Here's a better pre-filter for taking S-video from a DVD player, CECB or digital cable box and making composite video that will look good on vintage and more modern color TVs without comb filters, known as notch filter chroma-luma separator sets.
You can see the difference looking at these test patterns:
The schematic:
and simulations of the response of the luma and the chroma to the output:
The object here is to keep the high frequency luma from contaminating the chroma in notch filter TVs. To avoid the crawly colors on the ref's shirt in football games. Notch filter TVs don't display the high frequency luma anyway, so you won't miss it.