This glossary provides a brief description of VBrick products and defines technical terms used or referenced in the VBrick product documentation. This includes common terms and acronyms used in the streaming media industry. If you notice missing or incorrect terminology or want more information, send e-mail to
documentation@vbrick.com
VBrick's audio conferencing microphone. It connects to any VBrick encoder/decoder and provides full-room audio conference performance by automatically steering its dynamic audio pickup beam in the direction of the person speaking.
The Digital Signage application is used to create timed web pages that are displayed on a screen along with streaming video. These displays are used with a VBrick set top box and a VBStar to display "digital signage" along with the video stream on a TV monitor, a plasma screen, or other display device.
The ETV Portal Server manages the inventory of live, on-demand, and scheduled video assets. ETV Portal Server functions as a video portal, permitting end users to view live and on-demand MPEG-1, MPEG-2, MPEG-4 and WM streams on a PC, a Mac, or a Set-Top Box. It can be used to control all encoders/decoders, VOD servers, and set-top boxes in a network.
EtherneTV provides you a complete digital video solution to distribute video over your IP network. Distribute live broadcasts or existing content and view on any computer using standard video players such as Microsoft's Media Player or Apple's QuickTime.
VBrick's low-cost set-top box is an ideal MPEG decoder for cost sensitive installations that require large-scale deployment. The user-friendly set top box is controlled like a cable TV receiver through an IR remote. It can be used to access live streams, request stored content from EtherneTV-NXG Video On-Demand server or access the World Wide Web.
VBrick's NXG video-on-demand servers use a Linux-based operating systems on Dell hardware. Current supported devices include the NXG1 that supports up to 90Mbps of streaming capacity and the NXG2 that supports up to 250Mbps of streaming capacity.
Darwin Open Source server for Linux, Windows, Mac, etc. Ingests and plays MPEG-4 content only. Requires an FTP server. The Darwin server is the open source version of Apple's QuickTime Streaming Server and has the same code base as QuickTime.
VBrick's VOD-W video-on-demand servers use a Windows-based operating systems on Dell hardware. They ingest and stream unicast and multicast streams in the following formats: MPEG-1, MPEG-2, MPEG-4 RTSP unicast; MPEG-1, MPEG-2, MPEG-4 multicast.
VBrick's VOD-WM (Windows Media) video-on-demand servers use a Windows-based operating systems on Dell hardware. The VOD-WM server provides all standard video-on-demand features including support for Windows Media files.
Integrated Web Server. VBrick's appliance configuration application that uses a web interface. Used to configure and manage MPEG-2, MPEG-4, and WM devices over an IP connection.
VBrick uses industry standard FLEXlm software to manage MPEG-2 licensing for StreamPlayer. Whenever StreamPlayer with MPEG-2 Playback or StreamPlayer Plus starts an MPEG-2 stream, a license is checked out of a common pool.
VB1000-2000-3000 Series. VBrick's MPEG-1 network video appliances encode/decode NTSC or PAL video at TV quality and audio at CD quality. Configured with
VBAdministrator. This product has been superseded by Vbrick's MPEG4 and Windows Media VB4000-5000-6000 appliances.
VB4000-5000-6000 Series. VBrick's MPEG-2 network video appliances provide DVD quality video and CD quality audio at 1–15 Mbps of bandwidth. MPEG-2 is the world's most popular digital compression technology and is used to encode DVDs as well as Digital Cable and Digital Satellite broadcasts. Configured with
IWS.
VB4000-5000-6000 Series. VBrick's MPEG-4 encoders and decoders are versatile and reliable video appliances for one or two-way interactive communications over low or medium bandwidth IP networks. The VBrick MPEG-4 encoder/decoder can be used for webcasting, multicasting, transcoding, and two-way interactive video. Configured with
IWS. Designed for streaming over the Internet at lower bit rates (56K, 128K, 384K0 and over a LAN at higher rates (1Mbps and above).
The VBrick WM (Windows Media) Appliance converts analog video and audio from any source into digital Windows Media streams. It attaches to your network and delivers streaming video and audio to any Windows Media-compatible player or server. The VBrick WM Appliance can deliver the streams via multicast to any number of players on the network and it can serve the stream via unicast to up to 200 players or servers.
ES3/ES4. Additional SCSI storage arrays for the VBrick NXG2 VOD server. VBrick offers two versions of the ES storage array. These products are based on Dell’s PowerVault 220S storage system.
VBrick PC application used to view Live and On-Demand streams, including full play, pause, stop, fast forward, rewind, and seek capabilities. StreamPlayer can discover program names on a network by listening for a session announcement (
SAP) from VBrick devices. When you click a program name, StreamPlayer launches the stream in Windows Media Player. StreamPlayer Plus is an enhanced version that adds support for stream recording. StreamPlayer Plus is available for Windows, Linux, and Solaris and also includes a web deployment toolkit that lets you embed video in web pages.
VBrick kit for corporate vertical that consists of VBPresenter software, a VBrick WM Appliance, a Sony video camera, and the accessories, cables, and connectors you need to create multimedia VBPresenter presentations. See also
VBEduCast.
VBrick PC application used to discover VBrick devices on a network by listening for management session announcements (SAPs). When you click a device name, VBDirectory launches the IWS management application for that device. Also used to initiate an upgrade using VBDownload or VBAdministrator.
VBrick kit for education vertical that consists of VBPresenter software, a VBrick WM Appliance, a Sony video camera, and the accessories, cables, and connectors you need to create multimedia VBPresenter presentations. See also
VBCorpCast.
An external VBrick hardware device that uses the passthough port on an encoder to send control commands via an infrared link to third-party devices like VCRs, DVDs, etc. The VBIR can be programmed with codes representing IR command sets that are compatible with devices from many manufacturers.
VBrick PC application used to stream live multimedia presentations (including synchronized PowerPoint slide shows) using a VBrick WM (Windows Media) Appliance. It also works with VBrick's ETV Portal Server and VBrick's VOD servers or with a VBStar to deliver multimedia presentations over the public Internet or a private LAN.
VBrick's software development kit lets end users write custom applications to control VBrick appliances. The SDK includes the VB1000-2000-3000 SDK for MPEG-1 devices; the VB4000-5000-6000 SDK for MPEG-2, MPEG-4, and WM devices, and the ETV-STB-SDK for EtherneTV Set Top Boxes.
Streaming Distribution System. A customized VBrick product solution that includes all streaming media components in one movable cabinet. It may include encoders/decoders, VCRs, DVDs, and all associated cabling and control software configured in "slices."
Security, Surveillance, and Monitoring. The VBSSM-MP2 and VBSSM-MP4 are MPEG video‑only encoders for security and surveillance monitoring applications where full motion, high-quality video is required. The VBSSM is a compact, ruggedized device that supports temperature ranges from -20 to 70°C.
These MPEG-2 VB4000-50000-6000 Series encoder/decoders include all of the basic features of the MPEG-2 appliances and add the capability of recording incoming streams for store and forward use on an included 60GB hard drive.
Video-on-demand. Generic acronym for any streaming video server that can store and serve video streams when requested by end users. Vbrick currently uses NXG (Unix), VOD-W (Windows), VOD-WM (Windows Media), and VOD-D (Darwin) VOD servers.
Realtime VB6000 Series MPEG-4 encoder. Designed for low or medium bandwidth IP networks. Supports unicast and multicast streaming at 8 kbps–2Mbps. VBXcast is a video server that can receive RTSP requests and deliver up to 120 individual streams to multiple viewers (not exceeding 38 Mbps total). Designed to provide low speed video streams that can be decoded by different players.
An electrical signal that has a continuous nature rather than pulsed or discrete. An example is the traditional format in which multiplexed video and audio are transmitted using an RF carrier, modulated by changes in amplitude and phase induced by video and audio signals. See
digital.
Asymmetrical Digital Subscriber Line. A traditional two-wire telephone line which for both high-speed digital computers and conventional analog telephone service. Called asymmetrical because the data transmission rate is higher in one direction than the other.
Refers to two or more electrical signals having the same average nominal rates but de-synchronized with respect to one another. The term asynchronous is also often used in telecommunications to refer to serial 1 bit wide transmissions used between computer systems. See
synchronous.
A communication layer within the ATM protocol. The ATM layer is the adaptation layer or AAL. AAL layers start a 0 and transgress to 5. AAL0 actually means no AAL layer and AAL 5 is the highest layer which can accommodate very large packet sizes.
Short for bi-directional frame. A video compression method used by the MPEG standard. In a motion sequence, individual frames of pictures are grouped together (see
GOP) and played back so that the viewer registers the video’s spatial motion.
(1) A range of frequencies between two defined limits expressed in cycles per second, or hertz (Hz). It is also the information carrying capacity of a circuit. (2) The expression of the carrying capacity of the transmission line. In a digital transmission, the bandwidth is the range of transmission rates at which information can be sent in a particular medium. The bandwidth is expressed in kilobits per seconds or megabits per second (Mbps). (3) The capacity of a transmission channel.
A unit of transmission speed equal to the number of times the state (or condition) of a line changes per second. The baud rate usually refers to the number of bits transmitted per second (BPS).
Some VBrick VB6000 Series models have built-in mini-browsers that support viewing of limited HTML pages. The billboard feature lets you display text and/or graphics on a monitor. The HTML pages are saved in the VBrick or can be located on a remote HTTP server.
The number of bits transferred per unit of time, typically expressed in bits per second. For example, a file compressed to 28.8Kbps contains 28.8 kilobits of data for each second. Similarly, a 28.8Kbps modem can transfer a maximum of 28.8 kilobits of data per second.
An area where frequently used information is kept readily available. A cache improves performance by reducing delay caused from unnecessary and redundant data transfer. A computer browser speeds page retrieval by storing local copies of recently viewed pages.
Constant bit rate. A characteristic of a data stream in which the bit rate remains nearly uniform for the duration of the stream. CBR traffic requires guaranteed levels of service and throughput.
Compact disk. An optical storage medium for digital data. CD-R is compact disk-recordable—a type of CD on which files can be copied, but not erased or replaced. CD-RW is compact disk-rewritable—a type of CD on which files can be copied, erased, and replaced.
Common Interface Format or Common Image Format. The Common Interface Format was developed to support video conferencing. It has an active resolution of 352 x 288 and a refresh rate of 29.97 frames per second. See also
SIF,
resolution.
In audio, an audible distortion that occurs because an input or output level exceeds the equipment's dynamic range. The term clipping is analogous to the "cutting-off" of the highest excursions of the audio signals.
Text information added to the video signal. It can be descriptive text (sub-titles or information for the hearing impaired) and/or the words being spoken in the program. The data for the captions are included in the video signal but outside the active video image. They are placed on line 21 of the vertical blanking internal. It is called closed because it is not seen unless it is called up by the receiving device.
Encoder/decoder. A process or device by which or in which a signal is encoded for transmission or storage then decoded for playback. As a process it is the algorithm that handles the compression and decompression of video or audio files. As a device it a VBrick appliance that accomplishes the encode/decode process.
Reduces the amount of bandwidth need to transmit a digital file or a live stream. lossless compression describes a technique that compresses the original signal in exact form;
lossy compression discards unnecessary content prior to compression. Lossy compression is commonly used for video.
Refers to the control used to set the peak white level of the picture or the ability of the set to show a large difference between black level and white level. A high contrast picture will appear to have more detail.
Three colors—red, blue, and green—are used in television to produce all colors. These separate scanning beams (one for each color) must strike their targeted phosphors (screen's internal coating) with precise accuracy. If the beams are out of alignment, the image and colors are muddied.
In TCP/IP, the basic unit of information passed across the Internet is called an IP datagram. It consists of a complete unit of information containing source and destination IP addresses along with protocol-specific information and user data.
Data Communications Equipment. A device that establishes, maintains and terminates a session on a network. It may also convert signals for transmission. It is typically the modem.
To decode compressed audio and video content to a specified digital format. A decoder converts live or prerecorded audio and video content that was compressed during encoding. VBrick supports MPEG-1, MPEG-2, and MPEG-4, decoders.
Dynamic Host Configuration Protocol. Allows administrators to centrally manage and automate the assignment of IP addresses in a network. DHCP lets a network administrator supervise and distribute IP addresses from a central point and automatically sends a new IP address when a computer is plugged into a different place in the network.
The transmission of discontinuous electrical signals containing information encoded in binary form that has only two possible states: 0 or 1. Digital signals have the distinct advantage over analog because they are easily transported and replicated without loss to the original. See also
analog.
Domain Name System. The name resolution system that lets users locate computers on a Unix network or the Internet (TCP/IP network) by domain name. The DNS server maintains a database of domain names (host names) and their corresponding IP addresses.
Digital rights management. A technology that provides a persistent level of protection to digital content by encrypting it with a cryptographic key. Authorized recipients (or end users) must acquire a license in order to unlock and consume the content.
To convert audio and video content to a specified digital format. An encoder converts live or prerecorded audio and video content to a specified digital format. Typically, content is compressed during encoding. VBrick supports MPEG-1, MPEG-2, MPEG-4, and WM encoders.
Recovers data lost from transmission dropouts or packet loss. Error correction requires additional overhead in the transmitted data stream. In Windows Media Player, error correction ensures that digital data is read accurately during playback or copying.
A baseband LAN specification invented by Xerox Corporation and developed jointly by Xerox, Intel, and Digital Equipment Corporation. Ethernet networks operate at 10Mbps using CSMA/CD to run over coaxial cable. Ethernet is similar to a series of standards produced by IEEE referred to as IEEE 802.3.
Repeated rapid increase and decrease of pitch of the reproduced audio, more than about two repetitions per second, due to non-uniform linear speed of analog tape. Also choppy rapid breakup and resynchronizing of a television picture from any cause.
The ability to transmit and receive data simultaneously. For ethernet LAN connections, this implies the presence of media and ethernet controller hardware that is capable of transmitting and receiving at the same time on both ends of the connection. See
half-duplex.
A router (or any computer) that performs protocol conversion between different types of networks or applications. For example, a gateway can convert a TCP/IP packet to a NetWare IPX packet and vice versa. Gateways perform complete conversions from one protocol to another rather than simply supporting one protocol from within another, such as IP tunneling.
Group of Pictures. The collection of I, B, and P frames comprises a Group of Pictures. The selection of GOP parameters is a trade-off between bandwidth, quality, sensitivity to transmission error, and delay. An extended GOP will be more sensitive to transmission errors.
High Definition Compatible Digital. A patented encode/decode process that improves the quality of all forms of digital audio recording and playback by increasing resolution and reducing distortion that occurs during analog-to-digital (A/D) and digital-to-analog (D/A) conversion, digital processing, and digital filtering.
Hyper Text Markup Language. The language used in the World Wide Web to create web pages with links to other documents, rich text enhancements (bold, italic, etc.) and so on. The "source" file for what you see on a web page is written in HTML.
A forwarding technique that allows a stream to effectively bypass a firewall protecting a LAN. A streaming server is configured to send data to the intended destination client over HTTP (port 80); the client sends responses back to the server in the same manner.
A "single color" disregarding brightness or luminance. The simplest way to describe hue is to say that pink and red are of the same hue and azure, blue, and navy are of the same hue. Hue control is the same as tint control.
A video frame that is encoded without reference to other frames (see P-frame and
B-frame) and which encode differences between the current frame and a previous frame or future frame. An I frame must be decoded before video can be displayed.
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.
The Internet Control Message Protocol defined by the IETF (Internet Engineering Task Force) document RFC 792. ICMP messages are layered over IP and are used to implement "ping" (or ICMP echo) and to report various IP communication errors.
The process of adding content to a VOD server. This process adds the content to the VOD server's database and includes analysis of the content to allow fast forward and rewind. See also
trick control.
Also called an Internet address. This is a 32 bit address assigned to hosts on an IP network. The address is written in dotted decimal format as four eight-bit numbers (or octets) separated with periods.
Integrated Services Digital Network. The recommendation published by CCITT for private or public digital telephone networks where binary data, such as graphics and digitized voice and data transmission, pass over the same digital network that carries most telephone transmissions today.
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.
Also called an Internet address. It is a 32-bit address assigned to hosts using TCP/IP. The address is written as four octets separated with periods (dotted decimal format) that are made up of a network section, an optional subnet section, and a host section.
Internet Streaming Media Alliance. A group of industry leaders (including VBrick) whose goal is to accelerate the adoption and deployment of open standards for streaming rich media content such as video, audio, and associated data over Internet protocols.
Joint Photographic Experts Group (JPEG) Industry organization developing standards and specifications for the encoding of photographic images over various media and network technologies.
Lightweight Directory Access Protocol. A protocol used to access a directory listing. LDAP support is being implemented in Web browsers and e-mail programs which can query an LDAP-compliant directory. Supported in
EtherneTV Portal Server for authentication and authorization.
A Windows Media file that has an associated license that defines how the file can be played. The restrictions stated in the license vary depending on the license creator. When a CD track is copied by using Windows Media Player, a license can be assigned to the newly created file. Under that license, the file can only be played on the computer where the file was created.
Video circumstances where picture and sound are not synchronized in time. Lip movement that does not match the words spoken. Video processing units like line doublers that accumulate several frames of video can introduce lip sync error.
Relieving a resource constraint by distributing processing or traffic across multiple devices. For instance, serving video content from multiple VOD servers or sending network traffic across multiple network paths.
A process for compressing data in which information is removed and cannot be recovered upon decompression. Typically used with audio and visual data in which a slight degradation of quality is acceptable.
Brightness of a light emitting object, or the portion of a video signal that represents brightness. Used by itself, the luminance signal is sufficient to produce a full black and white image.
A Media Access Control (MAC) address is a hard-coded interface identification used by layer 2 devices (switch or bridge) for proper forwarding of frames between computers on a network. MAC addresses are usually represented as a group of 6 hexadecimal numbers as in the following example: 00:50:c2:00:c5:35.
Management Information Base. A database of information on managed objects that can be accessed via network management protocols such as SNMP and CMIP. MIB object can be accessed and managed using the
VBSDK.
Data about data. Information about digital media content such as the artist, title, album, producer, and so on. VBrick encoders allow insertion of real-time metadata strings into the video stream and decoders can receive and act on the real-time metadata to trigger operations such as URL flips.
Musical Instrument Digital Interface. A specification of the MIDI Manufacturers Association (MMA). The specification defines a protocol for describing music data, such as note on and note off messages; a file format for storing music data, called Standard MIDI; and a standard hardware interface.
Moving Picture Experts Group. The committee that creates international standards for coding audio-visual information to a digital, compressed format. The acronym MPEG is appended to the beginning of individual specifications developed by the committee. For example, MPEG-2 refers to the standard, ISO/IEC - 11172.
Communication between a single sender and multiple receivers on a network. Useful for content delivery where a single stream is transmitted to multiple clients not connected to the server. The server sends one copy of the stream to multicast-enabled routers which replicate the data. Clients receive the stream by monitoring a specific multicast IP address and port. See
unicast.
An IP address that uniquely identifies a multicast stream of packets on a network. Same as group address. A multicast sender sends packets to such an address and a multicast receiver receives packets from such an address. Multicast addresses (also called Class D addresses) are in the range 224.0.0.0 to 239.255.255.255.
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.
National Television System Committee. In the United States, a television industry group that develops standards for television broadcasting and receiving equipment. Used in the U.S., Canada, and Japan. See
PAL.
Predictive (or predicted) frame. A video compression method used by the MPEG standard. In a motion sequence, individual frames of pictures are grouped together (see
GOP) and played back so that the viewer registers the spatial motion. A P-frame follows an
I-frame and contains only the data that has changed from the preceding I-frame (e.g. color or content).
Continuous sequence of binary digits of information is switched through the network and an integral unit. Consists of up to 1024 bits (128 octets) of customer data plus additional transmission and error control information.
A network in which data is transmitted in units called packets. The packets can be routed individually over the best available network connection and reassembled to form a complete message at the destination.
Serial port passthrough lets users control remote devices like cameras, DVDs, or VCRs that are connected to the serial port on an appliance. VBricks have up to two serial ports that can be used for passthrough and each operates at its configured baud rate (e.g. 115.2–300K bps). Some common applications include remote control of a camera (pan-tilt-zoom), remote control of security doors, low speed data transport, or data collaboration between PCs.
Protocol Data Unit. The technical name of a frame of data transmitted over the data link layer in a communications network such as Ethernet or Token Ring. Many people simply call every unit of data travelling over a network a "packet."
Picture in Picture. A small video image is superimposed on a specified area of the monitor to allow the user to see two independent videos on a single monitor. VBrick encoder/decoder models use PIP (configurable in
IWS) to show an image of the encoder's video along with the decoder's video. PIP is often used in two-way video applications to allow the local user to monitor the video being sent along with the video being received.
Picture element. The smallest spot on a video display device that can be resolved as having a different brightness or color from what is next to it. The complete video image is a rectangular array of pixels.
A checkerboard-like coarse grainy effect over portions of a picture due to inability of the processing of digital video to keep up with subject motion and other frame to frame changes. Sometime used to mask or censor part of the picture content.
A mobile electronic device that can exchange files or other data with a computer or device. Examples of portable devices include Pocket PCs, portable digital music players, and Smartphones.
A dynamically generated list of all video streams currently available on the network, often based on the receipt of a VBrick
SAP. You typically navigate a VBrick decoder or
set top box program guide using an IR remote control to choose a program. You typically navigate the StreamPlayer or MCS Portal Server program guide by clicking on a program entry.
A server located on a network between client software, such as a web browser, and another server. It intercepts all requests to the server to determine whether it can fulfill them itself. If not, it forwards the request to another server.
Clients access content streams from a Microsoft Windows Media server by connecting to a publishing point. Windows Media Services includes two types of publishing points: on-demand and broadcast. Either type can be configured to deliver a stream from one of several types of sources, such as a live stream from a VBrick WM Appliance, a file, or a playlist. One Windows Media server can be configured to run multiple publishing points, hosting a combination of broadcast and on-demand content.
The clarity or sharpness of the picture. Also the size of a video frame, measured in pixels. Analog resolution standards generally refer to lines of horizontal resolution as shown below. See also
CIF,
SIF.
Real Time Streaming Protocol. An internet specification for streaming media. RTSP can control multiple data delivery sessions, provide a means for choosing delivery channels such as
UDP, multicast UDP and TCP and provide a means for choosing delivery mechanisms based upon RTP.
Super video. A video signal transmitted as two subsignals requiring two separate wires: luminance (Y) and color (C). S-video can represent standard definition interlaced video signals only. The S-video cable plug has separate pins for color and luminance.
The process of converting an analog entity to digital form. In the case of a picture, a large number of evenly spaced spots (samples) are taken and each represented as one or more numbers for brightness (luminance) and color. These spots are referred to as picture elements or pixels. The more samples are taken, the more accurate (with higher resolution) an image can be reconstructed from the samples. See
RAID.
Session Announcement Protocol. VBrick uses SAPs to announce the presence of a device on the network. If configured, each VBrick periodically multicasts a SAP announcement to the network which can be detected by listeners. For example, StreamPlayer listens for program SAPs and can launch a stream; VBDirectory listens for management SAPs and can be used to configure or update a device.
Small Computer System Interface. SCSI is a hardware interface that allows for the connection of up to 15 peripheral devices to a single PCI board called a "SCSI host adapter" that plugs into the motherboard.
Standard (or Source) Input Format. This video format was developed to allow the storage and transmission of digital video. The 625/50 SIF format has a resolution of 352 x 288 active pixels and a refresh rate of 25 frames per second. The 525/60 SIF format has a resolution of 352 x 240 active pixels and a refresh rate of 30 frames per second. The computer industry, which uses square pixels, has defined SIF to be 320 x 240 active pixels, with a refresh rate of whatever the computer is capable of supporting. See also
CIF,
resolution.
Simple Network Management Protocol. The Internet network management protocol. SNMP provides a means to monitor and set network configuration and runtime parameters. SNMP can be used to control VBrick appliances.
A method of delivering digital media across a network in a continuous flow over networks and the Internet. The digital media is played by client software as it is received. Streaming files match the encoded bit rate to the connection speed of the user so the remote viewer can play audio or video with minimal stoppage without first downloading the entire video file.
Used to group IP addresses together. Routers use a subnet mask to define the group (or IP subnet) to which an
IP address belongs so that it can identify the correct interface from which it should forward an IP packet.
Super VGA. A computer video signal format with 800 pixels horizontally and 600 pixels vertically. This format was originally defined based on a video memory size of half a megabyte for 256 colors, or one 8 bit byte per pixel.
Secure Shell. Proprietary software that provides secure logon for Windows and Unix clients and servers. SSH replaces telnet, ftp and other remote logon utilities with an encrypted alternative.
In Windows Media Player, the process of maintaining digital media files on a portable device based on the rules in a partnership or actions specified by the user. This may require copying digital media files from a computer to a device, updating information on the device, or deleting files from the device.
Digital transmission facility operating with a nominal bandwidth of 1.544Mbps. Also known as Digital Signal Level 1 (D1). Composed of 24 DS-0 channels in many cases. The T1 digital transmission system is the primary digital communication system in North America.
Transmission Control Protocol/Internet Protocol. The common name for the suite of protocols developed by the U.S. Department of Defense in the 1970s to support the construction of world-wide inter-networks. TCP and IP are the two best-known protocols in the suite. TCP corresponds to Layer four (the transport layer) of the OSI reference model—it provides reliable transmission of data. IP corresponds to layer three (the network layer) of the OSI reference model—it provides connectionless datagram service.
Television from Cinema. Machine used to transcribe movie film content onto electronic media. The most common mechanism in professional equipment does not use a video camera but instead has a "one pixel" sensor that scans across an illuminated film frame however many lines (480 for NTSC) are needed. Such a mechanism is called a flying spot scanner.
A small representation of a page or image. Thumbnails provide a convenient way to browse through multiple images before retrieving the one you need. Programs often let you click on the thumbnail to retrieve it.
On a DVD, typically, the largest unit of content, such as a movie or TV program, is called a title. There is not a consistent standard across all DVDs and because of this, a DVD can contain one or more titles.
Transmission Control Protocol. The protocol within TCP/IP that governs the breakup of data messages into packets to be sent via IP, and the reassembly and verification of the complete messages from packets received by IP.
A (Windows) Internet utility that describes the path in realtime from the client machine to the remote host being contacted and reports the IP addresses of all the routers in between.
IWS provides a traceroute utility to test VBrick devices.
Generally an individual song or other discrete piece of audio content. Also a distinct element of audio visual information, such as the picture, a sound track for a specific language, etc.
To test for a particular condition in a running program. An error trap tests for an error condition and provides a recovery routine. A debugging trap waits for the execution of a particular instruction in order to stop the program and analyze the status of the system at that moment.
User Datagram Protocol. 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. UDP is present on top of IP at the same level as TCP.
Uniform Resource Locator. An identifier which describes the location of a particular piece of information ("document") including the protocol used to retrieve that information. For example, http://www. interop.com/publications/connexions.html says: Use the HTTP protocol to retrieve the file "connexions.html" from host "www.interop.com" in directory "publications."
Variable bit rate. A characteristic of a data stream in which the bit rate fluctuates depending upon the complexity of the data. Suitable for applications that produce traffic of varying bit rates, like common LAN applications, which produce varying throughput rates.
The process of automatically increasing or decreasing the volume during playback to make all audio content sound similar with respect to volume levels. Volume leveling may change the original dynamic range of the content.
Virtual Private Network. A network service offered by public carriers in which the customer is provided a network that in many ways appears as if it is a private network (customer-unique addressing, network management capabilities, dynamic reconfiguration, etc.) but which is actually provided over the carrier's public network facilities.
