The Shift from SDI to IP in Broadcast — What It Means for the Industry
The Foundation of Broadcast: SDI
For over 30 years, SDI (Serial Digital Interface) was the gold standard for professional video transport. Defined by the SMPTE 259M standard in 1989, SDI carries uncompressed digital video over coaxial cable — reliably, at low latency, with no compression artefacts.
Broadcast facilities worldwide were built on SDI infrastructure:
- Camera to vision mixer via SDI
- Vision mixer to playout server via SDI
- Playout server to transmitter via SDI
Every piece of equipment had BNC connectors. Engineers knew exactly what they were dealing with. SDI was deterministic, simple, and rock solid.
So why is the industry moving away from it?
The Limitations of SDI
Distance and Cabling Costs
SDI runs reliably over coaxial cable up to around 100 metres for HD signals. Longer runs require expensive equalisation equipment. Large facilities — stadiums, arenas, multi-building campuses — need extensive cabling infrastructure that is costly to install and maintain.
Fixed Point-to-Point Routing
SDI is inherently point-to-point. To route a signal from A to B to C, you need physical router hardware with dedicated crosspoints. Reconfiguring signal paths requires physical changes or expensive SDI routing switchers.
Limited Scalability
Adding new sources or destinations to an SDI infrastructure means running new cables and adding router capacity. This is expensive and time-consuming.
No Native IT Integration
SDI lives in its own world. It doesn't integrate natively with IT networks, cloud services, or software-based workflows. As production has moved toward software and the cloud, SDI has become an island.
4K and Beyond
While HD-SDI handles 1080p reliably, 4K (UHD) required new standards — 3G-SDI, 6G-SDI, 12G-SDI — each demanding more expensive cables and equipment. The cost curve for SDI at higher resolutions becomes steep quickly.
Enter IP Video
IP-based video transport replaces coaxial SDI cables with standard Ethernet networks. Video signals are packetised and sent over the same network infrastructure used for IT data.
Key standards driving IP broadcast adoption:
SMPTE ST 2110
The most important standard for professional IP broadcast. ST 2110 separates video, audio, and ancillary data into independent streams, each carried over IP. It supports uncompressed video at the highest quality levels — making it a true SDI replacement for live production.
SMPTE ST 2022
An earlier standard using compressed video over IP. ST 2022-6 carries SDI signals encapsulated in IP, acting as a bridge between SDI and IP worlds.
NDI (Network Device Interface)
Developed by NewTek (now Vizrt), NDI is a compressed IP video protocol that runs over standard Gigabit Ethernet. While not a broadcast standard in the SMPTE sense, NDI has become hugely popular for production workflows, remote cameras, and — critically — software playout systems like InstaPlayout.
SRT and RTMP
For contribution and distribution over the public internet, SRT (Secure Reliable Transport) and RTMP carry compressed video streams to streaming platforms, CDNs, and remote facilities.
UDP (User Datagram Protocol)
UDP is the transport layer protocol that underlies much of IP video delivery. Unlike TCP, UDP does not guarantee packet delivery or ordering — instead it prioritises speed and low latency.
InstaPlayout supports UDP output natively, making it a direct replacement for hardware encoders in IPTV headend workflows.
DVB (Digital Video Broadcasting)
DVB is a family of internationally adopted standards for digital television transmission. Originally developed for satellite (DVB-S), cable (DVB-C), and terrestrial (DVB-T) broadcast, DVB defines how video is encoded, multiplexed, and transmitted to end viewers.
Why the Industry Is Making the Switch
Cost Reduction
Standard Ethernet switches and Cat6/fibre infrastructure are dramatically cheaper than SDI routing infrastructure.
Flexibility and Scalability
IP networks are inherently flexible. Adding a new source or destination is a software configuration change, not a cable run.
Remote Production
IP video can travel over the internet. This opened the door to REMI (Remote Integration Model) production, where cameras at a sports venue feed back to a central facility over IP, eliminating the need for a full outside broadcast truck.
Cloud Integration
IP video is cloud-native. Signals can be ingested directly into cloud platforms for processing, storage, and distribution.
Software-Defined Everything
When video is just data on an Ethernet network, software can do what hardware used to. A software playout system running on a standard PC can ingest, process, schedule, and output professional video — replacing racks of dedicated hardware.
SDI vs IP: Key Comparison
| Feature | SDI | IP (ST 2110 / NDI) | |---|---|---| | Cable type | Coaxial (BNC) | Ethernet (Cat6 / Fibre) | | Distance | ~100m (HD) | Unlimited (with switching) | | Routing | Hardware router | Software-defined | | Scalability | Expensive | Highly scalable | | Remote production | Not native | Native | | Cloud integration | No | Yes | | Latency | Very low | Very low (with proper QoS) | | Cost (large scale) | High | Lower | | Complexity | Low | Medium–High | | Software playout | Limited | Native |
Conclusion
The shift from SDI to IP is not just a technical upgrade — it's a fundamental reimagining of what broadcast infrastructure means. IP makes broadcast more flexible, more scalable, more affordable, and more connected to the rest of the digital world.
For independent broadcasters, this shift is the single biggest enabler of the last decade. Combined with software playout tools like InstaPlayout, it means that professional-quality 24/7 television is no longer the exclusive domain of well-funded broadcasters. Anyone with the right software and a reliable internet connection can broadcast to the world.