Every production eventually outgrows HDMI. The cables are too short. The connectors pull out during live events. The distance between cameras and the production area exceeds HDMI’s limits. At that point, you face a choice: SDI or NDI.
We use both in our production workflows — SDI for camera acquisition in large venues, NDI for distributing video between computers and rooms. This guide explains when each makes sense, how they compare on every metric that matters, and how to build a hybrid setup that uses the strengths of both.
What Are NDI and SDI?
SDI (Serial Digital Interface)
SDI is the broadcast industry’s standard for moving video over physical cables. Developed in 1989 and refined through 30+ years of broadcast use. Video travels over dedicated coaxial cables with BNC connectors that lock in place.
- Dedicated physical connection
- Zero latency
- BNC connectors lock (no accidental disconnect)
- No network required
- Proven in broadcast for 30+ years
NDI (Network Device Interface)
NDI is NewTek’s (now Vizrt’s) protocol for sending video over standard IP networks. Released in 2015 and rapidly adopted in corporate, church, and live production. Video travels over ethernet cables using your existing network infrastructure.
- Uses existing ethernet network
- Auto-discovery (sources appear automatically)
- Software-based routing (no hardware router)
- Unlimited simultaneous receivers
- PoE (Power over Ethernet) cameras available
Head-to-Head Comparison
| Feature | NDI | SDI |
|---|---|---|
| Full Name | Network Device Interface | Serial Digital Interface |
| Signal Transport | IP network (Ethernet) | Dedicated coaxial cable (BNC) |
| Cable Type | Cat5e/Cat6 Ethernet | RG-6 or Belden 1694A coaxial |
| Max Cable Distance | 300+ feet (network dependent) | 300 feet (12G-SDI), 1,000+ feet (3G-SDI) |
| Latency | 2-4 frames (Full NDI) / 4-8 frames (NDI|HX) | Effectively zero |
| Bandwidth per 1080p60 Stream | ~125 Mbps (Full NDI) / ~12 Mbps (NDI|HX) | ~1.5 Gbps (uncompressed) |
| Resolution Support | Up to 4K (Full NDI 5.x) | Up to 8K (12G-SDI quad-link) |
| Discovery | Auto-discovery on network (mDNS) | Point-to-point only |
| Routing | Software-based (NDI Studio Monitor, vMix, OBS) | Hardware routers ($500-$50,000+) |
| Cable Cost (100ft) | $20-40 (Cat6) | $40-80 (RG-6) or $80-150 (Belden 1694A) |
| Infrastructure Required | Managed gigabit switch ($150-$400) | Direct cables or SDI router |
| Power over Cable | Yes (PoE cameras available) | No (separate power required) |
| Reliability | Network-dependent (good network = reliable) | Rock-solid (dedicated circuit, no network dependency) |
| Industry Adoption | Growing rapidly (NewTek/Vizrt ecosystem) | Broadcast standard for 30+ years |
NDI Variants Explained
Not all NDI is the same. “NDI” on a camera spec sheet could mean Full NDI (excellent) or NDI|HX (good but higher latency). Here is what each variant means for your production:
Full NDI
The highest quality NDI format. Requires a dedicated gigabit network. Used for production-quality transport between computers and switchers.
NDI|HX (High Efficiency)
The compressed format used by most PTZ cameras (PTZOptics, BirdDog). Lower bandwidth requirement but higher latency. Adequate for most live production but not ideal for real-time confidence monitoring.
NDI|HX2
Updated compression with lower latency than original HX. Supported by newer cameras (BirdDog P4K, PTZOptics Move 4K). The preferred HX format for new installations.
NDI|HX3
The latest HX format. Approaching Full NDI latency while keeping low bandwidth requirements. Supported by the newest cameras and converters. The future of NDI in production.
Use-Case Recommendations
Small church (under 200 seats, cameras within 50ft of production)
HDMIFor short cable runs, HDMI through an ATEM Mini Pro is the simplest and most cost-effective option. NDI and SDI are overkill when your cameras are close to the switcher.
Related guide →Mid-size church (200-800 seats, some cameras far from production)
SDI or NDI|HXSDI if you want zero-latency reliability and are willing to run coaxial cables. NDI|HX if you have a dedicated network and want the flexibility of software-based routing. Many churches in this range use SDI cameras to the switcher and NDI for distributing the program output.
Related guide →Large church (800+ seats, cameras 100+ feet from production)
SDISDI is the standard for large venues. Coaxial cables run reliably up to 300 feet (12G-SDI) or 1,000+ feet (3G-SDI) without active components. No network configuration required. Zero latency. The broadcast industry chose SDI for large-venue production for a reason.
Related guide →Studio or podcast production
NDIStudio environments have short distances, controlled networks, and benefit from software-based routing. NDI lets you send video between computers, switchers, and recording stations without running cables. Tools like NDI Studio Monitor and OBS NDI plugin make routing flexible.
Related guide →Multi-room or overflow distribution
NDISending program output to overflow rooms, lobby displays, and recording stations over your existing network is NDI's strongest use case. One NDI stream can be received by unlimited destinations simultaneously — no splitters, no additional cables.
Related guide →Mobile or temporary event production
SDI or HDMIEvents where you set up and tear down need physical reliability. SDI cables with BNC connectors lock in place — they cannot be accidentally pulled out like HDMI. No network configuration needed on-site. Plug in and go.
Related guide →Hybrid Setups: Using Both Together
The most effective production setups use SDI and NDI together, leveraging each protocol’s strength. Here is the setup we use and recommend:
Recommended Hybrid Architecture
Zero latency. BNC connectors lock. Reliable for the most critical signal path.
ProPresenter receives NDI natively. No additional capture card needed on the graphics computer.
ATEM records to USB directly. If using a separate recorder, SDI output maintains quality.
One NDI stream reaches every overflow display on the network simultaneously. No splitters needed.
Same NDI stream. Any computer with NDI Studio Monitor (free) becomes a display endpoint.
The key bridging device is an NDI-to-SDI / SDI-to-NDI converter. The BirdDog Mini ($395) is the standard choice — it converts in both directions, supports Full NDI, and is powered over PoE. The Kiloview E1 ($299) is a budget alternative for NDI|HX encoding.
Network Requirements for NDI
NDI’s biggest risk is a weak or shared network. Here is what you need:
Dedicated network
NDI traffic must be on its own network or VLAN, completely separate from your congregation's WiFi and office internet. Shared networks cause dropped frames and stuttering.
Managed gigabit switch
A managed switch (Netgear GS308T at $70 or Ubiquiti USW-24 at $200) with IGMP snooping enabled. IGMP prevents multicast storms — without it, NDI traffic floods every port on the switch.
Bandwidth planning
One Full NDI 1080p60 stream = ~125 Mbps. Four cameras = 500 Mbps. A gigabit switch handles 8 Full NDI streams at 1080p60. If using NDI|HX cameras (~12-20 Mbps each), a gigabit switch handles dozens of streams.
Wired connections only
Never run NDI over WiFi. WiFi is half-duplex, unpredictable, and does not have the consistent bandwidth NDI requires. Every NDI device must be wired with Cat5e or Cat6 ethernet.
Cable quality
Use Cat6 for new installations (better shielding, higher bandwidth headroom). Cat5e works for runs under 150 feet. Avoid Cat5 (no 'e') — it does not reliably support gigabit speeds at longer distances.
Frequently Asked Questions
What is the difference between NDI and SDI?
SDI sends video over dedicated coaxial cables with BNC connectors — it is a point-to-point physical connection with zero latency and zero network dependency. NDI sends video over standard ethernet networks — it uses your existing network infrastructure and supports auto-discovery, software routing, and unlimited simultaneous receivers. SDI is the proven broadcast standard. NDI is the modern IP-based approach gaining rapid adoption.
Is NDI better than SDI for church production?
It depends on your specific setup. NDI is better if you have a strong dedicated network and want flexibility — route video to any destination through software. SDI is better if you need zero-latency reliability and your cameras are far from the production area. Many churches use both: SDI from cameras to the switcher, and NDI for distributing the program output to ProPresenter, recording stations, and overflow rooms.
Does NDI have latency?
Yes. Full NDI adds 2-4 frames of latency (66-133ms at 30fps). NDI|HX (used by most PTZ cameras) adds more — typically 100-200ms. For switching between cameras during a church service, this latency is not noticeable. For real-time audio mixing or confidence monitoring where lip-sync matters, SDI's zero latency is preferable.
Can I use NDI and SDI together?
Yes, and many professional setups do. NDI-to-SDI converters (BirdDog Mini at $395, Kiloview E1 at $299) bridge the two standards. A common hybrid setup: SDI cameras feed an ATEM switcher, the program output is converted to NDI, and NDI distributes to ProPresenter, recording stations, and overflow displays over ethernet.
What about HDMI?
HDMI is the budget option for short cable runs (under 50 feet). It carries the same video quality as SDI but uses a less robust connector that can be accidentally pulled out. HDMI cables degrade beyond 25-50 feet without active cables or converters. For most small production setups, HDMI through a video switcher like the ATEM Mini Pro is perfectly adequate. Graduate to SDI or NDI when you outgrow HDMI distance limitations.
What network do I need for NDI?
Dedicated gigabit ethernet, separate from your general WiFi and internet traffic. One Full NDI 1080p60 stream uses ~125 Mbps. A 4-camera setup needs 500+ Mbps of dedicated bandwidth. Use a managed switch with IGMP snooping enabled. Unmanaged switches can work for 1-2 streams but create multicast storms with more sources. Never run NDI on the same network your congregation uses for WiFi.
At Ruah Creative House, we design production systems using both NDI and SDI depending on the venue and workflow. Our Production Lab service includes signal architecture design, equipment specification, and installation for churches and organizations.