG-4 Part 10 offers numerous profiles. The most widespread are the Baseline (BP), Main (MP) and High Profile (HiP).

MPEGIF (MPEG Industry Forum)
The MPEG Industry Forum is a non-profit organization with the objective to further the adoption of MPEG standards by establishing them as well-accepted and widely-used standards among creators of content, developers, manufacturers, providers of services, and end users. See also www.mpegif.org.

Multicast Stream
A multicast stream is effectively a transmission from one point as the sender (broadcaster) to multiple viewers (i.e., it allows many recipients to share one source). Multicasting comes into play when large amounts of data need to be transmitted to a broad audience.

N

NTSC
USA video standard with 4:3 image format, 525 lines, and 60 Hz.

NVOD (Near Video on Demand)
NVOD makes it possible for a viewer to choose a particular content from a program selection and view same not instantly but within a few minutes after having made the selection.

O

On-Demand
On-Demand means that a viewer can view/access a selected program at any convenient time.

P

P-Frame
P-frames have their name from being predicted from a previous reference frame. That means for decoding a P-frame for a given time instant another previous reference frame at an earlier time instant is needed.
Even though P-frames are based on predictions coming from previous reference frames, a P-frame can again serve as a reference frame for predicting later P- or B-frames. P-frames are an effective video coding tool to improve coding efficiency as compared to a pure image encoder, which compresses each frame individually without making reference to any other frame. All coding schemes offering premium coding performance have a P-frame mechanism employed. However, using P-frames for coding requires the encoder and in the decoder to store the reference frame. For conversational applications, video encoders tend to us P- frames exclusively in order to avoid introducing extra delay, which is unacceptable. This holds for H.263 and its precursors as well as for MPEG-4 Simple Profile. A price to be paid for using P-frames is that frame exact editing in the coded bit stream is no longer possible. In order to reconstruct a P-frame the pertaining reference frame is needed. If either it is gone due to cutting the video material, the P-frame is gone as well. In MPEG, the reference frames for coding a P-frame can either be P-frames or I-frames.

Packet
In a data transmission between computers, data is transmitted in packets. These packets all contain relevant information including where this packet comes from and where it is supposed to go. Whilst the sending computer sliced up the data into packets, the recipient computer puts them back together.

PAL
European video standard with 4:3 image format, 625 lines, and 50 Hz.

PCM File
A PCM file stores raw uncompressed audio data.

Personal Video Recorder (PVR)
A PVR operates ostensibly like a DVR, but because it is orientated towards consumers, it may include more consumer specific functions, such as an electronic program guide, etc.

Profile
Profiles are a set of coding tools. Profiles are used for compatibility definition.

Progressive Download
A progressive download allows the viewer to watch or interact with the media while it is being downloaded at the same time.

Progressive Scan
Progressive scanning is a way of image formation that refreshes every line of a frame whereas interlaced scanning refreshes in the first step only odd and in the second step only even lines. Progressive scanning requires higher bandwidth but leads to a better picture quality. In relation to interlaced pictures the resolution of a progressively scanned picture is perceived to be better by the factor of 0.6.

Protocol
Data cannot just be transmitted as and how required. Since there are so many different hardware platforms and operating systems used by computers that need to be connected, data transmission must happen within a specific set of rules, which are called protocols. Examples for protocols are TCP/IP, PPP, RTP/RTSP, or FTP.

Q

QCIF
QCIF is a video resolution and a quarter of CIF. The size is 176 x 144 pixels.

Quarter pixel accuracy

Quarter pixel accuracy denotes a feature of MPEG-4 part 2 ASP or H.264 coders to compute virtual sub-pixels which are an interpolation of real pixels within a video frame. Thus broadening the base for the computation of P and B-frame motion vectors Quarter pixel accuracy raises the exactness of Motion Compensation and Motion Estimation.

Quantization
Quantization is the action of information reduction to get a higher compression result.

Quicktime (QT)
QuickTime is a technology by Apple Computers which adds digital video to the Macintosh platform. In 1992 Microsoft reacted on that technology by launching Video for Windows. Apple also makes QuickTime for Windows. QuickTime is also used to refer to the QuickTime Movie file format, a widely used format for digital audio, video, and other multimedia. See also www.quicktime.com.

QVGA (Quarter Video Graphics Array)
QVGA is a quarter of the resolution of a normal VGA computer display. QVGA has a resolution of 320 x 240 pixels.

R

Resolution
Resolution is the ratio of pixels used to display an image of a video and described in dots per inch (dpi). It relates to the clarity and detail of an image, and the higher the dpi, the clearer and precise the image.

RGB (Red, Green, Blue)
The colors are represented as red, green, and blue components. Most computer monitors use RGB pixels.

RTP/RTSP
RTP/RTSP are network protocols designed for real-time streaming over IP-networks. The RTP (Real-time transport protocol) provides the actual transport of the media and synchronization of audio and video. RTP is usually used with UDP/IP. The RTSP (Real-time streaming protocol) is mainly used for the session initialisation and control for unicast streaming. It usually uses TCP as underlying protocol layer.

S

SD (Standard Definition)
Standard definition refers to the resolution of video storage, transmission and viewing systems (e.g. NTSC, PAL, Secam). SD usually has a resolution of 480 (NTSC) or 576 (PAL) visible horizontal lines. SD is about to be replaced by HD (High Definition).

SDK (Software Developers Kit)
An SDK is a collection of software tools, API, and utilities which can be implemented by developers and programmers into their applications for specific platforms and usages.

SDP
The SDP is the session description protocol. It is typically used to initialize RTP/RTSP based streaming sessions.

Serial Digital Interface (SDI)
SDI is an industry-used abbreviation for the ITU R BT 601 standard, which describes the
SDI is an industry standard defined by SMPTE, which describes the interface of component digital video, which is used to connect video production equipment to transfer SD video.

Set-Top Box (STB)
A set-top box is an electronic device, which is used, in most instances, to receive and decode digital television broadcasts. In addition, they can also be used to access the Internet (instead of using a PC) and can further offer additional functions such as IP telephony, VOD, and other high-speed Internet TV services.

Society of Motion Picture and Television Engineers (SMPTE)
The Society of Motion Picture and Television Engineers is a professional membership organization that sets standards for the film and television industry. For more information, please visit www.smpte.org.

SP (Simple Profile)
The simple profile is a set of tools used for the video encoding in MPEG-4.

SQCIF
SQCIF (Sub Quarter CIF) is a video resolution which is less than a quarter of a CIF. The seize is 128 × 96 pixels.

Streaming
Streaming means the transmission of video and/or audio in packets from a server to a recipient. On the “other end,” these packets are put together again on arrival and can then immediately be played back even when not the complete piece of content has been transmitted. Continuously, packets are re-assembled into data, which is then played back. Streaming is not equal to a traditional download since all packets (i.e., the data) are discarded after playback. Timing is of the essence in streaming, which is why a protocol called RTP (real-time transport protocol) is utilized.

T

T1
T1 (trunk 1), also called DS1 (Digital Signal 1), originally is a telecommunication standard carrying 24 audio signals (at 64 kbps plus 8 kbps overhead) at a maximum data rate of 1.544 Mbps. Today commonly used in the broadcast industry T1 has become a synonym for any data circuit running at 1.544 Mbps. The standard is mainly used in North America, Japan and South Korea, whereas the rest of the world deploys E1.

T2, T3
Data circuits containg multiple T1 channels with a maximum bandwidth of 6.312 resp. 44.736 Mbps.

Transmission
Transmission is a term used for television style broadcasting but also used for the digital communication between computers over telephone lines or cable.

U

UDP (User Datagram Protocol)
UDP is a protocol to transmit data from a sender to a receiver. In contrast to TCP, UDP is a state-less protocol and does not guarantee any reliability. UDP can be used for unicast or multicast transmission.

Unicast
Unicast means that a data communication takes place between a single sender and a single recipient.

Unicast Stream
Unicast stream is an IP based point-to-point connection.

V

VBR (Variable bit rate)
In video coding, the bit rate of the encoded video stream varies over time. More complex parts of the video material lead to higher amounts of bits than do less complex parts. By allowing a variation of bit rates the perceived quality of more and less complex parts of the video stream can be kept constant.

VC1
VC1 is a coding standard by Microsoft. Used on HD-DVDs, blue-ray discs and Windows Media Videos. VC1 is comparable to MPEG-4 part 10 though not as powerful as MPEG-4.

VCD (Video CD)
Video CD is a standard for storing audio and video information on CD discs. A 74-minute video sequence can be stored on a single disc.

Video for Windows
A video/audio frame-work developed by Microsoft Corporation for encoding/decoding of video and audio data. For further information, please visit msdn.microsoft.com.

Video over IP
Video over IP is a method of transmitting video, audio, and data signals as packetized data over an IP network.

VOD (Video on Demand)
VOD is a service in which a viewer has full control of a selected program that was chosen for viewing. The program can be stopped, paused, fast forwarded, and rewound.

VOB File (Video Object File)
A VOB file is the data container mainly used on DVDs and can contain audio, video, text, etc.

Voice-over IP
Voice-over IP is in essence telephony via the Internet or networks based on Internet technology.

W

Webcast
A webcast uses the Internet to transmit live or delayed audio and/or video data to users; it can be compared with traditional TV and radio broadcast with the main difference being that the Internet is the transmission carrier.

WAN (Wide Area Network)
A WAN can be an assembly of smaller networks, for example even two LANs, whereas the geographical limit are not set as for a LAN (i.e., it can in theory even spread worldwide).

WLAN (Wireless Local Area Network)
A WLAN is in essence the same as a LAN, the network connection is not maintained via cable or fixed line connections but totally depends on wireless networking techniques.

X

XML (Extensible Markup Language)
XML is conceptually related to HTML, but it is in itself not a markup language. It is a language to create other specific languages and is used for the definition of specialized markup languages, which are used to transmit formatted data.

Y

YUV
YUV is the color space used in the PAL analog television standard.

YUY2
YUY2 is a color format very similar to YUV.