Re: NEWSFLASH! Linux ported to Commodore VIC-20!!
Geert Uytterhoeven (Geert.Uytterhoeven@cs.kuleuven.ac.be)
Tue, 15 Sep 1998 11:17:26 +0200 (CEST)
On Tue, 15 Sep 1998, Oliver Xymoron wrote:
> On Mon, 14 Sep 1998, Gregory Maxwell wrote:
> > This is very unrealistic. There is FAR too much noise then this. I'd say
> > that it would be at best 1/4 this.
>
> The spec I gave - 320x200x8 at 15 frames per second - is the resolution of
> an old Fisher-Price video recorder that recorded on audio tapes. NTSC
> resolution is nominally ~640x~484x~18bpp(1) at 30 frames per second so my
> original estimate was allowing for more than a 16x degradation in quality,
> or looked at another way 16:1 ECC. VHS is bad, but not so bad that that
> wouldn't work.
>
> (1) Because the signal is analog, the horizontal resolution is poorly
> defined, but 640 is pretty close to the pixel size determined by camera
> CCDs, line filters, shadow masks, etc.. The number of lines is also rather
> strangely defined. And of course, the chrominance is lower frequency
> than the luminance, which means color depth is poorly defined, but I've
> seen this 18 bit approximation in a few places.
Even digital studio equipment uses only 16 bpp, in an interleaved way: YUYV.
8 bit Y at the pixel frequency, and 8 bit U and V at half the pixel frequency.
Y = luminance, U/V = chrominance.
Greetings,
Geert
--
Geert Uytterhoeven Geert.Uytterhoeven@cs.kuleuven.ac.be
Wavelets, Linux/{m68k~Amiga,PPC~CHRP} http://www.cs.kuleuven.ac.be/~geert/
Department of Computer Science -- Katholieke Universiteit Leuven -- Belgium
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