ACQUISITION RESOLUTION - This is the size of the image, expressed in pixels, which results from the acquisition of a video stream. The PAL and SECAM standards correspond to a resolution of 768 x 576 pixels, i.e. the full screen on a television set. The NTSC standard is less efficient, with a resolution of 720 x 480. PAL (Phase Alternate Line) is a video format used in Europe by professionals (and the public at large in numerous countries). NTSC (National Television System Committee) is the video norm used in the USA and Japan. With 30 images/second instead of 25, it needs decoding in order to be viewed on European equipment. NTSC coding is less efficient than PAL or SECAM.
ANALOGUE - Transmission standard for signals via a network, e.g. for telephone lines, as opposed to digital. Representation of a physical phenomenon with the aid of a signal in a form equivalent to continuous variation, in contrast to the discontinuous variations of a digital signal. To summarise, analogue, the form of wave created, is materialised by an electrical signal in a form equivalent to continuous variation.
ATSC (Advanced Television Systems Committee) - International organisation (140 members) established in 1982 to develop digital television standards. The United States adopted the ATSC-DTV standards in 1996, followed by Canada, South Korea (1997), Taiwan, Argentina (1998) and Mexico (2004).
BANDWIDTH - One of the characteristics of the devices that process or transmit signals. The bandwidth is the range of frequencies that the device can transmit without weakening the signal. The width of the bandwidth is generally expressed in kilohertz (KHz) or megahertz (MHz). The bandwidth in television is 5.5 MHz. Within the context of media digitization, the bandwidth is increasingly expressed in terms of the quantity of digital data transferred per second, typically in Mb/s. The digital television networks via satellite generally send an MPEG-2 signal of 4-6 Mb/s, while the bandwidth in the professional EVS equipment is 50-100 Mb/s. A particularly important characteristic in the audiovisual chain, the bandwidth is the quality gauge for its global performance. It expresses the capacity of a channel to transmit a stream of information.
BROADCAST, BROADCASTING - Broadcast, televise, transmit, televised programme. By extension, this term designates the television industry. Broadcasters are all the companies in charge of producing and broadcasting programmes.
CHANNEL - In a server, an independent way of managing a video (or audio) signal. It could be a record or playback channel. The LSMXT[2]® server can have up to 6 channels.
CODEC - Equipment or software which translates analogue sounds or recorded videos into digital data. For the transmission of this information to take up the least possible bandwidth, codec also performs the function of data compression, without altering the original signal, of course.
CONVERGENCE - Digitization brings the worlds of telecommunications, media and information technologies closer together. The different types of networks (cable, hertzian, computer terminals, television) will be used to transport and process information and services (image, sound, computer data). Terms of Reference for Electronic Communications Committee, CEPT, European agreements of Bergen, 21 September 2001.
DIGITAL - Method of coding in a binary system (basis 2) enabling the transformation and compression of images and sound into computer data (thanks to the coding of information in the form of series of “0” and “1” in a very precise order), which provides for better transmission. The image is sharper and the sound has a laser quality.
DIGITAL COMPRESSION - This is a method that makes it possible to reduce the space taken up by a digital file while protecting all the information contained in it. This enables satellite retransmission capacities to be multiplied by 8 to 10 times while reducing the volume of the information transmitted. It is digital compression that enables the carrying of close to 10 networks on one channel which received only one beforehand. In contrast, decompression is the transition of binary data to audio and/or video signals.
DIGITIZATION - Conversion of analogue signals into digital signals (“0” or “1”, binary language) in order to memorise, process or transmit them. The signal is coded in the form of numbered values, generally binary, with the aid of a converter.
DIGITAL TELEVISION - Type of television where the signals are processed in digital form throughout the image chain, from the camera sensor to the TV viewer’s receiver: production, transmission, broadcasting, reception and storage are digital.
EDITING - Production stage in cinema, television and video in the course of which the filmed or recorded material is viewed, divided into parts and sequences, cut and recomposed to form the final version. The compiling of these shot images results in the production of a film or television programme. Editing can be linear, where the sequences follow each other chronologically on the magnetic carrier, or non-linear, where the sequences are directly accessible on the digital carrier.
HIGH DEFINITION (HD) - New broadcasting TV format which significantly increases picture quality. HD images offer a higher amount of pixels per image (about 2 millions) than the traditional image in standard definition (about 400,000).
INTERACTIVE TELEVISION - This is a term generally used to describe enhanced television (interactive content provided by specific TV programmes), interactive programme guides (IPG), video tape recorders (PVR) and walled gardens (“jardins murés” - closed interactive services).
JPEG (Joint Photographic Expert Group) - Group of experts responsible for developing a compression format for natural images. It is the name given to an algorithm used for the compression of digital images. Compression is carried out by applying a single tone to colours that are very close. This limits losses in the resolution of the graphic image. The method is mainly used for the production of programmes.
LSM (Live Slow Motion) - Trade name of the EVS recorders dedicated to production and replay.
MPEG (Moving Picture Experts Group) - Group of experts responsible for developing a video compression format (animated and audio images). The special feature of the current standards, MPEG-2 and MPEG-4, is that they cover all multimedia applications (telecommunications, audio, still and animated images, interactive applications) and associated carriers (magnetic tapes, compact disks, computers, televisions). The MPEG-2 standard, designed for digital television and adopted in 1994, reduces the size of the image files in the ratio of 1/15 to 1/40. It, too, covers all multimedia applications (telecommunications, audio, still and animated images, interactive applications) and associated carriers (magnetic tapes, compact disks, computers, televisions).
MPEG (Moving Picture Experts Group) COMPRESSION - The MPEG standards are designed to compress audio and video data with a view to transporting them on networks and multimedia supports. MPEG-1 was created for VCD and CD-i, MPEG-2 for DVD. The outstanding feature of MP3 is that it stems from a development of MPEG-1, i.e. the MPEG-1 audio layer 3. The latest development is MPEG-4, designed for audio and video, as well as images created by computer (2D and universal 3D), and enables content to be adapted to specific terminals or networks (mobile telephone via satellite).
MXF (Material EXchange Format) - A file format from the Pro-MPEG Forum for the interchange of video production information. MXF files include audio/video content and related metadata.
OUTSIDE BROADCAST (OB) - Pooling of each programme transmitted or recorded outside a studio complex, mainly from “production cars“ or “OB vans“ equipped with cables, monitors and servers.
PLAY-LIST - List of video data which will be broadcast (pictures, prerecorded programmes, live, etc.).
SERVER - This is a computer used for the management of a network. Correspondingly, in television, it is a hard disk recorder on which pictures are stored for broadcasting to viewers or to operators within the TV channel.
STREAMING - Technique making it possible to download and simultaneously listen to an audio or video file. Its applications are numerous, from the broadcasting of an extract to live video transmission via the internet (remote, concert, live, etc.). Streaming enables your visitors to hear or view your content almost instantaneously without having to wait for the file to be transferred in its entirety: the sound starts just a few seconds after commencement of downloading.
TRANSMISSION - Operation of transmitting programmes to television viewers using terrestrial, cable or satellite broadcasting. Transmission may be analogue if the data transmitted is analogue, or digital if the data transmitted is digital.
VIDEO COMPRESSION - Compression of image sequences. The video compression algorithms take advantage of the fact that there are only a few changes during the transition of an “image” to a text. They therefore only need to code the initial image and the sequence of differences between the images. This is what is known as inter-image or 3D coding.
VIDEO TAPE RECORDER (VTR) - Equipment for recording video on magnetic tapes (video tape recorder) which can be connected to a computer to serve as a protection device.
WATERMARKING or FORENSIC MARKING - Information is placed into an image (still or moving) in such a way that it should be invisible and able to withstand any modification of the image (transcoding, bit rate reduction, cropping, etc.). This forensic information could be extracted from the images after piracy (camcorded images in a theatre room for example) and should make it possible to locate the origin of the piracy.