ST 2110 Output

SMPTE ST 2110 is the IP-based equivalent of SDI for professional video transport. In WATCHOUT, ST 2110 is one of the display output types alongside GPU, SDI, NDI®, and Virtual. Choosing ST 2110 routes the rendered display output through a Deltacast ST 2110 IP board in the Runner node, delivering uncompressed video as a multicast IP stream over Ethernet.

ST 2110 is the right choice when the receiving equipment — broadcast switchers, IP-based LED processors, or playout infrastructure — expects an IP stream rather than baseband SDI. It replaces one BNC per signal with one Ethernet cable that can carry many streams at once.

For the concepts behind ST 2110 and the per-node commissioning workflow (PTP, network ports, channel configuration), see ST 2110 Video Over IP and Setting Up ST 2110. This page covers the per-display configuration only.

Configuring an ST 2110 Display

To set up a display for ST 2110 output:

  1. Select the display in the Stage or Device list.
  2. In Device Properties → Output, set the Output Type to ST 2110.
  3. Assign the Channel number corresponding to the desired stream on the board (see Channel Assignment below).
  4. Set the Resolution and frame rate to match the receiver's expected stream format.

Channel Assignment

The Channel property is an index into the Deltacast VideoMaster SDK's output list on the Runner node, starting at 1. SDI and ST 2110 share the same VideoMaster channel namespace — channels are enumerated across all Deltacast boards on the node, not per board. With an 8-port SDI board and a 4-channel ST 2110 board in the same node, the SDI board might occupy channels 1–8 and the ST 2110 board channels 9–12. The exact ordering follows each card's PCIe address and depends on which PCIe slot the board is connected to.

For ST 2110 boards, the channel count per board reflects how many streams the board can handle simultaneously and is a property of the hardware. Enabling SMPTE 2022-7 Seamless Protection Switching (SPS) for redundancy does not change the channel count — the primary and secondary network ports together still represent one logical channel per stream.

Stream Properties

ST 2110 publishes the video as a multicast UDP flow. Three properties under Stream Properties define where the flow is sent:

  • Multicast Address — the IPv4 multicast group the video is published to. Must be a valid multicast address (224.0.0.0–239.255.255.255). Receivers join this group to subscribe to the stream.
  • Port — UDP port for the video flow (1–65535). Audio and metadata flows would use separate ports.
  • Time To Live (TTL) — maximum number of router hops the multicast packets may traverse before being dropped (1–255, default 128). A TTL of 1 keeps the stream on the local segment; higher values are required when receivers are reached through a router.

Coordinate addresses, ports, and TTL values with the rest of the ST 2110 facility (or the receiver's expected configuration) so each stream lands at the correct destination without colliding with other flows on the network.

SMPTE 2022-7 Redundancy (SPS)

ST 2022-7 Seamless Protection Switching (SPS) sends two identical copies of the stream over independent network paths. The receiver picks the first packet to arrive from either copy, so if one path drops packets — or fails entirely — the output stays clean. Configure the redundant stream under SPS Properties:

  • SPS Multicast Address — the multicast group for the redundant flow. Must differ from the primary Multicast Address — the producer panel rejects the entry otherwise with "SPS multicast address must differ from primary stream" — and should be routed over a physically separate network path.
  • SPS Port — UDP port for the redundant flow (1–65535).

The redundant flow carries the same encoded video as the primary; SPS does not change the channel count or per-stream bandwidth. Pair this with a second NIC on a separate physical network for genuine path redundancy — running both flows through the same switch defeats the purpose.

Capturing an SDP File

ST 2110 receivers are typically configured by reading an SDP (Session Description Protocol) file that describes the stream's addresses, ports, codec, frame rate, and colorimetry. Click Capture SDP as File in Device Properties to save the SDP describing this display's output.

The button is only clickable when the display is enabled, but capture also requires the output to be active on its Runner node. Producer pulls the SDP from the Runner that is actually producing the stream, so the Runner must be online and the stream must be live at the moment of capture. If the output is not currently running, the request fails and no SDP is saved — enable the display, confirm it is rendering on the node, and try again.

Hand the resulting SDP file to the receiver — broadcast switcher, IP-based LED processor, recorder, and so on — so it can subscribe to the stream without manual entry of every parameter. NMOS-based routing infrastructure typically handles SDP exchange automatically; see ST 2110 Video Over IP.

Color and Signal Settings

ST 2110 shares the Deltacast output pipeline with SDI, so the color choices are the same:

  • Color Depth — 8 or 10 bits per component.
  • Color Space — Rec. 601, Rec. 709, Rec. 2020, Rec. 2100 HLG, or Rec. 2100 PQ. Default is Rec. 709.

ST 2110 output is always progressive. There is no interlaced option (unlike SDI).

Max Quality Mode

The Render with maximum quality toggle uses 16-bit color for compositing. It only has an effect on 8-bit displays — higher bit-depth outputs already use higher precision for compositing. Disable it on integrated GPUs to reduce pixel bandwidth when the extra precision is not needed.

Synchronization

Where SDI uses analog genlock to align frame timing across outputs, ST 2110 uses PTP (Precision Time Protocol) as a shared network clock. All ST 2110 senders and receivers on the network lock to the same PTP leader (often called the PTP grandmaster), and frame-timing alignment is a property of the network rather than a per-display setting.

WATCHOUT is PTP follower-only. It inherits its timing from the PTP leader configured during node commissioning, and there is no per-display sync toggle for ST 2110 output.

Frame Delay

The Delay Frames setting (0–10 frames) adds a configurable output delay to the display. Each frame of delay adds one additional frame buffer to the rendering pipeline before the pixels are sent to the ST 2110 output.

This is useful for compensating processing latency in downstream equipment. For example, if a downstream device introduces a fixed two-frame delay, add a matching delay to other displays in the system so all outputs appear time-aligned at the receiver.

Hardware Requirements

ST 2110 output in WATCHOUT requires a Deltacast ST 2110 IP board (such as the DELTA-IP series) installed in the Runner node, paired with a GPU that supports zero-copy transfers from the render pipeline into the card.

Key requirements:

  • Deltacast ST 2110 IP board with output capability.
  • Deltacast drivers installed on the Runner node. The driver package ships with the runtime libraries WATCHOUT needs — no separate SDK install is required.
  • Professional NVIDIA GPU with GPUDirect support (Quadro / RTX A-series / RTX Ada Generation, etc.). GPUDirect enables direct-DMA transfers between the GPU framebuffer and the Deltacast board, avoiding a round-trip through system memory. Consumer NVIDIA cards and non-NVIDIA GPUs do not support GPUDirect and cannot drive ST 2110 output.
  • PTP leader reachable from the node (a dedicated PTP appliance, a PTP-capable switch, or another professional device).
  • Switch with IGMP snooping and PTP pass-through to prevent multicast flooding.
  • NIC matching the board's link speed (typically 25 GbE) for the primary stream port, and optionally a second port at the same speed for SPS redundancy.

If the Deltacast IP board is not detected, the ST 2110 Interfaces dialog shows "No ST 2110 interfaces found" and no streams are published. See Setting Up ST 2110 for board commissioning.

Per-node ST 2110 setup (PTP and port assignment) is done once in the ST 2110 Interfaces dialog, not on each display. Channels themselves are a fixed property of the installed hardware — see Channel Assignment.

NDI® is a registered trademark of Vizrt NDI AB.

Previous Next