Actually, it's far easier than that. LD's are a composite signal, so your best bet is to use the composite output. Now, you may or may not know (and this is also for anyone else that doesn't) that the composite signal is eventually upconverted to S-video, then component (which is the DVD format), then RGB for most display devices - so one would ask: why not use one of these better connections?

Well, very few LD players have RGB, and none had component (the combo LD/DVD players did have component - but it was used solely for the DVD signal. That being said, I know of one person who actually connected the LD output to the component-video circuitry, but this procedure is not recommended for the faint of heart.)

So, what about the S-video? Well, you mentioned the comb filter, which shows some sophistication. Now, if you use the S-video of your LD player (assuming it has such - some do not), then you are using a comb filter that is approximately the same age as your LD player, which could be up to 30 years old. Chances are that the TV and/or computer video card that you are using to display or capture your LD signal is much newer, and thus its comb filter is more advanced.

I've also heard mention (though I've forgotten the specifics) that the S-video signal from some LD players has been reprocessed or overprocessed and produces a less-than-spectacular S-video signal.

Point being, you are better off using the comb filter in your TV or computer versus that of the LD player, but you should at least capture a small segment from each output and compare them to see if you notice a difference, and if so, which output produces a better picture to your eye.