2005 HDTV Report, Part 17: Digital Connectivity

[Rodolfo]

This part 17 deals with digital connectivity (DVI, HDMI, IEEE1394).

The DVI (Digital Visual Interface) 1.0 specification was introduced in April 1999 for creating a digital connection between a PC and a display device. It is a point-to-point connection with enough bandwidth for uncompressed HD signals, but it was not implemented for audio. On December 9, 2002, the seven founders of HDMI (High-Definition Multimedia Interface) announced the 1.0 specification of this connectivity standard, the enhanced, more robust form of DVI. The standard supports HD uncompressed video, 8-channel digital audio (reportedly up to 192 KHz), and some control signals on a single cable (15 mm, 19 pin), while using less than half the available bandwidth. HDMI has the same video capacity as DVI, or up to five Gbps of bandwidth, double what a HD signal would require, and is backward compatible with DVI by using an adapter. There is a two-way communication between the source device and the receiving device by which the receiving device tells the source about its multi-channel capabilities. Most new DTV monitors and integrated displays have incorporated DVI or HDMI inputs, however, some displays were reported to have interoperability problems.

IEEE1394 is a digital interface conceived by Apple Computer in 1986, and it was called "Fire Wire" for its fast speed of operation. In 1995, the Institute of Electrical and Electronic Engineers (IEEE) adopted the serial bus as its standard 1394. Sony trademarked their name iLink for their implementation of the 1394 bus as a 4-pin connector. In March 2000, an updated specification was approved, the 1394a. In 2001, the IEEE 1394 "b" standard emerged as a network technology (rather than "a", as serial bus); it is capable of moving data streams at faster speeds over longer distances than the original. The connection is now being used by a growing number of DTV equipment manufacturers for the transmission of compressed HD signals, such as D-VHS recording and networking DTV equipment.

Since 2003, most manufacturers released a large variety of products adopting these connections to enable their equipment for digital connectivity, IEEE1394 for compressed HD video from integrated TVs with tuners, cable and OTA HD-STBs mainly for recording purposes (using DTCP), and DVI/HDMI for uncompressed HD video for the viewing of protected content (using HDCP).

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