04. TV Studio and Production Systems

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Television is defined as the electronic delivery of moving images and sound from the source to the receiver. Generally, television station facilities resemble that of radio station and consist of studio and transmitter areas. The studio workspace can be divided as follows: the studio, the control room, post-production and master control.

4.1 Studio Characteristics
The studio is the large space where the set for for a television program is located. For a news program, the anchors deliver the newscast live from an anchor desk to the viewers. Normally, studios contain more than one set for different programs. The studio will contain smaller subsets that are used in conjunction with the newscast. Basically, a TV studio has two workspaces: studio and control room.

4.1.1 The Studio
The studio space is shown in figure 4.1. It is required to control light and sound in the studio for different program setup. The studio floor is flat and clean so that the cameras can move smoothly around the set. The walls of the studio can be constructed of many types of material such as cinderblock, brick, concrete etc. If the walls of the studio are stretched fabric, special care should be taken not to touch, puncture or tear the fabric membrane as it is designed to absorb sound.

Large curtains of fabric called cycloramas are common in television studios on the front side of the physical wall. Cycloramas come in many colors, and most studios will have two or more that surround all or most of the studio. The ceiling of the studio is high in order to accommodate set materials and the studio lighting system. The studio ceiling may be painted black in order to prevent light reflection.

The most prominent future near the ceiling is the lighting grid. The lighting grid is made up of pipes called battens, and the lighting instruments hang from these with large c-clamp mounts. Another item that will be located either in the studio or in the control room is the lighting board, which is a computerized on/off switch for each lighting instrument. All of the instruments can be controlled at once using the lighting board.

The set for the typical television news program is often centered around a desk where the anchors sit to deliver the program content. In most studios, the desk is part of a permanent set that may include risers and flats. Risers are the platforms to raise the height of the desk, and the flats are vertical panels to provide a background.

The supervisor of the studio is called the Floor Director. his primary job is to communicate with, or cue, the anchors in the studio space. He can hear the commands of the Program Director using an intercom system that links the studio to the control room. He will cue using voice commands or by using hand signals when a microphone is active. The talents of the news program and the anchors work in the studio during the live portion of the program. Often, the anchors will spend the last few minutes before the show goes live reviewing and editing a paper copy of the script.
Figure 4.1 TV Studio Workspace
4.1.2 Control Room
The control room is usually nearby the studio space. Often the control room is attached to the studio by a common wall. The control room is used to control the operations of the studio. Control rooms are usually dedicated to a particular studio and may control more than one studio. A wide array of audio and video processing device will be installed in the control room. As shown in figure 4.2, all control rooms will differ to some extent, however, the common set up we can see here are a monitor wall, an audio console, a video switcher, a teleprompting computer, a graphics computer, an engineering space and a section for VTR control. 

The monitor wall in the control room is centered around two larger video monitors that display preview video and program video. The program video monitor displays the video source that is active or live. The preview monitor show the video source that is next or on queue for a program. Smaller video monitors surround these two large monitors and display the video sources available for use by the production team. These smaller monitors will show studio cameras, microwave feeds, satellite feeds, graphics and other video sources that can be activated or routed to preview and program.
Figure 4.2 Television Control Room
Pictures monitors are used to check both program content and technical quality of the video signal. They are used extensively in production studios and throughout all broadcast facilities. An increasing use of other display technologies, including flat panel plasma and liquid crystal displays (LCD) have replaced the traditional cathode ray tube (CRT) displays for picture monitors.

4.2 Television Production Chain
A TV production studio consists of a set of broadcast equipments. These equipments range from a studio camera to different tape recorders connected to the video switcher. The video output from the switcher and audio coming from the nearby audio mixer can be routed to the main program bus or to the video server. The typical TV production chain is shown in figure 4.3 below.
Figure 4.3: TV Production Chain Flow
4.2.1 The Video Switcher
A prominent feature of the control room is the video switcher, or vision mixer, which is a video selection device. The switcher control the video sources that are activated to preview and. The final video feed from the video switcher is called video program. A switcher will be used as the production, on-air vision mixer or a router. The production switcher refers to creating finished video that will ultimately be seen by a viewing audience. The on-air switcher generally coordinates sources of finished production and sends output directly to the transmitter. It will be switching between various videotape machines, network feeds, satellite feeds, and the studio. The final switcher application is for routing.

The main function of a production switcher is to either switch or cut between two video sources, or combine them in a variety of ways. The principal methods used to combine video are mixing, wiping and keying. A production switcher consists of two main sections:
- An input selection matrix which provides the input switcher functions.
- Video mixing amplifiers usually called the mix and effects (mix/effects) system, which provides the combining functions.

A mixing amplifier selects the proportions of the two video signals being combined and adds the result to form the output signal. A selection of different wipe patterns is provided to allow the operator to produce a variety of wipe effects between one picture and another. These units also provide the ability to key or switch from one picture to another under control of a video or external input signal. Keying is typically used for adding captions or titles to the picture. Modern switchers usually provide all the above functions of mixing, wiping and keying in single mix/effects (ME) amplifier. All production switchers are capable of at least three transitions: cuts, fades and dissolves. Cuts are instantaneous from one picture to another. A fade-in is a transition that starts with a blank screen that grows progressively brighter until the full picture appears at its normal intensity. A fade out is the opposite, beginning with a full picture that decreases in intensity to a blank screen. A dissolve is much like a fade in such a way that as one picture is fading out, another is fading in, and there is always picture on the screen.

The configurations of production switchers vary in a number of ways to accommodate production requirements such as number of inputs, number of M/E systems, and M/E functions. Some switchers provide additional optional features such as digital video effects. An effects system is often used in conjunction with a production switcher to provide picture manipulation. The switcher has two outputs. The preview output is going to a preview monitor for the director's use. The program output is going to a distribution amplifier (DA), and from there one output goes to the program monitor and another one goes to the on-air switcher, where it is fed to the transmitter. The other program DA outputs are going to videotape recorders (VTRs) where the program is recorded.

4.2.2 The Audio Board
The audio board may be located in the control room or in a smaller adjacent room called the audio booth. The audio board is an audio selection device and the audio feed from the audio board is called Audio Program. Audio monitors, heavy-duty speakers, will be located near the monitor wall to permit the control room crew to listen to the program. Common audio sources that are selected include the studio microphones, audio from the video tape recorders, an audio or video file server, a satellite feed, a microwave feed, and CD players. In addition, the audio board itself is an audio source to provide test tones.

4.2.3 The Graphics Computer
The graphics computer is the other major equipment in TV control room. The graphics computer can create, store and recall two kinds of graphics: caption based character generator (CG) and images from electronic still-store (ESS). CG is the creation of alphanumeric text as a video signal. A good example of CG is when the anchor's name is keyed or layered over a camera shot or at the end of the program when the credits are rolled down. The ESS function centers around still-image processing. The graphics computer can store high-resolution images, capture images from other video sources, and combine these images with CG to create entirely new graphics. ESS is used when a still image of a reporter is displayed during a phoned-in report or a report without video.
4.2.4 Video Tape Recorders 
The television program is recorded and any pre-recorded material needed for the show is controlled from the tape operator. He/she is responsible for operating numerous video tape recorders or other computer-based video playback devices. Pre-recorded material is then rolled from tape or a video server as needed and in order. In many control rooms, the VTR racks are located in an adjacent room or by the side of a common control room. The number of VTRs available will vary by facility.
4.2.5 The Prompting Computer
Another computer in the control room is the prompting computer. The prompting computer transforms the script for the show into a scrollable video signal that is transmitted to a viewing system on the front of the studio cameras. The prompter position controls the word processing and organization of the final script for the program. The collation of all of the stories occurs in the prompting computer, and all final changes to the script are made by the News/Program staff through this computer system.

4.2.6 Patch Panels and Signal Routing
Located on the wall of the studio are hookup jacks for audio, video, clock, intercom, and other signals that pass between the studio and the control room. These hookup jacks are located together in a patch panel. Prior to the show, the person responsible for audio in the control room will connect cables to route the audio signals from the microphones to a patch panel and then into the control room. In some studios, the audio is routed to the patch panel through an audio snake that permits multiple mic hookups. Program video may need to be routed to monitors, intercom connections may need to be made, and even cameras can be hooked into different panels. In some cases, a routing switcher may be found inside of the studio as well. Routing switchers permit audio and video signals to be sent to different and sometimes multiple locations in the studio and control room. 

4.3 Post-production and Master Control
Post-production refers to a space in the television station where editing activities are conducted. In some stations, editing rooms are available and contain the equipment necessary for creating any prerecorded material that can be used in the newscast. As many stations move to server-based, nonlinear systems or portable editing systems, editing can occur just about anywhere at the station or in the filed. Master Control refers to the transmission control of the television station itself. Incoming and outgoing microwave and satellite signals are received/transmitted in this area and the final output mix of the station is controlled here.

All audio and video signal routing is the responsibility of a technical staff. Live feeds will need to be routed as sources to the control room on an as-needed basis. Likewise it is also needed for appropriate routing of video and audio signals both to and from the VTRs. He also performs any equipment troubleshooting during routing procedures. He is responsible for the camera control units (CCUs) that remote controls for the studio cameras during the telecast. The cameras must be white-balanced and properly framed. The technical person can adjust how each camera sees individual colors by using the waveform monitor and vector scope and it ensures the cameras are balanced or matched. During the program, he can use the CCUs to make adjustments to the iris settings on the camera lens or to adjust the strength of the video signal level. 

4.4 Production Control
The production directors leads and supervises the entire production team. During the actual program, he cues or calls command to the production crew using the intercom system. He usually does not operate any particular piece of equipment but may use the script to call audio and video transitions for the duration of the program. During the program, when the studio is live, he is at the top of the personnel hierarchy. 
The person responsible for the content of the program, such as the scripts, the stories and the tapes included, is the producer. Prior to the broadcast, the producer works with news, weather and sports personnel to plan and construct the newscast. He/she is located in the control room during the show and may make content changes on the fly that the production crew will need to respond to. The producer may also need to communicate with the anchors during the show using the interrupt fold back (IFB) system. 

The production tasks associated with audio and video control in the production environment are the primary responsibility of the audio technician and the technical director. Usually, the audio control space will be located either in the control room itself or in an isolated booth nearby. The booth style of audio facility permits the technician to concentrate on the characteristics of the program audio with greater clarity. The primary job of the technical director is to operate the video switcher and thus controlling Video Program. Video Program is the final compilation of video sources that is sent out for transmission or recorded.

4.5 Cameras
A video camera performs the complex task of creating an electronic image of a real scene. The scene may range from scenes with large dynamic range that must be compressed to fit within the capability of the video system, to scenes with marginal illumination. Video camera designs are broadly categorized by operational applications for studio, News gathering, Field production. 
In all these cases, broadcast quality picture signals are provided. Broadcast quality may be defined as the quality picture obtainable consistent with the circumstances surrounding the event to be televised, and that which will satisfy viewer requirements. The television cameras consist of a camera head connected via a multi conductor cable to a rack-mounted camera control unit (CCU).

4.5.1 Optical System
The optical system of a camera is used to form a precise image of the original scene on the surface of the imaging devices. The optical system consists of a lens to capture the image, optical filters to condition the image, a color separation system to split the incoming light into the three primary color components. Light from the scene being televised is imaged on the targets of the pickup tubes by an objective lens, either of a fixed focal-length variety or a variable focal-length zoom type. The primary color images are derived by means of a dichroic mirror or split cube color-separation optical system.

The relatively low-level video-output signals from the pickup tubes are amplified by preamplifiers and corrected in amplitude-frequency response characteristics for losses in the pickup-tube coupling circuits. This is followed by line-by-line blanking-level clamping, image enhancement for aperture losses, and gamma correction for the linear transfer characteristics of the pickup tube. All three color signals are color corrected by linear matrixes and gamma corrected. Gamma correction is applied to compensate for the essentially liner transfer characteristics of the pickup tube.

The corrected and processed color signals are mixed with system blanking and clipped to produce three color signals for encoding to a composite 525- or 625-line signal. A color camera must produce video signals that complement the characteristics of the three phosphor standard additive display tube. A high-efficiency dichronic light splitter is commonly used to divide the optical image into three images of red, blue and green. There are several important distinction that characterize studio cameras. The difference in size and cost are the result of these major distinctions and they are:
- The highest attainable picture quality.
- Multicamera program, rather than single-camera production, designs.
- Full complement of features and accessories for broadcast production.

4.5.2 The Viewfinder
The viewfinder on the camera show the operator what the camera sees. When the camera is powered up, the viewfinder will also be receiving the image. However, it is common to turn the brightness or contrast control to prevent the monitor unit from burning in an image. The Camera man will need to adjust the viewfinder image and the viewfinder position. Located on the front of the viewfinder will be a tally light. The camera unit is operated both manually and by remote. The remote control for the camera is called the camera control unit (CCU).

The camera is usually powered by remote. The teleprompter equipment mounted to the front of the camera unit will need to be powered up. A separate on/off switch will be located on the prompter. Like any video monitor, the prompter unit may be able to monitor multiple video inputs.

4.5.3 Headset, Beltpack and XLR cable
Once the camera is ready to go, the Camera Operator will need to locate an intercom unit in order to communicate with the control room and the rest of the production crew. The basic intercom unit has three parts: the headset, the beltpack, and an XLR cable of some length that will hook into the patch panel. The headset is connected to the beltpack. The beltpack is connected to the patch panel with the XLR cable.

Figure 4.5 A Studio Camera and its Components

4.5.4 Charge Coupled Devices (CCD)
The CCD, an analog device, is a transducer that converts light into electrons. Unlike the homogeneous photo-conductive surface of the plumbicon tube, the CCD is a geometric array of separate and discrete opto-electrical sensors. They are the parts inside of the camera that change the light focused on them by the camera lens into electrical signals. Each sensor develops its own electrical charge proportional to the amount of illumination that falls on it. The aggregate aesthetic quality of the picture is a complex combination of the elements such as aspect ratio, horizontal resolution, vertical resolution, colorimetry, gray scale, total dynamic range for still images, and other dimensions, such as temporal resolution and lag, for moving images.

CCDs have been developed from the solid-state silicon chip technology that has made computers faster, smaller, more powerful, and cheaper. These chips are laid out with rows of photosensitive element called pixels. The number of pixels on a CCD is defined by its matrix. For example, a matrix of 704×480 would indicate that there are 704 pixels places across the screen horizontally in each of 480 vertical rows. When light hits one of these pixels, a distinct electrical voltage is created. All of these discrete voltages are read off left to right and top to bottom into a memory. The memory is then fed out, horizontal line by horizontal line, in sync with the rest of the system. Once the face of the CCD has been cleared, a new image forms and the process is repeated.

4.5.5 Display Devices
Important technology trends for the principal display technologies include Cathode Ray Tube, Liquid Crystal Display, Plasma/Gas Discharge, and Electroluminescent. Key evaluation metrics for any display include the following:

  • Overall luminous efficiency
  • Viewability (brightness and contrast)
  • Uniformity of reproduction, both large-and small-area
  • Gray scale
  • Color capability, gamut, and accuracy
  • Life expectancy and reliability
  • Cost of the display device and supporting circuitry.

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