High Bandwidth Digital Content Protection, High Bandwidth Digital Content Protection
HDCP - Need Protection?
HDCP, or High Bandwidth Digital Content Protection, is a copy-protection protocol developed by Intel for use by the entertainment industry. Using HDCP, protected property can be encrypted for use with digital audio and video components. Video signals from a copy-protected DVD, for instance, can be legally passed through an HDCP-compliant device in the digital domain because it is encrypted. It requires another HDCP-compliant device to receive the signal and decrypt it. This electronic handshake is how the protocol encrypts data for copy protection.
Now, copy-protected material can be passed between devices for use with home theater. Prior to HDCP, there were no digital connection standards for digital or high-resolution TV. DVD players simply weren't allowed to use anything more than a component output signal, which is analogue. This is the reason that, when recording from an analogue source, the second generation recording suffers natural degradation (as anyone who has ever made a copy of a VHS can attest).
Now, digital information can be replicated exactly - infinite duplicates can be spawned from source material in the digital domain. HDCP filled the need for an encryption protocol to satisfy the entertainment industry and the need for audio and videophiles to use the digital technologies between devices without having to consistently convert to analogue and back again every time a signal has to pass through a device.
The two connection standards that use the HDCP protocol are DVI and HDMI, and both have helped changed the face of digital home theater technologies. The two formats had some competition at first, as DVI was adopted early with a lot of digital TVs and source devices. But DVI was an early false start and, today, HDMI is the clear winner and truly the next step in HDCP.
DVI had problems like too many different types of the same format - it's just too confusing to the average consumer. DVI-I was widely used in the computer industry for video cards and still is today. DVI-D was more popular with home entertainment but has been largely abandoned in new equipment. Those are just two DVI standards, and more have sprung up to fill niche markets, leading to consumer confusion and frustration with compatibility issues.
No such issues exist with HDMI, which is clean single plug - a small wide connector that looks much like USB and is capable of a much higher bandwidth than DVI. In fact, HDMI isn't simply a video connection standard - it can be used for audio and video simultaneously or just one or the other. Since both HDMI and DVI are compatible with the HDCP protocol they are easily adaptable. DVI-to-HDMI adaptors (and vice versa) can be used for situations where, for instance, you might have a DVI connector on one device but only HDMI on the other. These issues are common when using today's devices with the industry changing slowly to the HDMI standard.