Posted by Jack Zhao on 4th Jul 2021

HDMI stands for High Definition Multimedia Interface. In the past, digital signals from a certain source (DVD player, VCR, etc.) had to be converted to analog to be displayed on TV, resulting in a loss of signal quality. Today we have HDMI for this. HDMI is a pure digital protocol which can feed signals digitally from a source to the TV (or other digital receiver), without loss of quality.

HDCP stands for High-bandwidth Digital Content Protection, which is a copy protection that was added to the HDMI standard later by Intel Corporation.

HDCP uses authorization and encryption algorithm to protect contents. For example: the video source asks for a secret code from the destination device (TV, Monitor) before sending content, and determine if the receiving party is authorized to decrypt and play. Non compliant devices such as an old (HDMI) TV, will simply display a message that the content cannot be displayed or will display a blank screen.

History Versions Of HDCP

Versions Years Interfaces
1.0 2000 DVI
1.3 2006 HDMI , DVI , UDI & GVIF
1.4 2009
2.0 2008 Interface Independent Adaption
2.2 2013 HDMI, this version is not backward compatible with HDCP 2.0 or HDCP 1.4
2.3 2018 HDMI

HDCP Working Process

(1) Source

The source sends the content to be displayed. Examples include  STB(Set Top Box) , DVD Players, HD DVD and Blu-ray Disk players, and computer video cards. A source has only an HDCP/HDMI transmitter.

(2) Repeater

A repeater is used between source (transmitter) and sink (receiver) for various purposes such as: splits one HDMI input into multiple HDMI outputs for displaying in different screens, or removes the audio and up-conversion of video resolution etc.

The repeater has both HDMI input and output. It gets the media information from source (transmitter) at its HDMI Input Port, and decrypt the media. After performing required tasks, it encrypt the media again and send them to display device(s) through HDMI Output Port(s).

(3) Sink

The sink renders the contents for display so that it can be viewed. Examples include TVs and digital projectors. A sink has on or more HDCP/HDMI receivers.

A Simple HDCP Example

The DVD Player is connected with Television by HDMI cable. Where DVD Player works as media source and TV works sinks to display contents.

First we connect the HDMI cable between DVD Player and TV when both device are in power off mode. Then we turn on the TV and wait for a few seconds then we turn on the DVD Player.

Now the DVD Player sends his HDCP license information to the TV and request him to share his HDCP License Information. If the TV’s HDMI Port has corresponding License information, it will send to the DVD Player for verification.

After both ends verified HDCP License information of each other, connection will be established to share media information. After successful connection, encrypted contents will be transferred from DVD Player to TV, and then be decrypted and displayed correspondingly.

Do I need HDCP compliant HDMI cables?

As what you can see, HDCP protections are mainly processed in three components: Media Source, Repeater(optional) and Sink. There's no special requirement for HDMI cables.

Can I remove HDCP and play video on non-compliant TV?

HDCP is designed for copyright protection purposes, so we do not suggest anyone to remove it. As far as we know, a HDCP Remover or HDCP Stripper device with intend to copy/pirate contents is MOST CERTAINLY ILLEGAL in most countries!