Quick answer
An SDI IPTV encoder takes the professional SDI signal from broadcast cameras, switchers or routers and outputs it as an IP stream. Choose SDI over HDMI for cable runs beyond about 15 metres, locking connectors, embedded multi-channel audio and sources without HDCP.
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What SDI is and why broadcasters use it
SDI (Serial Digital Interface) is the video connection used in television studios, outside-broadcast trucks, stadiums and houses of worship. It sends uncompressed video, embedded audio and timecode over a single coaxial cable with a locking BNC connector.
An SDI IPTV encoder takes that signal and compresses it into an IP stream — the same job as an HDMI encoder, but with an input designed for professional equipment.
SDI vs HDMI for encoding
| SDI | HDMI | |
|---|---|---|
| Cable length | ≈ 100 m (3G-SDI), longer with quality coax | ≈ 10–15 m without extenders |
| Connector | Locking BNC | Friction-fit plug |
| Copy protection | None | HDCP on many consumer sources |
| Embedded audio | Up to 16 channels | Usually 2–8 channels |
| Typical sources | Broadcast cameras, switchers, routers | Cable boxes, PCs, consumer cameras |
| Cost | Higher | Lower |
SDI versions at a glance
| Standard | Bandwidth | Carries |
|---|---|---|
| SD-SDI | 270 Mb/s | 480i / 576i |
| HD-SDI | 1.485 Gb/s | 720p, 1080i |
| 3G-SDI | 2.97 Gb/s | 1080p50/60 |
| 6G-SDI | 5.94 Gb/s | 2160p30 |
| 12G-SDI | 11.88 Gb/s | 2160p60 |
Buy an encoder whose SDI input matches your highest source: 3G-SDI for 1080p60 productions, 12G-SDI if you plan 4K channels.
Where SDI encoders are used
- Houses of worship — cameras on SDI feed a switcher; the program output goes to an encoder for overflow rooms and online viewers.
- Stadiums and arenas — long cable runs from camera positions and concourse screens fed by multicast.
- Broadcast contribution — sending a feed from a venue back to a studio over SRT on the public internet.
- IPTV headends — satellite IRDs and playout servers often have SDI outputs that feed rack encoders. See IPTV headend explained.
Features to look for
- SDI loop-out so the signal continues to a monitor or recorder.
- Audio channel mapping to choose which embedded pairs go into the stream.
- Closed captions (CEA-608/708) passed from SDI into the stream if your viewers need subtitles.
- SRT with encryption for contribution over the internet.
- Redundant power and rack mounting for 24/7 operation.
Protocols, latency and multicast settings are compared in IPTV encoder protocols.
Frequently asked questions
What is an SDI IPTV encoder?
An encoder with an SDI (Serial Digital Interface) input instead of, or as well as, HDMI. It takes the professional video signal from a camera, switcher or broadcast router and outputs it as a compressed IP stream.
Why use SDI instead of HDMI?
SDI uses locking BNC connectors and coaxial cable that can run around 100 m for 3G-SDI (often more with good cable), carries embedded audio and timecode, and has no HDCP. HDMI is cheaper but limited to roughly 10–15 m and uses a friction-fit plug.
What is the difference between 3G-SDI and 12G-SDI?
3G-SDI carries up to 1080p60 on one cable. 12G-SDI carries 4K60 on one cable. There is also HD-SDI (1.5G) for 1080i/720p, and 6G-SDI for 4K30.
Can an SDI encoder feed an internet stream?
Yes. Most SDI encoders output SRT and RTMP for internet delivery as well as UDP multicast for local networks.