Glossary
10 Gigabit Ethernet (10GbE)
10GbE is a data transfer standard used for network infrastructure. DisplayNet uses SDVoE technology to leverage 10GbE for uncompressed high resolution AV signal distribution applications. Due to high bandwidth requirements, DVIGear strongly recommends the use of CAT-6A F/UTP cables.
1 Gigabit Ethernet (1GbE)
1GbE is a data transfer standard used to provide high speed connectivity for end-users. Every DisplayNet device is equipped with a 1GbE LAN port which provides 10/100/1000 Mbps network connectivity at each and every endpoint.
Adaptive Clock Resynchronization (ACR)
Adaptive Clock Resynchronization is an SDVoE-exclusive technology used to ensure synchronous signal distribution and to reduce the bandwidth used by HDMI video signals. The HDMI protocol is reliant on a synchronous connection. IP networking, however, is an asynchronous medium. Historically, AV-over-IP solutions have required framebuffers and re-clocking to counteract this, this results in increased latency and frame ordering issues. ACR works by regenerating the original source clock at the receiving endpoint, resulting in an output signal that is time-locked to the original source with mere microseconds of latency. This technology allows DisplayNet to route uncompressed 4K HDMI video with zero frame latency and no framebuffer in genlocked mode, using standard 10GbE network switches.
Application Programming Interface (API)
The DisplayNet API is the software interface layer between the control equipment / software and the DisplayNet endpoints being controlled. The API Manual contains the instructions and command set necessary to develop client control applications for DisplayNet devices. The API makes it easy to integrate DisplayNet into third-party control environments. The API Engine is the DisplayNet server software component that makes the API available to DisplayNet Manager and control devices, converting API commands to UDP commands and dispatching them to devices across the network.
Automatic Private IP Addressing (APIPA)
The APIPA protocol enables network devices to automatically obtain network settings without the use of a DHCP server. Addresses are assigned in the 169.254.X.X range with a subnet mask of 255.255.0.0. The Address Resolution Protocol (ARP) is used to ensure that there are no IP address conflicts. The APIPA scheme is widely adopted in many platforms such as Windows and Linux. By default, DisplayNet endpoints and DisplayNet Server use APIPA in the event there is no DHCP server connected.
Bitstream Audio
Bitstream Audio refers to various compressed digital audio formats that may be carried over HDMI, such as Dolby Digital TrueHD and DTS-HD. These formats allow for higher bitrates and more channels than LPCM audio over the same connection. DisplayNet supports pass-through of embedded high bitrate (HBR) audio formats with up to 24-bit depth and 192 kHz sampling rate.
Bursty Traffic
Bursty traffic refers to network data transmission patterns where traffic occurs in irregular, short bursts of high activity followed by periods of low or no activity. This is characteristic of typical IT network traffic, where data requests and transfers happen intermittently rather than continuously. Unlike bursty IT traffic, DisplayNet video streams transmit at constant, sustained bandwidth, requiring dedicated bandwidth allocation and careful network design to prevent oversubscription.
Category 6 Augmented (CAT-6A)
CAT-6A Ethernet cabling is specifically designed to enable 10GbE signals to be extended up to 330 ft. (100 meters) over copper cable. Compared to CAT6, the amount of crosstalk is reduced, especially at higher frequencies. DVIGear strongly recommends using CAT-6A F/UTP cable for all of the copper 10GbE connections in a DisplayNet system.
Coder / Decoder (Codec)
A codec is a device or computer program used to encode or decode audio and video. DisplayNet uses hardware-based SDVoE codecs: transmitters encode HDMI signals into IP packets while receivers decode the packets back to HDMI output. Unlike traditional compression codecs, DisplayNet's SDVoE codec preserves zero-latency, uncompressed video quality.
Display Mode
The Display Mode determines how the receiver displays transmitted content. DisplayNet receivers support four display modes: Genlocked Mode (zero frame latency), Fast Switched Mode (seamless switching), Genlock Scaling Mode (low-latency with scaling), and Wall Mode (used exclusively for video walls).
DisplayNet Manager Software
DisplayNet Manager software is a web-based application that provides a user interface for controlling and managing DisplayNet systems. It interfaces with the DisplayNet Server to control and manage the entire system. DisplayNet Manager software includes tools to route signals, configure device settings, build wall configurations, perform EDID management, save presets, and view DisplayNet API commands.
DisplayNet Server
DisplayNet Server (capital S) is DVIGear's hardware product - a 1U, half-rack width, fanless Linux server that serves as the central control hub for DisplayNet systems. In this manual, "DisplayNet server" (lowercase s) refers to the software component that runs on the DisplayNet Server hardware. The DisplayNet server software provides the API Engine, which interfaces with the DisplayNet API and endpoints, converting API commands to SDVoE commands and dispatching them across the network. DisplayNet Server hardware comes pre-installed with the DisplayNet server software and DisplayNet Manager web application.
Dynamic Host Configuration Protocol (DHCP)
DHCP facilitates the automatic assignment of IP addresses to every device linked to the network. The duration of these IP addresses can vary, depending on the configurations of both the devices and the DHCP server. Leases may be either permanent or temporary based on these settings.
Endpoint
An endpoint is any DisplayNet device connected to the network, including transmitters, receivers, and transceivers. Each endpoint is identified by its MAC address and can be controlled via the DisplayNet API.
Extended Display Identification Data (EDID)
EDID is a small data file stored in virtually every modern TV, monitor and display device. This file contains information about the display’s capabilities, such as its supported resolutions, refresh rates, color space, type of display, manufacturer, serial number, etc. After connecting a display to a source device, the source reads and saves the EDID in order to determine the most suitable display parameters (e.g. resolution and refresh rate).
Fast Leave
An option available in many 10GbE network switches allowing receivers to unsubscribe from one multicast group and join another very quickly. This option must be available and enabled in the 10GbE network switch in order to fully support seamless switching in Fast Switched Mode.
Fast Switched Mode
Fast Switched Mode is a display mode on the receiver used to enable seamless switching between different sources. To enable Fast Switched Mode, the DisplayNet receivers include a frame buffer that buffers a single frame of video. When switching between two sources with the same video characteristics, the switch will be seamless as the switchover occurs within the time period in which the frame stored in the frame buffer is displayed onscreen. To fully support seamless switching even at high resolutions, the Fast Leave option must be activated in the network switch.
Genlocked Mode
Genlocked Mode is a display mode on the receiver that ensures low latency and synchronization between displays. When a receiver is set to Genlocked Mode, the HDMI input of the display connected to the RX is synchronized directly to the HDMI source. Furthermore, when multiple RX devices in Genlocked Mode are joined to a single TX, all displays are genlocked to the same source, allowing for precise synchronization between identical displays. In Genlocked Mode, there is a maximum of 30 microseconds total end-to-end latency (Zero Frame Delay).
Genlock Scaling Mode
Genlock Scaling Mode is a display mode on the receiver that ensures low latency and synchronization between displays, while allowing for a scaled output signal. Genlock Scaling Mode works similarly to Genlocked Mode in that it bypasses the framebuffer and synchronizes the destination display with the source signal; however, it differs in that the signal passes through the scaler before it goes out to the display. When multiple RX devices in Genlock Scaling Mode are joined to a single TX, all displays are genlocked to the same source, allowing for precise synchronization between identical displays. Genlock Scaling Mode has about 3 milliseconds total end-to-end latency, or approximately one-quarter of one frame at 60 frames per second.
HID endpoint (Human Interface Device)
HID endpoints allow transmission of USB Human Interface Device signals (keyboard, mouse, touchpad) over the DisplayNet network with instant switching capability. This enables KVM-style control where input devices connected to one location can control computers connected elsewhere in the DisplayNet system. DisplayNet also supports USB 2.0 endpoints for KVM functionality with virtual hub support, though without instant switching.
High-bandwidth Digital Content Protection (HDCP)
HDCP is a key-based authentication technology implemented to prevent rights protected content from being transmitted to non-protected devices. The HDCP authentication protocol allows the source device to determine whether the destination device is compliant. If the key from the destination is accepted by the source, the source will transmit the signal, but if not, then no signal will be transmitted. This process is repeated every 2 seconds to ensure content protection is maintained at all times. DisplayNet is fully HDCP 2.2 compliant from source-to-display.
High-Definition Multimedia Interface (HDMI)
HDMI is an AV standard for transmitting uncompressed audio and video content from one device to another. It also includes support for HDCP encryption. This standard was originally based on the DVI standard and continues to be used globally today. The DN-300 and DN-200 series both support v2.0 of the HDMI standard.
Internet Group Management Protocol (IGMP) Snooping
IGMP snooping allows a network switch to create multicast groups to which receivers may subscribe. In a DisplayNet system, when a transmitter connects to the switch, it is assigned a multicast address and begins sending the video stream to that address. One or more receivers may then subscribe to the video feed from the transmitter. If IGMP snooping is not properly configured, multicast packets will be broadcast to all of the ports on the switch, which will cause network flooding.
Input Lag
The total amount of time it takes for a display to process and display the signal received at its input. This is display dependent. Input Lag is separate from Response Time, which refers only to the responsiveness of the panel inside the display, rather than the total speed of the video processing pipeline within the display. For time-critical applications, selecting displays with minimal input lag is highly recommended.
Internet Protocol (IP) Address
The IP address is a unique number assigned to each device on a network to allow routing between it and other devices. DisplayNet devices use IPv4 addressing and do not support IPv6.
Infrared (IR)
Data can be transferred using infra-red wavelengths of light. This technology is commonly used for remote control devices. DisplayNet supports bidirectional IR communications.
KVM
KVM stands for Keyboard, Video, and Mouse - a system that allows remote control of a computer. DisplayNet supports KVM functionality through both HID endpoints (with instant switching) and USB 2.0 endpoints (with virtual hub support), enabling centralized control of distributed computing resources.
Linear Pulse-Code Modulation (LPCM)
LPCM is an uncompressed digital audio format used for many digital audio applications, such as HDMI and Compact Discs. DisplayNet supports the routing of up to 8 channels of HDMI embedded LPCM digital audio with up to 24-bit depth and a 192 kHz sampling rate.
Media Access Control (MAC) Address
A MAC Address is a unique identifier assigned to every Ethernet device. Unlike IP addresses, MAC addresses are assigned by the manufacturer upon manufacture, and are generally non-changeable. The MAC Address of each DisplayNet endpoint is used by the API Engine to identify individual devices as well as send data and commands to them, regardless of their IP configuration. Additionally, the DisplayNet API uses the MAC Address as the "device_id" in order to send and retrieve data from a particular device (see the DisplayNet API Manual for further information).
Multicast
Multicasting enables multiple devices to subscribe to the data stream from a single device. The transmitting device is assigned a multicast address by the network, and the receiving devices may join that multicast group to receive the stream from the transmitting device. Proper IGMP Snooping configuration is required to prevent network flooding.
Multiview
Multiview is an application in which the DN-200 and DN-300 series receivers simultaneously display multiple video streams on the destination display. The receiver does this by joining multiple transmitter multicast groups at once. Up to 32 streams are supported, as long as the total bandwidth of all subscribed streams does not exceed 10 Gbps. To aid with this, these transmitters have two separate HDMI streams, Stream 0 is the original HDMI source stream, and Stream 1, if enabled, has a scaled-down stream. Multiviews use Stream 1 to pull the appropriate resolution video for the window in which the stream is assigned. Stream 1 also has an optional framerate converter available that can cut the framerate of the source stream in half to save bandwidth.
Non-blocking Switch
A Non-blocking Switch enables every 10GbE port to operate simultaneously at full duplex bandwidth. This feature is required for DisplayNet systems because unlike typical IT network traffic that occurs in irregular bursts, DisplayNet transmits video at constant full bandwidth, requiring dedicated bandwidth allocation for each video stream.
Oversubscription
Oversubscription occurs when a network, port or switch has more incoming traffic than outgoing bandwidth available. DisplayNet systems require careful network design to avoid oversubscription because video streams transmit at constant full bandwidth, unlike typical IT traffic that occurs in irregular bursts with periods of low activity. When properly configured, DisplayNet systems should not experience any oversubscription issues.
Receiver (RX)
A DisplayNet Receiver (RX or decoder) subscribes to the multicast signal output by the transmitter, decodes it, and outputs it to the display. Receivers support multiple display modes: Genlocked Mode provides zero frame latency (maximum of a 30 microsecond delay), Fast Switched Mode supports seamless switching, and Wall Mode is used for video wall applications. Receivers that are part of an active video wall must use Wall Mode; HDMI audio output is not supported in this configuration.
Small Form-factor Pluggable transceiver (SFP+)
DN-200 and DN-300 transmitters and receivers include a Small Form-factor Pluggable (SFP+) interface slot. This industry-standard slot is used with modular transceivers to enable 10GbE communication over fiber-optic cables. This allows for very long extension distances of up to 18 miles (30 kilometers), when used with the recommended Fiber Optic Media for the transceiver in use.
Software Defined Video over Ethernet (SDVoE)
Software Defined Video over Ethernet (SDVoE) is the 10GbE IP-based standardized platform that DisplayNet uses to encode, decode, and route signals. SDVoE employs Adaptive Clock Resynchronization (ACR) to encode HDMI video, rather than traditional compression, allowing for transmission of AV signals with zero frame latency and zero quality loss. Unlike typical network traffic that transmits in irregular bursts, SDVoE video streams require constant, dedicated bandwidth allocation throughout the entire transmission.
Software Defined Video over Ethernet (SDVoE) Alliance
The Software Defined Video over Ethernet (SDVoE) Alliance is a nonprofit consortium of technology providers collaborating to standardize the adoption of Ethernet to transport AV signals in professional AV environments, and to create an ecosystem around SDVoE technology allowing software to define AV applications. DisplayNet is built on the SDVoE technology platform.
Subnet Mask
A subnet mask is a 32-bit number that defines the network and host portions of an IP address range. All DisplayNet devices must be on the same subnet to function properly.
Synchronous Signal
Whereas Ethernet is an asynchronous type of signal, video and audio data are traditionally synchronous signals. The sequence and rate at which the data is delivered must be maintained from end-to-end. If the sequence or rate are compromised, signal problems are likely to occur. DisplayNet utilizes SDVoE technology called Adaptive Clock Resynchronization to guarantee synchronous data delivery and to genlock displays to sources.
Telnet
Telnet is a common network protocol that allows for bidirectional text communication. Historically used with terminals, telnet is commonly used as a control protocol in professional AV control systems. To support integration with third-party control systems, DisplayNet accepts DisplayNet API commands over telnet on port 6980 of the DisplayNet Server.
TMDS Synchronization
Transition Minimized Differential Signaling (TMDS) synchronization maintains accurate alignment of data in HDMI and DVI interfaces. DisplayNet preserves TMDS synchronization throughout the SDVoE transmission path, ensuring digital video signal integrity from source to display.
Transmission Control Protocol (TCP)
TCP is a network transmission standard for reliable data delivery. Every packet will be delivered in the correct order, at the cost of network overhead and latency.
Transmitter (TX)
A DisplayNet Transmitter (TX or Encoder) accepts multiple source signals including HDMI (with embedded audio and HDCP), analog stereo audio, bidirectional IR, RS-232, and 1GbE Ethernet. These input signals are packetized and distributed to receiving endpoints with an off-the-shelf 10GbE network switch.
Transceiver (TRX)
A DisplayNet Transceiver (TRX) is a versatile endpoint capable of simultaneous transmit and receive operations, allowing it to function as both a Transmitter and Receiver at the same time. This provides maximum flexibility in system design, enabling bidirectional AV signal routing through a single device.
User Datagram Protocol (UDP)
UDP is a network transmission standard that minimizes the amount of overhead required to transfer information. While there is reduced latency using this method, potential drawbacks include possible loss of data, duplication of data, as well as data arriving out of sequence. Although DisplayNet uses UDP for AV distribution, it is able to mitigate these issues using ACR, an SDVoE standard technology which resolves many common UDP issues when working with real-time AV traffic.
Unicast
Unicast traffic is network traffic between two individual devices. In a DisplayNet system, most RS-232 and IR communication is unicast.
Wall Mode
Wall Mode is the receiver Display Mode used in video walls. In Wall Mode, all receivers assigned to a wall are subscribed to the same multicast source group and are assigned a segment of video relevant to the receiver's position in the video wall. The receiver crops the source signal to the assigned video segment, and then pushes the signal to the framebuffer, where the cropped signal is synchronized to the adjacent displays using per-row delay. Finally, the signal is sent to the scaler, which scales the synchronized output to the native resolution of the destination monitor. This mode allows for tear-free, low-latency video wall operation with standard displays. As the framebuffer in each receiver is being used to resynchronize input signals, fast switching is not available in Wall Mode.