[gugagore]

I'm guessing that NTSC and PAL have a color burst on every line, vs every frame, because over an entire frame the local oscillator might not be stable enough. At least back in the day.

Same with the timing of the sweep circuits, which only need to hold sync for a single line of video.

[Shikadi]

Oh cool, didn't realize color burst was used for that, I skimmed over it in the past and misunderstood its purpose. TIL