"red" wrote in message
...
The reason why RGBHV is the best signal you can get applies to all types
of
video signals.

snip

As you can see, by separating different signals, you can improve the
quality
of the image. snip


I don't see that at all. Of course, what you said is nearly always correct.
Sometimes, however, there are cases where using composite can be superior to
s-video in consumer applications where the a comb filter is inferior to the
display or destination comb filter. All else being equal, you are correct.
There is sometimes more to the story. For instance, some cable boxes have
really cheap comb filters to get an s-video connection, while many high end
televisions have much better filters and you get a better result by using
the composite output.

I was under the impression that the trend toward sending difference signals
and Y was because RGBHV requires much wider bandwidth due to the duplication
of the Y component. Also, the separation of the sync has no great
advantage, but does increase the probability of bad connections, having 5
lines instead of 3. Since most video is recorded, encoded, and supplied
with Y, R-Y, B-Y, transcoding to RGBHV introduces another step of processing
that would potentially degrade the signal. Finally, duplicating the Y in
all three R, G, & B leaves the possibility of corrupting the Y component.
Thus, in any application in which the source is not directly connected to
the display, there are significant advantages to using color difference
signals compared to "pure" component RGBHV and no great advantages to the
latter. Again, there is sometimes more to the story.

Leonard Caillouet