What is a handshake?

While HDMI is a very convenient way to connect devices; the technology is not problem-free.

HDMI employs HDCP copy protection to protect the digital information transferred between devices; the connected devices must establish HDCP authentication in order to transmit the signal, which is sometimes called the HDCP handshake.

If the handshake is unsuccessful, you may see a blue or otherwise discolored image, or you may just see snow on the screen.

Handshake issues are less common than they were in the early days of HDMI, but they still occur when using HDMI splitters, Home Audio Receivers and converters that change the signal from one input to another.