2026-03-12 22:21 UTC
@gsuberland@chaos.social @moira@mastodon.murkworks.net Yeah, I've been reading up on how NTSC's colour subcarrier was chosen to fit between the peaks of the luma signal to reduce interference in the low end. They knew what they were doing, even though by today's standards it seems very limited. Properly formatted signals and calibrated equipment looked and looks pretty good! If only NTSC land had the foresight to do what PAL did and ... "Alternated" the colour "Phase" between "Lines". Wouldn't have needed a tint control then, though my limited understanding is that the 29.97Hz timing drift vs 30Hz had a similar effect of reducing interference between lines.
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@gsuberland@chaos.social 2026-03-12 22:26
@emilyyoung@tech.lgbt @moira@mastodon.murkworks.net my favourite thing about that era of video was how they managed to shoehorn it all into the old B&W signals and work around all the problems that entailed. in the frequency domain the luma bandwidth overlaps the QAM chroma bandwidth, so you get crosstalk from the luma to the chroma. Sony came up with a neat trick - they realised that the chroma signal's spectrum had peaks separated at the scan line frequency, so they made a comb filter to match that, minimising luma crosstalk.