The boom in the broadcast and live environments: PTZ CAMERAS
By CARLOS MEDINA, Audiovisual Technology Expert and Advisor
TV programs such as Big Brother, Survivors or Love Island, theaters of all kinds, religious sites, conference rooms and numerous events/concerts with multi-camera recordings have something in common: the use of PTZ cameras.
This type of camera has achieved the recognition of audiovisual professionals in the broadcast environment and in multi-camera coverage of live events thanks to the technology they feature and to the enormous benefits they offer nowadays.
But it hasn’t always been this way. The origin of this type of camera comes from the field of security and video surveillance: the use of cameras for closed circuit TV (CCTV); a camera that only offered the ability to capture from a single point of view, determined by the physical location of the device with respect to the space to be displayed. The result of these initial cameras were frames on a fixed plane, without camera movements, lacking in image quality and with little visual angle.
And yet they were key for video surveillance work due to their multiple and versatile placement in view of their compact size and their very simple operation and configuration. Not to forget the ability to have real-time images of what is happening and the option of having recording material 24/7 at a low cost, replacing the expense of security personnel.
A curious fact: the first use of a closed-camera TV circuit was documented to have been carried out by the German army thanks to Siemens in 1942. They were very basic black and white systems and were used for missile test observation in preparation for long-distance military strikes.
At present, after the different historical episodes that international terrorism has left us and the continuous dissemination of news on robberies and thefts, security cameras and video surveillance are all around us in our daily work: from those used in traffic, on the streets and squares, even in banks, stores and shopping centers (retail sector) up to the most private use in houses and homes.
At present time, the technology that has been developed is very sophisticated in order to obtain excellent results in video surveillance matters: night vision, sound activation, thermal imaging cameras with automatic tracking and face detection, among other features.
The use of PTZ cameras in the broadcast TV environment and live events has been the result of two circumstances. In the first place, the inception of television content based on reality television where the landmark audiovisual reference is Big Brother, born in September 1997 as an original idea of the John de Mol Produkties (Endemol) production company. This type of program saw the need to “watch” the contestants day and night through cameras that would go unnoticed in the contestants’ home.
Secondly, an audiovisual production that is being increasingly enriched with points of view from numerous cameras with the aim of generating showiness at live events. Audiovisual content that can be enjoyed on various large-format displays by the attendees to the event. Live events have to make the most of the spaces within the stages and manage tight budgets, as well as hire the right human team to operate the different cameras.
In this historical, social and economic context, PTZ (an acronym for pan-tilt-zoom) cameras became a major asset in television programming, entertainment and live shows. A PTZ is a remotely-controlled video camera that is compact in size (+/- width: 158.4 x height: 177.5 x depth: 200.2 mm), lightweight (1.5Kg to 5 Kg) and having a wide range of possibilities for planning due to its smooth and silent PAN (P), TILT (T) and zoom (Z) movements.
PAN is a horizontal movement of the camera body (from left to right or vice versa) on its own central axis and without physical movement of the camera. TILT shares the same characteristics but it is a movement of the camera body in a vertical direction (from top to bottom or vice versa). And ZOOM is the internal movement of the lenses within the camera optics that allows us to have different focal lengths without changing the lens, thus being able to go from a wide angle to a normal focal length or to a telephoto lens (various combinations that depend on the type and design made by the manufacturer of the broadcast optics).
Therefore, PTZ cameras neither are nor are called IP cameras, POV cameras, Bullet cameras, Robotic cameras, PoE (Power over Ethernet) cameras, Built-in Webcams, Standalone Webcams, Pencil cameras, or action cameras; although they all share quite a few technical specifications and protocols in common.
It now is time to learn a little more about PTZ cameras. Let’s see their specifications in aspects such as the cameras themselves and lenses, video format, system requirements, interface, add-ons and accessories required.
High-end PTZ cameras in the audiovisual industry have the same features or operations as any other type of camera used in this sector (an ENG -Electronic News Gathering- camera, for instance), as follows: front and rear tally, iris control, focus control (including face detection and tracking), ND filter, color bars, scene files, optical image stabilizer (OIS), electronic image stabilization system (EIS), changes in shutter speed, gain control, white balance, gamma, knee and detail settings, synchro scan and variable frame rate (VFR), among others.
We can even find camera models that support HDR (Canon CR-X500) and both BT.709 and BT2020 color spaces.
PTZs are a great integrated solution without complications when it comes to cabling, without added technical elements (such as deploying robotics for camera movements) with excellent size and weight. They can be operated with ceiling/wall mount, tabletop or tripod, with an ‘image rotation’ function that automatically ensures the correct output orientation in any installation environment.
Depending on the construction materials and the protection index of the base and camera body housings, we can find PTZ cameras for indoors and outdoors that are able to withstand different weather conditions (Canon CR-X500 with an IP55 index, to work from -15°C to +40°C and up to 90% humidity).
Control and camera setup operations are carried out by an operator remotely by means of an IR remote control and, above all, with the help of a joystick controller and/or specific software (IP Pipe from LiveU or PC PTZ Control Panasonic Center for instance) with which you can operate one or more PTZ cameras.
The Sony BRC-H900 PTZ allows operating large-scale systems of up to 112 cameras controlled over standard IP networks by adding the BRBK-IP10 IP remote control card and the RM-IP10 remote control.
Regarding technical parameters of PTZs, worth mentioning is the fact that at present those with a single camera sensor, usually CMOS (type 1.0, type 1/2.5 or type 1/2.3) are the most common; They allow support and sharing of FHD resolution video signals, although there are already PTZ cameras in UHD and 4K on the market.
As we have already mentioned, every PTZ camera features a fixed lens with variable focal length (zoom) having its own optical movements and offering different focal lengths (some models providing x24 – Sony BRC-H800 and even x30 – Minrray UV950AS) and some with the possibility of digital zoom.
When choosing a PTZ, it is important to know its response at a rotation angle/tilt and its speed of movement, as well as under the settings that the PAN involves. These values are measured in degrees and speed in seconds: For example a Panning Range ± 175° or tilt dynamic speed between 5° and 300° per second.
In this sense, most manufacturers of this type of camera offer what is known as the number of preset positions allowing us to mark and remember the PAN, TILT and ZOOM positioning of the camera with regards to the event or content to be captured. For example, the Aver CAM PTZ330 model gives us the possibility of 255 different locations.
One of the reasons that has driven the rise and success of PTZs in audiovisual and live is their connectivity. Both in transmission of video and audio signals, even of several signals simultaneously (12G-SDI, 3G SDI, HDMI, USB 3.0, IP Streaming and CVBS) and with regards to control and communication protocols.
At present, there is no single PTZ camera not being suitable for inclusion in complex configurations under VISCA functionality through RS232 and RS422 ports and over IP (RJ-45) or supporting NDI| HX, RTP/RTSP/RTMP/ SRTP, TCP/IP, UDP/IP, HTTP, HTTPS, FTP, DHCPv6, DNS, NTP, ICMPv6 (MLD), RTSPoverTCP, RTSPoverHTTP, SSL (TLS), or MultiCast/UniCast standards like the Panasonic AW-UE100 model.
VISCA is a professional PTZ camera control protocol. It was designed by Sony to be used in several of its block and surveillance OEM (Original Equipment Manufacturer) cameras. It is based on RS232 serial communications at 9600 bit/s, 8N1, without flow control normally through a DB-9 connector, but can also be on 8-pin DIN, RJ45 and RJ11 connectors used in daisy-chain configurations.
NDI®, named after Network Device Interface, is a network device interface technology that involves the exchange of video information through IP over Ethernet networks. This protocol was first implemented by NewTek Company in 2015 at the International Broadcast Conference (IBC) in Amsterdam, combining SDI compatibility with IP flexibility. NDI supports integration with ASPEN, SMPTE 2022, and other emerging standards.
It is a high-quality, low-latency IP video transmission standard that is popular for video production. It is an easy way to connect live video sources between computers that was initially adopted by the live video production industry for use in software including Wirecast, vMix, LiveStream Studio, OBS (via plugin), xSplit and NewTek TriCaster. Nowadays, NDI® is used in a broad range of video applications, including broadcasting, distance learning, and video communications.
Over the years, NDI® has launched new connectivity options like NDI | HX®, which stands for ‘High Efficiency’ (2017) and provides additional flexibility for bandwidth control when sending video over a LAN. NDI | HX® has also made it possible to use NDI® video over WiFi and other limited bandwidth networks. 2020 saw the announcement of NDI | HX®2 with a series of new optimization improvements such as NDI® HB, the ‘High Bandwidth’ option.
RTP (Real-time Transport Protocol) is the real-time transport protocol for the transmission of information in real time, such as audio and video in a video conference. It was developed by the IETF Audio and Video Transport Working Group, first published as a standard in 1996 as RFC 1889, and later updated in 2003 in RFC 3550, which is the Internet standard STD 64.
RTCP stands for Real Time Transport Protocol, and it is defined in RFC 3550. RTCP works hand in hand with RTP. RTP does the sending of the data, where RTCP is used to send the control packets to the participants. The primary function is to provide feedback on the quality of service offered by RTP.
RTSP (Real Time Streaming Protocol) is a real-time streaming protocol for controlling the transmission of audio/video between two endpoints and facilitating transport of low latency streaming content over the Internet. First developed by Netscape Communications, Progressive Networks (now RealNetworks), and the Columbia University, the RTSP specification was published by the Internet Engineering Task Force in 1998. Version 2.0, released in 2016, modified the initial version in an effort to shorten round-trip communication with the media server.
SRTP, also known as Secure Real-Time Transport Protocol, is an RTP extension profile that adds security features, such as message authentication, confidentiality, and response protection, mostly intended for VoIP communications. SRTP uses authentication and encryption in order to minimize the risks of attacks such as service denials. It was published in 2004 by the IETF (Internet Engineering Task Force) as RFC 3711.
The COVID 19 crisis has only accelerated the use of PTZ cameras. As they are controlled without the need for a camera operator, PTZs have made it possible to work under health safety regulations according to the social distancing measures imposed and the reduction of human resources in TV programs and live events. PTZs have become a true tool for the salvation of the show and the live multi-camera option. A single operator can control multiple PTZ cameras remotely from a desktop, making it possible to record an event or broadcast live from different points of view without needing to be physically there.
The manufacturers of PTZ cameras that dominate this market are Sony (with their BRC or SRG range, with successful models such as BRC-X1000 or BRC-H800) and Panasonic (their AW-UE and AW-HE series, the AW-UE100 or AW-HE130 as camera reference). Although other brands such as Canon (CR-X and CR-N ranges), JVC (KY-PZ series) and even Minrray, Marshal, Aver CAM, Logitech or Digitex, are trying to gain a foothold in the face of the high demand seen for these types of cameras.
Each of the aspects that we have discussed are on their own sufficient reason behind the rise of PTZ cameras in the broadcast audiovisual environment and multi-camera content applied live in the immediate present, and for the future we are being announced as featuring virtual studios, virtual reality (VR) and augmented reality (AR), as well as new protocols such as FREE-D, a standard that transmits camera tracking data.