Video Server
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{{refimprove, date=September 2014 A video server is a computer-based device that is dedicated to delivering video. Video servers are used in a number of applications, and often have additional functions and capabilities that address the needs of particular applications. For example, video servers used in security, surveillance and inspection applications typically are designed to capture video from one or more cameras and deliver the video via a computer network. In video production and broadcast applications, a video server may have the ability to record and play recorded video, and to deliver many video streams simultaneously.


Video broadcast and production

In TV
broadcast Broadcasting is the distribution of audio or video content to a dispersed audience via any electronic mass communications medium, but typically one using the electromagnetic spectrum ( radio waves), in a one-to-many model. Broadcasting began ...
industries, a server is a device used to store broadcast quality images and allows several users to edit stories using the images they contain simultaneously. The video server can be used in a number of contexts, some of which include: * News: providing short news video clips as part of a news broadcast as seen on networks (like
CNN CNN (Cable News Network) is a multinational cable news channel headquartered in Atlanta, Georgia, U.S. Founded in 1980 by American media proprietor Ted Turner and Reese Schonfeld as a 24-hour cable news channel, and presently owned by ...
and
Fox News The Fox News Channel, abbreviated FNC, commonly known as Fox News, and stylized in all caps, is an American multinational conservative cable news television channel based in New York City. It is owned by Fox News Media, which itself is owne ...
). * Production: enhance live events with
instant replays Instant replay or action replay is a video reproduction of something that recently occurred which was both shot and broadcast live. The video, having already been shown live, is replayed in order for viewers to see again and analyze what had ju ...
and
slow motion Slow motion (commonly abbreviated as slo-mo or slow-mo) is an effect in film-making whereby time appears to be slowed down. It was invented by the Austrian priest August Musger in the early 20th century. This can be accomplished through the use o ...
and highlights (sport production) (see OB Vans) * Instruction: delivering course material in video format. * Public Access: delivering city specific information to residents over a cable system. * Surveillance: deliver real-time video images of protected site. * Entertainment: deliver anything used for entertainment. It can be gaming, news, movie trailers, or movies. A professional-grade video server performs recording, storage, and
playout In broadcasting, channel playout is the generation of the source signal of a radio or television channel produced by a broadcaster, coupled with the transmission of this signal for primary distribution or direct-to-audience distribution via any ...
of multiple video streams without any degradation of the video signal.
Broadcast quality Broadcast quality is a term stemming from quad videotape to denote the quality achieved by professional video cameras and time base correctors (TBC) used for broadcast television, usually in standard definition. As the standards for commercial tele ...
video servers often store hundreds of hours of compressed audio and video (in different
codecs A codec is a device or computer program that encodes or decodes a data stream or signal. ''Codec'' is a portmanteau of coder/decoder. In electronic communications, an endec is a device that acts as both an encoder and a decoder on a signal or d ...
), play out multiple and synchronised simultaneous streams of video by, and offer quality interfaces such as SDI for digital video and XLR for balanced analog audio,
AES/EBU AES3 is a standard for the exchange of digital audio signals between professional audio devices. An AES3 signal can carry two channels of pulse-code-modulated digital audio over several transmission media including balanced lines, unbalanced l ...
digital audio and also
Time Code A timecode (alternatively, time code) is a sequence of numeric codes generated at regular intervals by a timing synchronization system. Timecode is used in video production, show control and other applications which require temporal coordinatio ...
. A
genlock Genlock (generator locking) is a common technique where the video output of one source (or a specific reference signal from a signal generator) is used to synchronize other picture sources together. The aim in video applications is to ensure the ...
input is usually provided to provide a means of synchronizing with the house reference clock, thereby avoiding the need for
timebase correction Time base correction (TBC) is a technique to reduce or eliminate errors caused by mechanical instability present in analog recordings on mechanical media. Without time base correction, a signal from a videotape recorder (VTR) or videocassette ...
or frame synchronizers. Video servers usually offer some type of control interface allowing them to be driven by broadcast automation systems that incorporate sophisticated
broadcast programming Broadcast programming is the practice of organizing or ordering (scheduling) of broadcast media shows, typically radio and television, in a daily, weekly, monthly, quarterly or season-long schedule. Modern broadcasters use broadcast automatio ...
applications. Popular protocols include
VDCP Video Disk Control Protocol (VDCP) is a proprietary communications protocol primarily used in broadcast automation to control hard disk video servers for broadcast television. VDCP was originally developed by Louth Automation and is commonly called ...
and the
9-Pin Protocol The Sony 9-Pin Protocol or P1 protocol is a two-way communications protocol to control advanced video recorders. Sony introduced this protocol to control reel-to-reel type C video tape recorders (VTR) as well as videocassette recorders (VCR). It ...
. They can optionally allow
direct to disk recording A hard disk recorder (HDR) is a system that uses a high-capacity hard disk to record digital audio or digital video. Hard disk recording systems represent an alternative to reel-to-reel audio tape recording and video tape recorders, and provid ...
using the same
codec A codec is a device or computer program that encodes or decodes a data stream or signal. ''Codec'' is a portmanteau of coder/decoder. In electronic communications, an endec is a device that acts as both an encoder and a decoder on a signal or da ...
that is used in various
post-production Post-production is part of the process of filmmaking, video production, audio production, and photography. Post-production includes all stages of production occurring after principal photography or recording individual program segments. The ...
video editing software Video editing software, or a video editor is software used performing the post-production video editing of digital video sequences on a non-linear editing system. It has replaced traditional flatbed celluloid film editing tools and analog video ta ...
packages to prevent any wasted time in
transcoding Transcoding is the direct digital-to-digital conversion of one encoding to another, such as for video data files, audio files (e.g., MP3, WAV), or character encoding (e.g., UTF-8, ISO/IEC 8859). This is usually done in cases where a target devic ...
.


Features

Typically, a video server can do the following: * Ingest of different sources :
video cameras A video camera is an optical instrument that captures videos (as opposed to a movie camera, which records images on film). Video cameras were initially developed for the television industry but have since become widely used for a variety of other ...
(multiple angles),
satellite A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope ...
data feed Data feed is a mechanism for users to receive updated data from data sources. It is commonly used by real-time applications in point-to-point settings as well as on the World Wide Web. The latter is also called web feed. News feed is a popular for ...
s,
disk drives Data storage is the recording (storing) of information (data) in a storage medium. Handwriting, phonographic recording, magnetic tape, and optical discs are all examples of storage media. Biological molecules such as RNA and DNA are consi ...
and other video servers. This can be done in different
codecs A codec is a device or computer program that encodes or decodes a data stream or signal. ''Codec'' is a portmanteau of coder/decoder. In electronic communications, an endec is a device that acts as both an encoder and a decoder on a signal or d ...
. * Temporary or definitive storage of these video feeds. * Maintain a clear structure of all stored media with appropriate
metadata Metadata is "data that provides information about other data", but not the content of the data, such as the text of a message or the image itself. There are many distinct types of metadata, including: * Descriptive metadata – the descriptive ...
to allow fast search : name, remarks, rating, date,
time code A timecode (alternatively, time code) is a sequence of numeric codes generated at regular intervals by a timing synchronization system. Timecode is used in video production, show control and other applications which require temporal coordinatio ...
, etc. *
video editing Video editing is the manipulation and arrangement of video shots. Video editing is used to structure and present all video information, including films and television shows, video advertisements and video essays. Video editing has been dramatical ...
of the different
clips CLIPS is a public domain software tool for building expert systems. The name is an acronym for "C Language Integrated Production System." The syntax and name were inspired by Charles Forgy's OPS5. The first versions of CLIPS were developed st ...
* Transfer those
clips CLIPS is a public domain software tool for building expert systems. The name is an acronym for "C Language Integrated Production System." The syntax and name were inspired by Charles Forgy's OPS5. The first versions of CLIPS were developed st ...
to other video servers or
playout In broadcasting, channel playout is the generation of the source signal of a radio or television channel produced by a broadcaster, coupled with the transmission of this signal for primary distribution or direct-to-audience distribution via any ...
directly (via IP interface or SDI) Generally, they have several bi directional channels (record and ingest) for video and audio. A perfect synchronisation is necessary between those channels to manage the feeds.


Video surveillance and inspection

In some surveillance and inspection applications, IP video servers are employed which convert
analog video Video is an electronic medium for the recording, copying Copying is the duplication of information or an artifact based on an instance of that information or artifact, and not using the process that originally generated it. With analog f ...
signals into IP video streams. These IP video servers can stream digitized video over IP networks in the same way that an
IP camera An Internet Protocol camera, or IP camera, is a type of digital video camera that receives control data and sends image data via an IP network. They are commonly used for surveillance, but, unlike analog closed-circuit television (CCTV) cameras, ...
can. Because an IP Video server uses IP protocols, it can stream video over any IP-compatible network, including via a modem for access over a phone or
ISDN Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public switched telephone network. Wo ...
connection. With the use of a video server attached to an analog camera, the video from an existing surveillance system can be converted and networked into a new IP surveillance system. In the video security industry a video server is a device to which one or more video sources can be attached. Video servers are used to give existing analog systems network connectivity. Video servers are essentially transmission/ telemetry / monitoring devices. Viewing is done using a web browser or in some cases supplied software. These products also allow the upload of images to the internet or direct viewing from the internet. In order to upload to the internet an account with an
ISP An Internet service provider (ISP) is an organization that provides services for accessing, using, or participating in the Internet. ISPs can be organized in various forms, such as commercial, community-owned, non-profit, or otherwise private ...
(internet service provider) may be required. Phone apps that send direct security video feed to smartphones from security video servers are another recent security video server application innovation. This allows smartphone users to view security video server feed from anywhere they can use their smartphone.Viewing Your Security Camera on Your Android Smartphone with MPRMS
/ref>


See also

* Broadcast automation and
playout In broadcasting, channel playout is the generation of the source signal of a radio or television channel produced by a broadcaster, coupled with the transmission of this signal for primary distribution or direct-to-audience distribution via any ...
* Centralcasting *
Media server A media server is a computer appliance or an application software that stores digital media (video, audio or images) and makes it available over a network. Media servers range from servers that provide video on demand to smaller personal comput ...
(Consumer)


References

Broadcast engineering Television terminology Video storage Video