Re: C65 on Ebay

Den Sat, 4 Nov 2017 16:29:36 +0000 skrev smf <smf@null.net>:
> On 04/11/2017 16:13, silverdr@wfmh.org.pl wrote:
> > You mean the composite one coming out of the Amigas? Can't confirm
> > either. Never used those for anything. I recall A1k2 used an
> > off-the-shelf encoder chip (by Sony if I remember correctly) but
> > can't say anything about how well it did the job in terms of
> > standard compliance.
> 
> I mean composite video at all. Composite video inputs on TV's came
> much later than NTSC and PAL (which was around the 1950's). Sure we
> all talk about composite as being NTSC or PAL, but then we talked
> about amiga's RGB output being NTSC or PAL as well.

I can assure you that composite video signals (baseband) were around in
TV studios since day one of TV broadcasts.
 
> > Probably yes, but I was more about external (to VIC chip) encoding
> > from YUV/RGB rather than putting both PAL and NTSC in. In such case
> > I hardly see a chance of having any cost advantage by putting more
> > stuff inside a chip rather than removing as much as possible..
> 
> VIC had composite encoding on chip to save money, many computers at
> the time had video chips which output rgb and then had external
> circuits to convert to composite. Having a single VIC2 for PAL/NTSC
> would mean they didn't have to keep two sets of inventory.

It was not only to save money but also to actually give a better
picture quality. We might bash the C64 and VIC-20 how much we want for
poor composite color video quality, but compared to many other
computers from the same days the picture was actually rather good.

Other companies tried their best to do something similar but failed
halfway. For example Sinclair ZX Spectrum has an ULA which does about
most of what the CPU and memory doesen't. It generates a form of
component video with the PAL phase shift/inversion on each line already
done in this IC, ready to be encoded by a separate analogue IC.

Commodore really had two advantages at the time as they owned MOS. Not
only did it make sure they had a good price and steady supply of the
IC's but they could also design custom IC's that most other companies
couldn't. (Atleast in theory Texas could also have done that, I don't
know how their TI99/4A works. Most other companies had no such
connection between an actual consumer product and semiconductor
manufaturing).

-- 
(\_/) Copy the bunny to your mails to help
(O.o) him achieve world domination.
(> <) Come join the dark side.
/_|_\ We have cookies.

       Message was sent through the cbm-hackers mailing list