Glossary
Quick definitions of the technical terms used throughout this documentation. If a term is missing, please let us know.
APC-R
APC-R is Middle Things' flagship gimbal-to-network adapter. It connects to a DJI RS-series gimbal and exposes both the gimbal — and any compatible Bluetooth-paired camera — to your network via Wi-Fi or Ethernet, so they can be controlled over IP from Middle Control. One APC-R drives one gimbal and one camera. The camera does not necessarily have to be paired through the APC-R's Bluetooth chip; it can also be controlled directly over the network or by the ATEM through SDI / HDMI for supported cameras. The APC-R connects to the gimbal through the APC-R Gimbal Adapter or the DJI Focus Wheel, using the CANBUS protocol.
APC-R Mini
APC-R Mini is a smaller, more modern, and lower-cost variant of the APC-R. It offers the same core IP-control functionality, including Bluetooth camera pairing, in a compact form factor that mounts directly onto the gimbal itself. Compared to the original APC-R, the micro-USB port has been replaced by USB-C, and the APC-R Mini also features a built-in tally light.
APC-R Mini Lite
APC-R Mini Lite is the entry-level model in the APC-R Mini family. It controls the gimbal only — no Bluetooth camera pairing, no built-in Wi-Fi chip, and no tally light. Network access is wired-Ethernet only. Otherwise, it is identical to the APC-R Mini.
ATEM
ATEM is Blackmagic Design's line of live production video switchers. ATEMs accept SDI/HDMI camera inputs, can issue camera control commands back over those signal lines (for Blackmagic cameras), and integrate with computers via Ethernet through ATEM Software Control or hardware control panels.
ATEM SDI
ATEM SDI refers to the SDI-based ATEM Mini series (ATEM SDI, ATEM SDI Pro ISO, ATEM SDI Extreme ISO). These are the SDI counterparts to the HDMI ATEM Mini models, intended for broadcast workflows where SDI cabling is preferred over HDMI.
CANBUS
CANBUS (Controller Area Network bus) is a robust serial network protocol originally designed for automotive applications. DJI RS-series gimbals expose CANBUS through the RSA port, which the APC-R uses to access advanced features — Position Presets, Focus Motor control, Remote Calibration, Sleep/Wake, and ActiveTrack — that aren't available over SBUS (defined below).
SBUS
SBUS is a single-wire serial protocol from the RC (radio-controlled) hobby world. Older DJI Ronin gimbals (Ronin-S, Ronin-SC, Ronin-2) accept SBUS for basic pan, tilt, and roll control. Advanced features such as Position Presets, calibration, and ActiveTrack are CANBUS-only.
RSA port
The RSA port is DJI's proprietary expansion port on the side of RS-series gimbals (RS2, RS3 Pro, RS4 Pro, RS5, etc.). It provides both power and data, and is the connection point for the DJI Focus Wheel, APC-R Mini, APC-R Mini Lite, and the APC-R Gimbal Adapter (for use with the older APC-R).
SRT
SRT (Secure Reliable Transport) is an open-source streaming protocol that delivers low-latency video over unpredictable IP networks. Middle Control uses SRT to carry the Live View video feed from supported cameras over the network.
RavenEye
RavenEye is DJI's wireless image transmission accessory for Ronin gimbals. It sends a low-latency 1080p video preview from the camera to a phone or laptop over Wi-Fi, and is mentioned in compatibility notes as an alternative wireless monitoring path.
M/E (Mix/Effects bus)
An M/E (Mix/Effects) bus is a self-contained mixing engine inside a video switcher. Each M/E has its own Program and Preview outputs and can layer keys, downstream effects, and sub-mixes. Larger ATEMs are sold as 1 M/E, 2 M/E, or 4 M/E models — the number of independent mixing engines available.
PTZ
PTZ stands for Pan, Tilt, Zoom — both a category of remotely-controllable cameras and a control concept. Middle Control turns any DJI-gimbal-mounted camera into a software PTZ rig, controllable from a joystick, gamepad, Stream Deck, or VISCA controller, in addition to natively supporting dedicated PTZ cameras.
BMPCC
BMPCC is community shorthand for "Blackmagic Pocket Cinema Camera." Models in this line include the Pocket Cinema Camera 4K (MFT mount), the 6K G1/G2 (EF mount), and the 6K Pro (EF mount).
MFT (Micro Four Thirds)
MFT (Micro Four Thirds) is a lens mount and sensor format jointly developed by Olympus and Panasonic. It is used on the Blackmagic Pocket Cinema Camera 4K, the Panasonic Lumix GH series, and the Blackmagic Micro Studio 4K cameras.
EF (Canon EF mount)
EF is Canon's classic SLR/DSLR lens mount. It is used on the Blackmagic Pocket Cinema Camera 6K series, the Blackmagic Cinema Camera 6K, and most Canon DSLR and Cinema EOS bodies. Cine zoom lenses such as the Canon CN-E 18-80 T4.4 use this mount.
VISCA
VISCA is Sony's PTZ camera control protocol. Originally designed for serial RS-232/RS-422 connections, it has been extended to VISCA over IP (UDP-based), now an industry standard for PTZ controllers. Middle Control Pro includes a VISCA over IP server, letting third-party VISCA controllers (Skaarhoj, AVMatrix, Zowietek, etc.) drive Middle Control.
DJI Focus Motor
A DJI Focus Motor is a small motorized accessory that clamps onto a lens and drives its focus or zoom ring. It connects to one of the USB-C ports of an RS-series gimbal. Three generations exist: the original DJI Focus Motor (compatible with RS2 and RS3 Pro), the DJI Focus Motor 2022 (designed for the RS3 Pro), and the DJI Focus Pro (for the DJI RS4 and later).
DJI Focus Wheel
The DJI Focus Wheel is a hand-wheel accessory that mounts to the side of an RS-series gimbal via the RSA port and exposes the gimbal's CANBUS. The APC-R uses the Focus Wheel (or the equivalent APC-R Gimbal Adapter) as a CANBUS bridge to access advanced gimbal features. Required for full-feature CANBUS control on RS3 Pro, RS4, RS4 Pro, and RS5. It is not required when using the APC-R Mini.
Middle Control
Middle Control is Middle Things' desktop application for macOS and Windows. It is the central control surface for connected gimbals, cameras, and integrations — issuing commands, managing presets, and synchronizing with ATEM switchers. The macOS and Windows apps share the same hardware and protocols but have a different feature set — some Pro features are macOS-only.
Middle Control Pro
Middle Control Pro is the paid, macOS-only tier of Middle Control. It adds Multi View, ATEM Link, Automations, Multi-Operator, Replicate Settings, Record Center, Video Output, and the VISCA over IP server. Direct IP camera control over Wi-Fi / Ethernet and Live View are in the free version. See the Downloads page for licensing details.
Middle Remote
Middle Remote is Middle Things' purpose-built physical PTZ controller using Make Pro X's modular tile system. It provides a high-quality joystick, precision rotary encoders, and OLED status displays for tactile camera and gimbal operation.
MakePro Glue
MakePro Glue is configuration software from Make Pro X used to set up Middle Remote and other modular control hardware in their ecosystem. It runs on macOS and Windows. Glue is only needed when the Middle Remote connects through Glue — a direct USB connection (or a Pro network connection) needs no Glue.
Bitfocus Companion
Bitfocus Companion is an open-source control surface server that lets devices like the Elgato Stream Deck trigger Middle Control actions — preset recall, record start/stop, camera switching, custom macros — through a button-based UI. Middle Things ships ready-to-use Companion button pages.
DHCP
DHCP (Dynamic Host Configuration Protocol) is the standard mechanism by which a router automatically assigns IP addresses to devices on a network. Most Middle Things workflows rely on DHCP — when an APC-R is connected to a router, it receives an IP automatically and Middle Control discovers it via Bonjour/mDNS without further configuration.