The preferred consumer digital video interfaces are High Definition Multimedia Interface (HDMI) and Digital Visual Interface (DVI). DVI is commonly used by PC equipment to drive digital video displays. DVI typically supports 24-bit RGB at video rates up to 165 MHz. A DVI driver accepts 24-bit RGB data and serializes it into three serial channels. The video clock is added as a fourth channel. As the RGB data is serialized, it is encoded using an 8b/10b encoding scheme called Transition Minimized Differential Signaling (TMDS). HDMI is backwards compatible with DVI. It supports alternate (non-RGB) color spaces and includes the ability to carry digital audio.
As with DVI, HDMI data is encoded to represent active video periods and control periods. In addition, HDMI includes a third entity called a Data Island. Data Islands are used to communicate additional data during the blanking interval. For example, data islands are used to send digital audio data in HDMI.
Data delivered using a DVI or HDMI interface may be encrypted using High-Bandwidth Digital-Content Protection (HDCP). Implementation of HDCP requires a set of unique secret device keys. During authentication, the receiver will only receive content once it demonstrates knowledge of the keys. Furthermore, to prevent eavesdropping and stealing of the data, the transmitter and receiver will generate a shared secret value that is consistently checked throughout the transmission. Once authentication is established, the transmitter encrypts the data and sends it to the receiver for decryption.
Heretofore, DVI/HDMI data has only been deliverable using hard wires due at least in part to the way the data source and the display device need to communicate with each other. However, it may be desirable for a consumer to want to place a display device (such as a flat-panel television) on a wall opposite from the video source (e.g., receiver or DVD player). In this case, the consumer would typically be required to purchase and install DVI cabling from the video source to the display. However, this may be both costly and present difficult installation issues.
A wireless radio frequency (RF) system could be used between a video source and a display device. However, there may be numerous reasons for preferring a wireless optical configuration between a digital video source and a display device. For example, the hardware required for an optical wireless signal may be less complex than a RF system. Moreover, a wireless optical solution is more secure since it will not penetrate walls as with an RF system.
Therefore, a wireless optical system which eliminates the need for cabling between a digital video source and a digital video sink may be desirable.