Charlie wrote:
"Michael J. Mahon" <mjma...@aol.com> wrote in message
5vSdnYkGg6mtYqPbnZ2dnUVZ_q2pnZ2d@comcast.com">news:5vSdnYkGg6mtYqPbnZ2dnUVZ_q2pnZ2d@comcast.com...
mdj wrote:
On May 7, 8:38 am, "Michael J. Mahon" <mjma...@aol.com> wrote:
I was thinking that the white RCA connector could also be a sync
output... But, IIRC, the SCART connector does have power, right?
Unfortunately, no. It provides stereo sound in/out, composite video
in/
out, and RGB in/out. The later revisions of the standard allow the RGB
signal pins to carry either YUV or S-Video. IIRC, YUV isn't even a
part of the standard.
There's also pins for the D2B automation bus and a signalling pin for
16:9/4:3 source identification.
So that white connector could also be composite sync input. Perhaps
the power connection is obscured somehow.
OK, my apologies...I thought all those RCA jacks were *outputs*!
After all, it does say RGB *to* component, and SCART is RGB, right?
And it also says:
* BRAND NEW; Scart (male) to Component (female) Adapter.
* For 'RGB' scart video signal to high quality 'Y/U/V' component video
signal.
* Signal output from DVD players, Freeview, Sky or Sky+ set-top boxes
to Component Video.
That sure *sounds* like it accepts an RGB signal on the SCART side
and outputs a Component signal on the RCA side.
I thought that SCART was also an *output* connector for AV equipment,
and that it would supply RGB that this box would convert to component.
(And with all those pins, not supplying a little power seems like an
oversight...)
Does anyone know what this $5 thing actually does?
(I'm pretty sure that the $60 box does what I described.)
In any event, this would be a straightforward way to drive a modern
TV from a IIgs RGB signal, perhaps.
Michael,
Okay, I'm a little confused. What is the difference between RGB
component
video and Y/U/V component video?
RGB is one thing, Component is another--and Y/U/V is another way of
saying "component".
"Component" is not commonly used to refer to RGB.
RGB is three, high-bandwidth analog video signals, one per primary color
of the display device.
Component refers to three analog signals: the high-bandwidth luminance
signal (Y), and the (usually lower bandwidth) color difference signals
called B-Y (or Pb or U) and R-Y (or Pr or V). (These different names
actually refer to different matrix factors used in forming the signals
and their levels, so they are not *really* identical, though their
usage is quite similar.)
RGB is a standard native to tri-color displays and computer graphics
systems, while component video is native to video recording and
transmission systems. Component video, with its typically reduced
bandwidth chroma channels, is better suited to video transmission.
And more important to me, would either one
of the boxes (assuming they do what they advertise) give me a better
screen
image than just running the IIgs output into my Monitor/TV with Roger
Johnstone's IIgs to SCART cable?
No, direct analog RGB output to an RGB input is the best you can do.
As it stands now I get a usable but not
perfect picture. The only problem seems to be in the transition from
one
color to another horizontally. For instance, if you have a line of
horizontal black pixels which turn to white there will be one pixel at
the
transition that is gray. This creates a horizontal ghosting effect
that can
be reduced by judicious adjusting of the contrast and sharpness, but
some
color combinations are worse than others. I had the impression from
past
threads that this ghosting effect was caused by the monitor not being
able
to sync with the IIgs signal frequency.
I presume you are using a digital monitor, and you are correct, the
"intermediate" value pixel is the result of the sampling clock of the
monitor not being locked to the dot clock of the IIgs. If the pattern
of gray pixels is constant and consistent over the width of the display,
then your monitor may have locked to a multiple of the dot clock.
My monitor/TV (Samsung SyncMaster 940mw) will accept several types of
video
input including both SCART and component video but to further confuse
me the
component video input is listed as Pr, Pb, Y.
Those are the common names for the "components" of "component video".
The reason for my interest in good, inexpensive RGB to component
converters is that in the US, HD monitors typically do not have RGB
inputs, but they often do have component inputs. Since component
signals can be created from RGB signals by analog matrixing (combination
with specific weighting factors), such converters are, in principle,
very simple. Unfortunately, they also seem to be relatively low volume,
so their simplicity often is not reflected in their price.
-michael
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Home page: http://members.aol.com/MJMahon/
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