Carl,
Millions of Americans don't know how lucky they are that the SCART system has never caught on in the United States!
SCART (Syndicat des Constructeurs d'Appareils Radiorécepteurs et Téléviseurs -- No prizes for guessing it originated in France) didn't introduce any new interface systems as such, but was designed to provide a way of making multiple connections to existing standards by one large cable and multi-way plug.
The original SCART specification included stereo audio inputs & outputs, plus video inputs & outputs to both composite and RGB standards. The idea was that by providing both of these options the receiving end of the link could use whichever signals were provided by the sending end of the link. So when connecting a VCR to a TV, for example, if the VCR provided direct RGB component outputs the TV would use them as they provide the highest quality picture. But if the VCR did not have RGB available, the TV could then use composite video instead. A control line was included in the SCART cable so that when equipment was switched on it could automatically cause some other piece of equipment (such as the TV) to select the appropriate AV inputs.
Since that original SCART specification, there have been several extensions, some
de facto but without official sanction of the original standards committee. One extension provides for S-video connection using two of the lines which would normally form part of the RGB direct link. Another uses different voltages on the switching line to select 4:3 or widescreen formats.
The result of the original "include whatever signals you have" approach and the later extensions has resulted in one diabolical mess of a standard where you can never really be sure what you're getting, since a SCART socket on one piece of equipment might not provide the same input & output options as the SCART socket on another.
For example, you might have two SCART sockets on the back of a TV, but only one provides audio outputs. One might accept composite video or RGB but
not S-video, while the other might accept composite and S-video but
not RGB. For video outputs, one might provide composite only, or composite plus RGB. Or it might be selectable for RGB or S-video. Then you can find that the SCART audio outputs from one socket will always provide the sound from the inbuilt tuner while the audio outputs from another mirror whatever is selected for the source (tuner or another SCART/AV input).
Sometimes when you select AV1 (or whatever number) the set will automatically choose RGB if available or go to composite/S-video otherwise. Sometimes you have to select these options manually (hence the source options you'll see on some sets such as AV1, AV1-Y/C, AV1-RGB etc.).
Unfortunately, sometimes even the manuals don't actually specify in full what signals are available on each SCART socket and you end up having to swap cables around in a trial-and-error fashion until you find the signals you want.
That auto-switching function is also more trouble than it's worth half the time, since yet again, some SCART sockets support it while others don't. Then if you're not careful you can end up with a situation where you switch on one piece of equipment to do something and the activated control line changes the source selection on some other piece of equipment (e.g. messing up a recording in progress).
But to get to your specific case of DVD player to TV SCART connection, the main (or only) SCART socket on the DVD player will almost certainly provide direct RGB video outputs. The only question then is whether the TV is actually using them or relying on the inferior composite signal instead.
Do you have different source options for the SCART input you are using, such as AV2-RGB or similar? If you just have one AV2 option (or whatever your SCART socket happens to be), then the set is probably selecting the RGB inputs for best quality, assuming that the SCART socket actually has RGB inputs. The manual
might tell you that somewhere.
As you can see, the whole SCART system has become one heck of a mess......
