ST 2110 Source Operator #

Authors: Oliver Cleveley-Jones (XRlabs)
Supported platforms: x86_64, aarch64
Language: C++, Python
Last modified: March 10, 2026
Latest version: 1.0.0
Minimum Holoscan SDK version: 3.7.0
Tested Holoscan SDK versions: 3.7.0, 3.10.0, 3.11.0
Contribution metric: Level 2 - Trusted

ST 2110 Source

The ST 2110 Source operator receives SMPTE ST 2110-20 uncompressed video streams over IP networks. This operator is designed for professional broadcast and media production workflows requiring video ingestion from ST 2110-compliant sources.

Overview#

SMPTE ST 2110 is a suite of standards for the transmission of professional media over managed IP networks. ST 2110-20 specifically defines the transport of uncompressed video using RTP (Real-time Transport Protocol). This operator:

Receives ST 2110-20 RTP packets via Linux UDP sockets
Parses RTP and ST 2110-20 headers for frame reassembly
Reassembles packets into complete video frames using line number/offset addressing
Provides CUDA kernels for 10-bit YCbCr to RGBA/NV12 conversion
Supports multiple simultaneous output formats
Compatible with both x86_64 and aarch64 (ARM64) platforms including NVIDIA Thor AGX

Architecture#

The operator uses a triple-buffer architecture with CUDA pinned memory for efficient CPU-to-GPU transfer:

UDP Socket (multicast)
        │
        ▼
   recvmmsg() batch receive
        │
        ▼
   RTP/ST2110 header parsing
        │
        ▼
   Triple-buffer (pinned memory)
   [Assembling] [Complete] [Complete]
        │
        ▼
   cudaMemcpyAsync (H2D)
        │
        ├──► raw_output (YCbCr-4:2:2-10bit)
        │
        ├──► CUDA kernel ──► rgba_output (RGBA 8-bit)
        │
        └──► CUDA kernel ──► nv12_output (NV12 8-bit)

Output Ports#

The operator provides three output ports:

Port	Format	Description
`raw_output`	YCbCr-4:2:2-10bit	Raw ST 2110-20 frame data (always emitted)
`rgba_output`	RGBA 8-bit	Converted frame for visualization (optional)
`nv12_output`	NV12 8-bit	Converted frame for video encoding (optional)

Parameters#

Parameter	Type	Description	Default
`multicast_address`	string	Multicast IP address for ST 2110 stream	"239.0.0.1"
`port`	uint16_t	UDP port for ST 2110 stream	5004
`interface_name`	string	Linux network interface name (e.g., "mgbe0_0", "eth0")	"eth0"
`width`	uint32_t	Width of the video stream in pixels	1920
`height`	uint32_t	Height of the video stream in pixels	1080
`framerate`	uint32_t	Expected frame rate of the video stream	60
`stream_format`	string	Input format: "YCbCr-4:2:2-10bit", "YCbCr-4:2:2-8bit", "RGBA-8bit"	"YCbCr-4:2:2-10bit"
`enable_rgba_output`	bool	Enable RGBA conversion and emission	false
`enable_nv12_output`	bool	Enable NV12 conversion and emission	false
`batch_size`	uint32_t	Number of packets to receive per compute() call	1000
`max_packet_size`	uint16_t	Maximum ST 2110 packet size in bytes	1514

Requirements#

Hardware#

CUDA-capable NVIDIA GPU
Network interface with multicast support
ST 2110-compliant video source (e.g., Blackmagic Design equipment)

Software#

Holoscan SDK 3.7.0 or later
CUDA Toolkit 12.x or later
Linux with multicast routing configured

Usage Examples#

Python Example#

from holoscan.core import Application
from holoscan.operators import HolovizOp
from holohub.st2110_source import ST2110SourceOp

class ST2110App(Application):
    def compose(self):
        # Create ST 2110 source operator with RGBA output enabled
        source = ST2110SourceOp(
            self,
            name="st2110_source",
            multicast_address="239.255.66.60",
            port=16388,
            interface_name="mgbe0_0",
            width=1920,
            height=1080,
            framerate=50,
            stream_format="YCbCr-4:2:2-10bit",
            enable_rgba_output=True
        )

        # Visualize received video
        visualizer = HolovizOp(
            self,
            name="visualizer",
            width=1920,
            height=1080
        )

        # Connect RGBA output to visualizer
        self.add_flow(source, visualizer, {("rgba_output", "receivers")})

if __name__ == "__main__":
    app = ST2110App()
    app.run()

C++ Example#

#include "holoscan/holoscan.hpp"
#include "st2110_source.hpp"

class ST2110App : public holoscan::Application {
 public:
  void compose() override {
    using namespace holoscan;

    auto source = make_operator<ops::ST2110SourceOp>(
        "st2110_source",
        Arg("multicast_address", "239.255.66.60"),
        Arg("port", static_cast<uint16_t>(16388)),
        Arg("interface_name", "mgbe0_0"),
        Arg("width", 1920u),
        Arg("height", 1080u),
        Arg("framerate", 50u),
        Arg("stream_format", "YCbCr-4:2:2-10bit"),
        Arg("enable_rgba_output", true));

    auto visualizer = make_operator<ops::HolovizOp>(
        "visualizer",
        Arg("width", 1920),
        Arg("height", 1080));

    add_flow(source, visualizer, ('rgba_output', 'receivers'));
  }
};

int main() {
  auto app = holoscan::make_application<ST2110App>();
  app->run();
  return 0;
}

Building#

To build the operator:

./holohub build st2110_source

To build with Python bindings:

./holohub build st2110_source --configure-args "-DHOLOHUB_BUILD_PYTHON=ON"

Network Configuration#

System Configuration#

Increase the socket buffer size for high-bandwidth streams:

# Temporary (until reboot)
sudo sysctl -w net.core.rmem_max=268435456
sudo sysctl -w net.core.rmem_default=268435456

# Permanent (add to /etc/sysctl.conf)
net.core.rmem_max=268435456
net.core.rmem_default=268435456

Multicast Routing#

Ensure multicast traffic is routed to the correct interface:

# Add multicast route for your interface
sudo ip route add 239.0.0.0/8 dev mgbe0_0

# Verify multicast group membership
ip maddr show dev mgbe0_0

Supported Video Formats#

The operator supports ST 2110-20 uncompressed video at various resolutions:

720p (1280x720)
1080p/1080i (1920x1080)
2K (2048x1080)
UHD/4K (3840x2160, 4096x2160)

Supported input formats:

YCbCr-4:2:2-10bit: 2.5 bytes per pixel (default, common for broadcast)
YCbCr-4:2:2-8bit: 2 bytes per pixel
RGBA-8bit: 4 bytes per pixel

Troubleshooting#

No packets received#

Verify multicast address and port match your ST 2110 source
Check interface name is correct (ip link show)
Ensure multicast routing is configured
Check firewall allows UDP traffic: sudo ufw allow 5004/udp

Packet drops / frame tearing#

Increase socket buffer size (see Network Configuration)
Reduce other network traffic on the interface
Check CPU load - ensure sufficient cores available

Color issues#

Verify stream_format matches your source (10-bit vs 8-bit)
Check source colorimetry settings (BT.709 assumed)

Platform Support#

x86_64: Full support
aarch64 (ARM64): Full support including NVIDIA Thor AGX with MGBE

References#

SMPTE ST 2110-20:2017 - Uncompressed Video
SMPTE ST 2110-21:2017 - Traffic Shaping and Delivery Timing
Holoscan SDK Documentation

API Reference#

Python#

`ST2110SourceOp`#

Constructor Parameters#

Parameter	Type	Required	Description
`fragment`	`Fragment`	Required	The fragment that the operator belongs to.
`multicast_address`	`str`	Optional	Multicast IP address for ST 2110 stream (e.g., "239.255.66.60"). Default value is `"239.0.0.1"`.
`port`	`int`	Optional	UDP port for ST 2110 stream. Default value is `5004`.
`interface_name`	`str`	Optional	Linux network interface name (e.g., "mgbe0_0", "eth0"). Default value is `"eth0"`.
`width`	`int`	Optional	Width of the video stream in pixels. Default value is `1920`.
`height`	`int`	Optional	Height of the video stream in pixels. Default value is `1080`.
`framerate`	`int`	Optional	Expected frame rate of the video stream. Default value is `60`.
`stream_format`	`str`	Optional	Input stream format. Supported: "YCbCr-4:2:2-10bit", "YCbCr-4:2:2-8bit", "RGBA-8bit". Default value is `"YCbCr-4:2:2-10bit"`.
`enable_rgba_output`	`bool`	Optional	Enable RGBA conversion and emission on rgba_output port. Default value is `False`.
`enable_nv12_output`	`bool`	Optional	Enable NV12 conversion and emission on nv12_output port. Default value is `False`.
`batch_size`	`int`	Optional	Number of packets to receive per compute() call. Default value is `1000`.
`max_packet_size`	`int`	Optional	Maximum size of ST 2110 packets in bytes. Default value is `1514`.
`rtp_header_size`	`int`	Optional	Size of RTP header in bytes. Default value is `12`.
`name`	`str`	Optional	The name of the operator. Default value is `"st2110_source"`.

ST 2110 Source Operator#