whizkid wrote:If you have 16 bit color, there are only five bits for red and blue (and either five or six for green). That means 32 shades of blue, and one of those is black!
I don't see a moire interference pattern, I see banding. Also called posterization. Here's a link with a severe demonstration of going from 24-bit to 8- and 6-bit color:
http://www.inkjetart.com/2450/48bit/page2.html
No, not true. Playing videos is a
hardware feature of the graphic chip and is done independently of the color depth of the desktop. Actually you don't even need a graphical desktop for that, software like mplayer can show videos in plain old text mode, for instance:
http://www.mplayerhq.hu/homepage/images/shot06.jpg
http://www.slider.be/screenshots/mplayer.png
http://www.mplayerhq.hu/homepage/images ... dix-01.jpg
It works like this: The software creates a box in a certain color and does some basic video decoding. On the first picture above, this box is exactly 44x14 characters large. Then the video chip itself draws the video into the box (also scales and smooths it, if necessary). This is called an 'overlay'.
This is also the reason why you can't simply take screen shots from a video, so that most software players have a special snapshot function built in for that purpose. Try it yourself. Play a video in Windows Media Player and press the PrintScr key to take a screenshot, then open your preferred image editing software and paste it in. You'll see that (provided you have an older system that only utilizes such simple overlays and nothing more sophisticated), the video information is missing from the screen dump. With some older video chipsets (like the 256AV) you'll even have a 'hole' in that place. Open a video in your player again, place the image editor in front of it, drag it around, and you can see the current video playing through the box where the old video still should have been on your screen dump.
Another example: My ThinkPad 570, P2-333, with the NeoMagic MediaMagic 256AV 2.5MB chipset (same as in the 600E, the 600X has the 256ZX with 4MB) only shows me a slideshow when playing DVDs in XGA 24-bit on XP Pro. That's because the rendering of the video has to be done completely in software, as, with that small amount of video memory, there's nothing left to create an overlay that's large enough (I think 320x200 is the maximum that can be created with the 256AV in 24-bit XGA, not at all sufficient for DVDs). At XGA 16-bit, however, large overlays are possible, so the video plays
much better, but is still quite jerky (because of an ineffective video driver, not due to hardware restrictions; the drivers that are available for Linux don't show such performance problems with overlays at higher resolutions). When I reduce the resolution furthermore to VGA (640x480) 8-bit (!), it plays absolutely fine. There is
absolutely no banding because the video output into the overlay is totally controlled by the video chip. The desktop displays in 256 colors, but the video is in true color, 24-bit, 16 million colors.
whizkid wrote:I supposed really good playback software would dither the colors together and mask the effect, but I only tried the MediaMatic software that came with the machine. Glah.
No, there's not a single software decoder out there which does it, because it simply isn't necessary. To 'dither' implies drawing a high-res video in software, but this is extremely CPU-intensive and not very practical. A P3 at 1Ghz or even faster processors would be far away from playing any DVD smoothly.
With mplayer under Linux, even a TP 600 with a P2-266 can play DVDs absolutely fine, provided that everything is configured properly!
