Welcome to Electrical Engineering.

Your video quality is likely to be limited by the fact that you are using composite video rather than anything the modulator is doing.

I played around with the various connection options when I first got a DVD player (to use with a wide-screen CRT TV). I had a baseband composite video connection, without needing to use a modulator. It was still noticeably worst than the next best quality connection - S-Video.

My best connection was RGB but this was only superior to S-Video for menus generated in the DVD player itself. The DVD format records a colour difference signal so there's no extra information for a RGB connection to carry in addition to that available via S-Video.

(I'm in the UK so my TV offered RGB for component video rather than YPbPr. The DVD player had both.)

Welcome to Electrical Engineering.

Your video quality is likely to be limited by the fact that you are using composite video rather than anything the modulator is doing. The colour difference signal needs to be restricted in bandwidth before being added to the composite signal. The TV has various options for separating the luminance (black + white) and colour difference signals out of the composite signal. The cheaper options will restrict the luminance bandwidth.

I played around with the various connection options when I first got a DVD player (to use with a wide-screen CRT TV). I had a baseband composite video connection, without needing to use a modulator. It was still noticeably worst than the next best quality connection - S-Video.

My best connection was component video but this was only superior to S-Video for menus generated in the DVD player itself. The DVD format records a colour difference signal so there's no extra information for a component video connection to carry in addition to that available via S-Video.

(I'm in the UK so my TV offered RGB for component video rather than YPbPr. The DVD player had both.)