Thursday, February 08, 2007
1080i and 1080p are both television picture resolutions and both qualify as high definition television, though 1080p is often referred to as Full High Definition Television. Basically both have one thousand and eighty horizontal lines of resolution. Their are two major differences between them. 1080i is scanned onto the screen in an interlacing pattern (thus the "i" in the name) and 1080p is scanned on in a progressive pattern (thus the "p" in the name). With interlacing scanning the odd numbered lines of resolution are scanned onto the screen first from top to bottom, followed a thirtieth of a second later by the even numbered lines. The result appear to be a complete picture because it all happens so fast. With the progressive pattern, the entire picture actually is scanned onto the screen all at once. A progressive picture has each line scanned on in sequence from the top of the screen to the bottom. The other major difference is that a High Definition television screen that can handle the 1080p resolution is 1,920 pixels wide by 1,080 pixels high, screens with a maximum resolution of 1080i are 1,366 pixels wide by 768 pixels high. This works out be about twice as many pixels and as a result has twice the picture quality.
The Microsoft exec mentioned earlier argued that the 1080p resolution is irrelevant because most high definition television sets automatically display pictures progressively even if the programming only calls for an interlacing picture. What he argues is that since the televisions convert the 1080i programming to 1080p programming automatically, the fact that the Blu-ray high def DVD format can deliver programming in the 1080p format to the television is irrelevant.
When looking more closely at whether or not he's right in this situation, the truth is that it depends on exactly what criteria you're looking at. For example, if you look at the strict definition of "Full" HDTV laid out above, then it doesn't really matter if high definition television sets display 1080i programming progressively because, that's still not "Full" HDTV programming simply because those same television sets don't necessarily have the 1,920 by 1,080 pixel capability that a "Full" HDTV set has and the programming that they're displaying doesn't support that many pixels. In fact high def television sets that can do that are still fairly rare on the market these days as is the programming that meets the "Full" HD standard. Looking at it this way, the exec is simply trying to take some of the wind out of Blu-ray's sails.