Playout
Encyclopedia
In broadcasting, playout is a term for the transmission of radio or TV channels from the broadcaster into broadcast network
s that delivers the content to the audience
. Those networks can consist of terrestrial transmitters for analogue or digital radio
and TV, cable networks
or satellites
(either for direct reception, DTH, or intended for Cable television headend
s).
The playout happens in master control
in a playout area, which can be either situated in the central apparatus room
or in purposely built playout centres, which can be owned by a broadcaster or run by an independent specialist company that has been contracted to handle the playout for a number of channels from different broadcasters.
Some of the larger playout centres in Europe
, South-east Asia and the United States
handle well in excess of 50 radio and TV "feeds". Feeds would often consist of several different versions of a core service, often different language versions or with separately scheduled content, such as local opt outs for news or promotions. There are many Playout service companies, several with a global reach. Such companies include Chello Media (DMC Amsterdam), Encompass Digital Media (inc Ascent), Technicolor, Globecast, Astra Platform Services, WRN Broadcast
, Globecast, Arqiva and many smaller localised companies.
is multi-channel playout that generally uses a broadcast automation
systems with broadcast programming applications from companies including Harris (D-Series and ADC), Vector3 (VectorBox) (Vector MultiPlay), Snell (Morpheus), EVS
, Compunicate, Fission Software, Miranda Omnibus, Pebble Beach, SGT and Abit. These systems generally work in a similar way, controlling video server
s, Video tape recorder
(VTR) devices, Flexicart
s, Audio Mixing console
s, Vision mixer
s and video router
s, and other devices using a serial communications
9-Pin Protocol
(RS-232
or RS-422). This provides deterministic control, enabling frame accurate playback, Instant replay
or video switching. Many systems consist of a front end operator
interface on a separate platform to the controllers - eg a Windows GUI
will present a friendly easy to use method of editing a playlist, but actually control would be done on a platform with a 'real time' operating system such that any large scale playlist amendments do not cause any delays to device control.
Most broadcast automation systems will have a series of common device drivers built in, for example Sony VTR control, Louth Video Disk Control Protocol
(VDCP, a proprietary communications protocol), General Purpose Interface (GPI), or Grass Valley Group M21 Master Control. This ensures that a broadcast automation system bought 'off the shelf' will at least be able to ingest and playout content, although may not be able to take advantage of more efficient methods of control. Most server, and especially most Digital on-screen graphic
and Character generator
(CG) manufacturers will have a specific device driver
for their device, with increasing degrees of complexity, and different automation companies will include these drivers to enhance their product or to fit a customers need.
This is the "traditional" method of Playout Automation, where there are multiple devices. Modern automation systems use the Automated Playout method, which is where the broadcast server fulfills the functions of the multiple devices, and is a self contained system (see Channel in a Box section below).
of devices which begin with content, typically stored on video server
, and ultimately an output, either as an (Asynchronous serial interface
) (ASI) or (Serial Digital Interface
) (SDI) for on pass to a distribution company.
The devices in the chain depend on the service required under the contact with the Channel. Typically a standard television channel would require a Master Control
Video switcher, and therefore a Video router
to allow switching of live sources. This video switcher may include other functions such as keying (graphics) (also known as Down Stream Keyers), Audio Overs for mixing in voice overs (VO) or announcements, and facilitate transitions between events, such as a fade through black or crossfade (also known as mix).
Other devices include:
Graphics inserters - At least one Graphics inserter, or one with several layers. This allows for Station identification
/Logo/Digital on-screen graphic
(Dog or Bug) insertion, and can also be' used for end credits
sequences, coming next graphics or programme information straps
Subtitling inserters - This can be either closed or open - ie in vision as a graphic for all to see, or closed either as an MPEG stream item, Closed Captioning
or World System Teletext
.
Audio servers - An audio playout system would provide scheduled voiceovers
Aspect Ratio Converters - These alter the picture shape or send an embedded signal to allow the material format to be displayed correctly on a particular feed (eg Widescreen on a standard non-widescreen Analogue terrestrial feed)
Some of these more advanced devices require information from the playlist, and so do not tend to use an RS422/232 driver, but a complex XML based system which allows for more complex metadata to be passed, eg a 'Now' or 'Next' Graphic can be created from a template using text information from the playlist.
In recent years there has been a move to replicate all of these functions in a single system, often called a 'channel in a box' solution. These are often cheaper to introduce and allow for a more scalable Playout system. OASYS, Playbox Technology, Miranda Omnibus iTX, Snell and Publitronics are all major providers of this sort of solution.
The playout schedule will have been created in the customer's broadcast programming scheduling system and exported into a format suitable to be used in the Playout system. There is a move to SMPTE-22, known as Broadcast Exchange Format
(BXF) to try to standardise the messaging involved in this interaction.
The resulting playlist is 'loaded' into the appropriate channel of the broadcast automation system in advance of the transmission time. Various processes will take place to ensure the content is available on the correct servers for playout at the right time, typically this involves advance requests to move material from deep storage such as Tape Archives or FTP Clusters to Broadcast Video servers, often using FTP.
On playing out the material, the audio and video signals are usually transported from the playout area to the network via a studio/transmitter link
(STL), which may be fibre backlink, microwave or satellite uplink.
Playout is often referred to as Presentation or Transmission (TX), and is under control of an automatic transmission system
.
Broadcast network
A broadcast network is an organization, such as a corporation or other voluntary association, that provides live television or recorded content, such as movies, newscasts, sports, Public affairs programming, and other television programs for broadcast over a group of radio stations or television...
s that delivers the content to the audience
Audience
An audience is a group of people who participate in a show or encounter a work of art, literature , theatre, music or academics in any medium...
. Those networks can consist of terrestrial transmitters for analogue or digital radio
Digital audio broadcasting
Digital Audio Broadcasting is a digital radio technology for broadcasting radio stations, used in several countries, particularly in Europe. As of 2006, approximately 1,000 stations worldwide broadcast in the DAB format....
and TV, cable networks
Cable television
Cable television is a system of providing television programs to consumers via radio frequency signals transmitted to televisions through coaxial cables or digital light pulses through fixed optical fibers located on the subscriber's property, much like the over-the-air method used in traditional...
or satellites
Satellite television
Satellite television is television programming delivered by the means of communications satellite and received by an outdoor antenna, usually a parabolic mirror generally referred to as a satellite dish, and as far as household usage is concerned, a satellite receiver either in the form of an...
(either for direct reception, DTH, or intended for Cable television headend
Cable television headend
A cable television headend is a master facility for receiving television signals for processing and distribution over a cable television system. The headend facility is normally unstaffed and surrounded by some type of security fencing and is typically a building or large shed housing electronic...
s).
The playout happens in master control
Master control
Master control is the technical hub of a broadcast operation common among most over-the-air television stations and television networks. It is distinct from a production control room in television studios where the activities such as switching from camera to camera are coordinated...
in a playout area, which can be either situated in the central apparatus room
Central Apparatus Room
In broadcast facilities, a central apparatus room , central machine room, or central equipment room , or central technical area , or rack room is where shared equipment common to all technical areas is located. Some broadcast facilities have several of these rooms...
or in purposely built playout centres, which can be owned by a broadcaster or run by an independent specialist company that has been contracted to handle the playout for a number of channels from different broadcasters.
Some of the larger playout centres in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, South-east Asia and the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
handle well in excess of 50 radio and TV "feeds". Feeds would often consist of several different versions of a core service, often different language versions or with separately scheduled content, such as local opt outs for news or promotions. There are many Playout service companies, several with a global reach. Such companies include Chello Media (DMC Amsterdam), Encompass Digital Media (inc Ascent), Technicolor, Globecast, Astra Platform Services, WRN Broadcast
WRN Broadcast
WRN Broadcast, formerly known as WRN, is an international broadcast services company that works with television channels and radio broadcasters, media owners and brands enabling them to deliver content to target audiences worldwide....
, Globecast, Arqiva and many smaller localised companies.
Playout systems
CentralcastingCentralcasting
In terrestrial radio and television broadcasting, centralcasting refers to the use of systems automation by which customised signals for broadcast by multiple individual stations may be created at one central facility.- :...
is multi-channel playout that generally uses a broadcast automation
Broadcast automation
Broadcast automation incorporates the use of broadcast programming technology to automate broadcasting operations. Used either at a broadcast network, radio station or a television station, it can run a facility in the absence of a human operator...
systems with broadcast programming applications from companies including Harris (D-Series and ADC), Vector3 (VectorBox) (Vector MultiPlay), Snell (Morpheus), EVS
EVS Broadcast Equipment
EVS Broadcast Equipment SA manufactures live outside broadcast digital video production systems.Its recorders have become the dominant standard for broadcasters worldwide...
, Compunicate, Fission Software, Miranda Omnibus, Pebble Beach, SGT and Abit. These systems generally work in a similar way, controlling video server
Video server
A video server is a computer based device dedicated to delivering video.Unlike personal computers, being multi-application devices, a video server is designed for one purpose; provisioning video, often for broadcasters. A professional grade video server records, stores, and playout of multiple...
s, Video tape recorder
Video tape recorder
A video tape recorder is a tape recorder that can record video material, usually on a magnetic tape. VTRs originated as individual tape reels, serving as a replacement for motion picture film stock and making recording for television applications cheaper and quicker. An improved form included the...
(VTR) devices, Flexicart
Cart
A cart is a vehicle designed for transport, using two wheels and normally pulled by one or a pair of draught animals. A handcart is pulled or pushed by one or more people...
s, Audio Mixing console
Mixing console
In professional audio, a mixing console, or audio mixer, also called a sound board, mixing desk, or mixer is an electronic device for combining , routing, and changing the level, timbre and/or dynamics of audio signals. A mixer can mix analog or digital signals, depending on the type of mixer...
s, Vision mixer
Vision mixer
A vision mixer is a device used to select between several different video sources and in some cases Compositing video sources together to create special effects...
s and video router
Video router
A Video router or Matrix are used for transporting video signals from sources or inputs to output destinations.- Inputs and outputs :...
s, and other devices using a serial communications
Serial communications
In telecommunication and computer science, serial communication is the process of sending data one bit at a time, sequentially, over a communication channel or computer bus. This is in contrast to parallel communication, where several bits are sent as a whole, on a link with several parallel channels...
9-Pin Protocol
9-Pin Protocol
The 9-Pin Protocol is a two-way communications protocol for the RS-422 D-sub electrical connector interface, in which a bi-direction signal is transmitted over a single, four wire, serial cable to allow the remote control of a wide variety of devices including, reel-to-reel type C videotape video...
(RS-232
RS-232
In telecommunications, RS-232 is the traditional name for a series of standards for serial binary single-ended data and control signals connecting between a DTE and a DCE . It is commonly used in computer serial ports...
or RS-422). This provides deterministic control, enabling frame accurate playback, Instant replay
Instant replay
Instant replay is the replaying of video footage of an event or incident very soon after it has occurred. In television broadcasting of sports events, instant replay is often used during live broadcast, to show a passage of play which was important or remarkable, or which was unclear on first...
or video switching. Many systems consist of a front end operator
Operator (profession)
An operator is a professional designation used in various industries, including broadcasting , computing, customer service, physics, and construction. Operators are day-to-day end users of systems, that may or may not be mission-critical, but are typically managed and maintained by technicians or...
interface on a separate platform to the controllers - eg a Windows GUI
Gui
Gui or guee is a generic term to refer to grilled dishes in Korean cuisine. These most commonly have meat or fish as their primary ingredient, but may in some cases also comprise grilled vegetables or other vegetarian ingredients. The term derives from the verb, "gupda" in Korean, which literally...
will present a friendly easy to use method of editing a playlist, but actually control would be done on a platform with a 'real time' operating system such that any large scale playlist amendments do not cause any delays to device control.
Most broadcast automation systems will have a series of common device drivers built in, for example Sony VTR control, Louth Video Disk Control Protocol
Video Disk Control Protocol
Video Disk Control Protocol 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 the Louth Protocol...
(VDCP, a proprietary communications protocol), General Purpose Interface (GPI), or Grass Valley Group M21 Master Control. This ensures that a broadcast automation system bought 'off the shelf' will at least be able to ingest and playout content, although may not be able to take advantage of more efficient methods of control. Most server, and especially most Digital on-screen graphic
Digital on-screen graphic
A digital on-screen graphic is a watermark-like station logo that many television broadcasters overlay over a portion of the screen-area of their programs to identify the channel...
and Character generator
Character generator
A character generator, often abbreviated as CG, is a device or software that produces static or animated text for keying into a video stream. Modern character generators are computer-based, and can generate graphics as well as text...
(CG) manufacturers will have a specific device driver
Device driver
In computing, a device driver or software driver is a computer program allowing higher-level computer programs to interact with a hardware device....
for their device, with increasing degrees of complexity, and different automation companies will include these drivers to enhance their product or to fit a customers need.
This is the "traditional" method of Playout Automation, where there are multiple devices. Modern automation systems use the Automated Playout method, which is where the broadcast server fulfills the functions of the multiple devices, and is a self contained system (see Channel in a Box section below).
Playout devices
Playout will usually involve a airchainAirchain
In broadcast engineering for radio or television, the airchain or transmission chain is the path or route an audio or video signal takes on its way through a radio station or television station.The airchain begins with cameras, microphones, CD players, turntables, telephone hybrids, video tape...
of devices which begin with content, typically stored on video server
Video server
A video server is a computer based device dedicated to delivering video.Unlike personal computers, being multi-application devices, a video server is designed for one purpose; provisioning video, often for broadcasters. A professional grade video server records, stores, and playout of multiple...
, and ultimately an output, either as an (Asynchronous serial interface
Asynchronous serial interface
Asynchronous Serial Interface, or ASI, is a streaming data format which often carries an MPEG Transport Stream .An ASI signal can carry one or multiple SD, HD or audio programs that are already compressed, not like an uncompressed SD-SDI or HD-SDI . An ASI signal can be at varying transmission...
) (ASI) or (Serial Digital Interface
Serial Digital Interface
Serial digital interface is a family of video interfaces standardized by SMPTE. For example, ITU-R BT.656 and SMPTE 259M define digital video interfaces used for broadcast-grade video...
) (SDI) for on pass to a distribution company.
The devices in the chain depend on the service required under the contact with the Channel. Typically a standard television channel would require a Master Control
Master control
Master control is the technical hub of a broadcast operation common among most over-the-air television stations and television networks. It is distinct from a production control room in television studios where the activities such as switching from camera to camera are coordinated...
Video switcher, and therefore a Video router
Video router
A Video router or Matrix are used for transporting video signals from sources or inputs to output destinations.- Inputs and outputs :...
to allow switching of live sources. This video switcher may include other functions such as keying (graphics) (also known as Down Stream Keyers), Audio Overs for mixing in voice overs (VO) or announcements, and facilitate transitions between events, such as a fade through black or crossfade (also known as mix).
Other devices include:
Graphics inserters - At least one Graphics inserter, or one with several layers. This allows for Station identification
Station identification
Station identification is the practice of radio or television stations or networks identifying themselves on air, typically by means of a call sign or brand name...
/Logo/Digital on-screen graphic
Digital on-screen graphic
A digital on-screen graphic is a watermark-like station logo that many television broadcasters overlay over a portion of the screen-area of their programs to identify the channel...
(Dog or Bug) insertion, and can also be' used for end credits
End Credits
"End Credits" is the first single from Drum and Bass duo Chase & Status' second studio album No More Idols. The single was co-written, co-produced and features vocals from Plan B and was released on 29 October 2009, reaching a peak position of No. 9 in the UK Singles Chart...
sequences, coming next graphics or programme information straps
Subtitling inserters - This can be either closed or open - ie in vision as a graphic for all to see, or closed either as an MPEG stream item, Closed Captioning
Closed captioning
Closed captioning is the process of displaying text on a television, video screen or other visual display to provide additional or interpretive information to individuals who wish to access it...
or World System Teletext
World System Teletext
World System Teletext is the name of a standard for encoding and displaying teletext information, which is used as the standard for teletext throughout Europe today....
.
Audio servers - An audio playout system would provide scheduled voiceovers
Aspect Ratio Converters - These alter the picture shape or send an embedded signal to allow the material format to be displayed correctly on a particular feed (eg Widescreen on a standard non-widescreen Analogue terrestrial feed)
Some of these more advanced devices require information from the playlist, and so do not tend to use an RS422/232 driver, but a complex XML based system which allows for more complex metadata to be passed, eg a 'Now' or 'Next' Graphic can be created from a template using text information from the playlist.
In recent years there has been a move to replicate all of these functions in a single system, often called a 'channel in a box' solution. These are often cheaper to introduce and allow for a more scalable Playout system. OASYS, Playbox Technology, Miranda Omnibus iTX, Snell and Publitronics are all major providers of this sort of solution.
Workflow
A common workflow is for the broadcast automation system to have a recording schedule to ingest material from a satellite or line feed source and then time-shift that material based on a playlist or schedule.The playout schedule will have been created in the customer's broadcast programming scheduling system and exported into a format suitable to be used in the Playout system. There is a move to SMPTE-22, known as Broadcast Exchange Format
Broadcast Exchange Format
BXF standardizes the communication of three basic types of data exchange defined by a set of SMPTE standards.1. Schedule and as run information2. Content metadata3. Content movement instructions- A brief summary of BXF :...
(BXF) to try to standardise the messaging involved in this interaction.
The resulting playlist is 'loaded' into the appropriate channel of the broadcast automation system in advance of the transmission time. Various processes will take place to ensure the content is available on the correct servers for playout at the right time, typically this involves advance requests to move material from deep storage such as Tape Archives or FTP Clusters to Broadcast Video servers, often using FTP.
On playing out the material, the audio and video signals are usually transported from the playout area to the network via a studio/transmitter link
Studio/transmitter link
A studio-transmitter link sends a radio station's or television station's audio and video from the broadcast studio to a radio transmitter or television transmitter in another location....
(STL), which may be fibre backlink, microwave or satellite uplink.
Playout is often referred to as Presentation or Transmission (TX), and is under control of an automatic transmission system
Automatic transmission system
An automatic transmission system is an automated system designed to keep a radio transmitter and antenna system running without direct human oversight or attention for long periods.-History:In the early days of radio, an operator, technician or electrical engineer...
.