Okay. Well, Standard Definition and High Definition are referring to the quality of the masters that the disks are encoded from,
and to the final quality of the video on the disks. The primary thing to consider here is pixel resolution - AIR is a show broadcast in an aspect ratio of 16:9. In standard definition, this means the picture is 720 pixels wide by 480 pixels high - this is considered standard for NTSC television and DVD. (For PAL the height is instead 576 pixels, and there's a lot of fun involving FPS etc. Let's not go there tonight ^_^). In high definition, as Blu-ray is meant to be and as you'd expect a Blu-ray version of AIR to be, the resolution is somewhat higher. The minimum resolution for high definition is 1280 pixels wide by 720 pixels high, with progressive scan - this is referred to as 720p HD video. HD also refers to 1080i and 1080p video - which are interlaced and progressive scan, respecively, and boast a resolution of 1920 pixels wide by 1080 pixels high.
Additionally, HD video allows a far higher bitrate than SD video - basically (though perhaps not perfectly accurate...) the more bitrate, the better, at least assuming we're using masters and codecs that will benefit from the increased bitrate.
I've 'pinched' a chart from Wikipedia that might help illustrate what I'm talking about with resolution at any rate:
Okay, so ignoring the blue stuff on the right (We shouldn't but for the sake of this we will) the original source for the AIR disks on Blu-ray will be the yellow bit on the chart, plus the little orange bit on the left - where it says 480p - in terms of screen resolution. A true HD master would be either the dark orange part (720p) or the red part (1080p). As you can see, the image size is
enormously increased, and in terms of HD video, the greater the resolution, the better the quality.
What they've announced they are doing with the AIR masters is taking a 480i/p image and upscaling it to (assumedly) 720p, that is encoding the master to a higher resolution than it was originally intended to be seen in. And they've said this will look great etc etc, but... it's still a 480i/p master. Basically, they're cheating and not actually providing real high definition video for this AIR set. Which is very disappointing, considering that Blu-ray is intended as a high definition format.
As to the cancellation of preorders... you know, i wouldn't be incredibly surprised. Imagine, you're a Japanese fan who has bought the LE R2s, and has snapped up a Blu-ray player (or will be snapping up a PS3) for your high-def anime fix. AIR is coming out, so naturally you'll get another copy - hey, it's AIR, and it's HD! Oh wait... it's not really. It's in fact the same, but altered slightly so it might look, oh, 10% better. Give or take. And it's another 300,000 yen, after you've already dropped 7000 yen per volume for seven volumes.
I can see my reaction right there. And I'm wondering now too - the bitrate is reported to be averaging around 40mbps, which is very nice, should eliminate those issues Pony Canyon had with compression artifacts in the original releases, which I've heard were a bit poorly mastered - insufficient bitrate, perhaps. So that's fine... but the lack of a proper HD master, meaning upscaling causing possible problems in itself?
I may need to rethink this. If I'm paying for a PS3 or Blu-ray player, I'm looking for fantastic video. Not for 'hey, somewhat better than DVD!' video.
-Andiyar