Re: apples vs oranges (was Re: computer video (was Re: Free IBM AT))

I'm not sure how converting a modern MPG, which was not available back in 1982, into a bunch of 80x25 or 40x25 color attributes and requiring a sound blaster card, which did not exist at the time of the introduction of the PC somehow proves that one system is better than another. Especially since it was never meant to, or actually used in this way.

Yes, it's very cool, but, um, so what? Each system has its own technical merits, and it's own market, and each had both their own successes and failures.

What I mean by 2K or 4K of bandwidth is this. The stuff you see on that display is not in hires or even lowres graphics. In fact, it is just tweaking of the color attributes, which are, as expected 80x25. 80*25=2000 bytes. aka 2K. Now that display actually had 4K of memory in that mode. 2K was used for color information, broken up into nibbles, that is 4 bits for the foreground color, and 4 bits for the background color.

Even that's a rather generous assumption. You could go into 40x25 mode, and write only to the background color, so in that case you're writing to 1000 bytes, of which you only use half a byte for the 16 color background - so effectively it would by 500 bytes, though you really do have to write to all 1000 in 40x25 or all 2000 in 80x25. This is what I mean about it being the size of two icons. You're getting excited over a movie displayed in less screen real estate than an icon on a modern display.

So, yes, the total bandwidth to display a movie in this way on an IBM PC is well within it's capability, and while impressive on the surface, it's still within the limits of an 8 bit 4.77MHz 8088.

Indeed, I do have to wonder what decade we're comparing here. MPG video did not exist in 1982, and yes, when I say 720x364x2, I am talking about the Lisa and not the Mac. Incase you've not noticed, this forum is called "Lisa List." Not "The Original Mac 128 List." That 720x364x2 took up 32K of RAM vs at most 2K on the PC. Big difference in bandwidth there. It's certainly not possible to capture that video on a PC of that era and pre-process it into the format needed to display it back. So to play back a movie on a Lisa, you'd need to push 32KBytes 30 times a second. To play back this demo, you need to push 2Kbytes 30 times a second - a lot easier to do.