HDMI Forum

Any device whose MAC address begins with C4:5D:D8 has a network interface built by HDMI Forum. This prefix (the OUI, or Organizationally Unique Identifier) is assigned by the IEEE and is the first three octets of the address.

OUI prefix

C4:5D:D8

Organization

HDMI Forum

Address

1140 East Arques Avenue, Suite 900 Sunnyvale CA US 94085

Source

IEEE OUI registry

Have a full MAC address? Look it up— we'll also tell you if it's a randomized (private) address rather than a real manufacturer prefix.