Certainly, a higher speed of data transmission may prove useful for computer applications, but has little benefit for Blu-ray or HD DVD. All previous versions of HDMI have more than sufficient bandwidth to carry 1080p High Definition video along with uncompressed multi-channel PCM audio without issue. For home theater purposes, there's no gain here.
 
Deep Color: HDMI 1.3 supports 10-bit, 12-bit and 16-bit (RGB or YCbCr) color depths, up from the 8-bit depths in previous versions of the HDMI specification, for stunning rendering of over one billion colors in unprecedented detail.
Broader color space: HDMI 1.3 adds support for "x.v.Color™" (which is the consumer name describing the IEC 61966-2-4 xvYCC color standard), which removes current color space limitations and enables the display of any color viewable by the human eye.
 
Now here's something that sure sounds impressive. Who wouldn't want a greater color range in their HD video, especially when it's marketed with a sexy name like "Deep Color" that boasts of delivering billions of new color shades "beyond the capability of the human eye to perceive them"? Wow, that must be great! Of course, it begs the question of what use many of those colors are if it's impossible for human beings to ever see them, but hey let's not get bogged down in semantics.
 
Yes, as terrific of a High Definition picture as we're getting now, the occasional color banding artifact will still intrude into a Blu-ray or HD DVD picture. This is something that Deep Color or the less flashily-named xvYCC standards might improve by smoothing the gradients between color shades with a greater range of intermediary colors. That's a worthy upgrade, but here's the problem: Neither HD DVD nor Blu-ray support xvYCC or Deep Color, and never will. Those features are beyond the spec of either format.
 
Really muddying the waters on this issue is the fact that both the HD DVD and Blu-ray camps have been advertising Deep Color in their higher-end hardware, such as the recent press release from Toshiba declaring that the upcoming "top-of-the-line HD-A35 also adds support for Deep Color via HDMI, allowing compatible display devices to deliver outstanding video quality - displaying millions of possible colors to billions of possible colors."
 
"Doesn't that announcement flat-out state that the HD-A35 player will offer Deep Color? It sure seems to, but the wording is misleading. While the player itself may "support" Deep Color, in order for Deep Color to work it must be enabled in the player (possible), enabled in the television (possible), and the disc must be authored to include all of those billions of extra colors. That last one's the problem. The video encoded on HD DVD discs (and Blu-rays too) is limited to 8-bit color. So are the studio archive masters, for that matter. If some studio were to start authoring new discs with 16-bit Deep Color, those discs would be completely incompatible with the majority of existing players, rendering them unplayable. Such a disc would have to be labeled and marketed as an all-new Deep Color HD DVD or Deep Color Blu-ray format, and distinguished from the regular HD DVD or Blu-ray formats, discs for which would have to be released separately. Imagine the marketing nightmare! And for what gain? At its best, you'd get a barely-perceptible improvement in color fidelity. Yes, from a videophile perspective, even small improvements are welcome. I'd personally love to see it implemented. Ideally, both formats should have been designed with Deep Color from the start, but that isn't the way it worked out, and it's too late to change either format to incorporate it now. To do so would make no business sense whatsoever. Sorry, that's just not going to happen.
 
Long story short, even if you have a brand new HDTV that can actually render all of those billions of new colors (most can't), and even if you have HDMI 1.3 connections on both ends and every piece of equipment in-between, you'll simply never get those colors from a Blu-ray or HD DVD source. Maybe in some other type of product (like an HD camcorder or video game) or some future movie format, but not from HD DVD or Blu-ray. If you're in the market to buy a new HDTV, it might be a good idea to future-proof it by ensuring that it supports HDMI 1.3 and Deep Color, but in the here-and-now they aren't necessary."