Video Encoders

HDMI vs. SDI Video Connections: What's the Difference?

When streaming events live, there are several ways to output video and audio from a video source to a streaming device. Two of the most common are HDMI (High Definition Multimedia Interface) and SDI (Serial Digital Interface). This post sets out to explain the differences between the two.

What is HDMI?

HDMI is a video standard commonly used in consumer/prosumer environments. HDMI sends uncompressed video and embedded audio signals to any device that can display or encode video.

Typically, HDMI signals can run up to 50 feet without needing an amplifier, a device that allows you to boost the HDMI signal to another cable so it can run longer. If you find yourself in need of additional signal length, you can also use these converters to send an HDMI signal over a single, inexpensive Cat5e (Cat6 is preferred) cable for up to 390 feet.

Common HDMI Connector Types

– Standard HDMI

– Mini HDMI (DSLR + Mini Camcorders)

– Micro HDMI (GoPros + Action Cams)


What is SDI?

SDI is a professional video signal that is preferred in production environments because of its longer range (up to 300 feet) and reliability. It’s typically sent along BNC Cabling that has specialized connectors on each end to lock into the devices they connect to.

If you’re in an environment in which your cable could be unplugged or tripped over (which should also be taped down anyway), SDI connections are ideal.

Common SDI Standards


– Dual-Link HDI-SDI

– 3G-SDI

– 6G-SDI

– 12G-SDI

– Quad Link SDI

What's the difference between various SDI Signals?

Watch this Tech Tips video for a more in-depth comparison between HDMI and SDI:

Final Thoughts + Additional Resources

Now that you understand the difference between these two connectors, you might want to check out some other streaming terminology. Having a solid grasp on industry vocabulary will help you navigate the technology available to you, troubleshoot potential issues, and improve the overall quality of your streams.

Read Your Ultimate Streaming Glossary: The Words You Need to Know.

Here are a few other resources you might find interesting:

HEVC (H.265) vs. AVC (H.264): What’s the Difference?

This Is Why Your Live Stream Lags: Intro to Streaming Latency

Hardware Video Encoder Comparison: BoxCaster vs Teradek VidiU vs Digicast DMB-8800A

Hardware Vs. Software Encoders: 6 Reasons Hardware Encoders Are Better

HEVC's Impact on Live Streaming

What's the Difference Between Various SDI Signals?