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 HDMI Extender to send an HDMI signal over a single inexpensive Cat5e (CAT6 is preferred) cable for up to hundreds feet.

Common HDMI Connector Types

  • Standard HDMI ( for most cameras and camcorders)
  • 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, since it’s typically sent along BNC cable 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

  • HD-SDI
  • Dual-Link HDI-SDI
  • 3G-SDI
  • 6G-SDI
  • 12G-SDI
  • Quad Link SDI