HDMI's shortcomings put under the microscope
The guys over at A/V magazine Audioholics have posted a pretty in-depth article
that examines the shortcomings of HDMI, the latest and greatest in consumer high-definition audio/video interfaces. Audioholics first starts off by explaining the shortcomings of the DVI interface, whose use of twisted pair cables prevents its usage over long distances. That's not such a big problem, considering DVI is typically used with computer monitors that sit very close to their host machine. However, HDMI retained that design element instead of going with coaxial cables, seriously limiting its use over long distances—especially as HDMI has very high data rates and no error correction.
Audioholics says that at 720p and 1080i resolutions, quality cables "up to around 50 feet [15m] will work properly with most, but not all, source/display combinations." That distance becomes shorter with 1080p, and it may shorten even more with the HDMI 1.3 standard, which more than doubles single-link bandwidth without improving cable design. By contrast, Audioholics says the coaxial HD SDI interface can route a signal "hundreds of feet without errors." The site closes with talk of a new "bonded pair" HDMI cable type that reportedly supports distances of up to 150 feet (46m) at resolutions of 720p and 1080i. Audioholics says it plans to start selling the cable in late June or early July.