Streaming Media: PTZ Camera Buyers Guide

A PTZ camera is a video camera that may be controlled by a remote controller. Pan, Tilt, and Zoom (PTZ) are the three major movement tasks that a camera operator would historically do on a tripod-mounted video camera to adjust the horizontal field, vertical field, and focal length. Because PTZ cameras offer remote or robotic control and operation, the operator does not need to stand behind the video camera to manually operate it. By removing the camera operator, the camera position requires less of a footprint—in fact, if the PTZ camera is mounted to a wall or column, it may require no physical footprint at all.

The abbreviation "PTZ" does not reflect everything these cameras can accomplish remotely, nor does it cover all of the capabilities that an operator would typically handle via a video camera menu system and lens settings. One of the primary advantages of a PTZ camera is its ability to power the camera as well as transmit video and audio via a single ethernet line.

Controllers and Connection Protocols

Many PTZ cameras have a basic IR remote controller that resembles a television remote control. This may be enough for some studio scenes if the sitting performer does not move and many cameras are employed. Some PTZ cameras may be allocated a camera number (through a dip switch or software control) and controlled individually using a remote control. Hardware and software controllers are increasingly routinely employed in sophisticated productions.

The majority of PTZ camera manufacturers sell hardware PTZ controllers that link to the PTZ camera through wired or wireless connections. The connections used to connect gear, as well as the underlying communication protocols such as the Sony VISCA protocol and RS-422, might vary.

Because of the differences in protocols and connectivity, you cannot use all hardware PTZ controllers with all PTZ cameras. Skaarhoj, for example, makes third-party PTZ controllers that are built to operate with certain PTZ protocols, and they list numerous compatible PTZ cameras for their various models.

A joystick controller is commonly used in hardware controllers to control pan and tilt. On some versions, twisting the joystick knob controls the zoom; others have a zoom rocker; and yet others have both choices. PTZ controllers may record and remember preset scenes and motions in addition to altering camera parameters such as white balance, iris, frame rate, resolution, gain, and others.

The operator can utilize the joystick controller to pan, tilt, and zoom in real time or rely on preset locations and camera settings saved before to an event. When operating several PTZ cameras at the same time, the ability to remember presets is very vital.

I utilize two or three cameras for the majority of my PTZ productions, and I limit my PTZ modifications on the live (or program) camera to small framing fixes. Before I go live, I change each of my other cameras in my preview monitor. When using many cameras for live productions, you have the option of designating one as a wide camera and operating the other cameras. This is similar to using camcorders with operators, however you don't need several camera operators. On a single PTZ controller, a single PTZ operator may operate many PTZ cameras.

Many PTZ cameras, like a lot of digital video and audio technology these days, come with software controllers from their makers. This program provides comparable functionality to a hardware controller, however the settings menus on a computer are frequently easier to browse, but the camera movement controls on a hardware controller are easier to change. I usually start with the software and then switch to the hardware to control the camera.

Most PTZ control software includes a video preview, but the quality is sometimes inadequate, and crucial modifications should always be made using the best quality output signal possible on calibrated monitors. This low-quality preview first caused me to believe that my PTZ cameras were creating a very noisy image in the shadows, until I examined the PTZ output at full resolution and discovered that it was just the low-res preview that was compressing that signal too much.

PTZ cameras can also communicate with streaming software such as vMix and OBS, and when combined with a third-party remote controller, such as an Xbox game controller, this solution provides a less expensive way to obtain hardware controls at a fraction of the cost of pricey hardware controllers.

Outputs

HDMI and HD-SDI are the two most frequent video outputs on current PTZ cameras (see Figure 4). These are well-known digital connection standards, with the typical advantages and disadvantages, such as HDMI's lack of a locking connector and shorter cable length runs than HD-SDI's locking BNC-style connector. Both formats have distinct criteria that must be considered. Most HDMI connections will provide the greatest resolution and color space possible on a camera's output, however HD-SDI connections may be more limited due to the usage of a lesser standard. This assumes that the PTZ cameras have multiple video outputs and that they both operate at the same time, which isn't always the case.

While the HDMI output of a 4K PTZ camera may be capable of 4K 30P, the HD-SDI output is often limited to a 3G HD-SDI output of 1080 60P. Both outputs can be utilized at the same time, but only if they are configured to the same resolution and frame rate.

One advantage of utilizing a PTZ camera is that they are frequently IP-based cameras, which means you can transfer video over Ethernet using a variety of different protocols that vary depending on the PTZ camera. RTMP, RTSP, and RTP are well-known protocols, but NDI and SRT are newer and, in some ways, more ideal protocols for contemporary and future workflows.

NDI is a royalty-free IP video protocol created by NewTek that comes in two variants. NDI High Bandwidth (also known as Full NDI) features less compression, lower latency, and consumes more bandwidth, whereas NDI|HX is a high efficiency variant that employs H.264 or H.265/HEVC compression. NDI|HX is currently available in three flavors: NDI|HX, NDI|HX2, and NDI|HX3. Some PTZ cameras have NDI licenses, while others require a purchased update to enable NDI features.

Haivision's SRT is an open source technology that enhances video streaming performance on unstable networks. Missing packets can be recognized and a negative acknowledgment (NAK) issued to the sender using a delay buffer in both the sender encoder and the receiver decoder. When the NAK is received, the missing packet is resend and reassembled. When satellite or fiber connections are unavailable, SRT is a significantly less expensive method of sending video.

The key advantages of SRT include safe AES128 and AES256 encrypted streams, as well as simpler firewall bypassing through call and listener modes. SRT is suitable for video contribution, backhaul, bidirectional interview, and broadcast return feeds.

A USB output option that supports the webcam UVC protocol is available on several PTZ cameras. This can be an excellent approach to improve the production value and quality of footage that would otherwise be captured with a webcam during a live meeting.

Inputs

An inbuilt microphone or support for 3.5mm or XLR audio inputs are common PTZ camera audio inputs. Because the PTZ cameras I use lack inbuilt microphones, I usually utilize a soundboard to combine my audio sources. I seldom stream audio back to the PTZ cameras. However, I can add audio straight to my software or hardware video switcher.

POE is a power delivery protocol that uses ethernet to power the PTZ camera. To pump power into the ethernet wire, a POE switch is necessary. POE+ (Figure 6) or POE++ (Figure 6) are the two most prevalent standards required for POE cameras, depending on the amount of power required. An AC-to-DC power adaptor may also be used to power PTZ cameras.

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