NTSC Video Wiki Old Brightness Measurement Source

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Joshua Cadmium
Posts: 6
Joined: Sun Oct 16, 2022 6:46 pm

NTSC Video Wiki Old Brightness Measurement Source

Post by Joshua Cadmium »


I was looking at the NTSC Video wiki and noticed that the old measurements of the PPU brightness said that the source was unknown.

I did a quick search and the source is actually kevtris: viewtopic.php?t=2113 .

So, the reason the levels are so much higher than 1vp-p is because it was measured close to the PPU before it was turned into composite video levels.

Here are my calculated IRE values for the data from kevtris:

Sync: -40.00 IRE
Colorburst L: -23.12 IRE
Colorburst H: 31.75 IRE
Color 0D: -13.03 IRE
Color 1D: 0.000 IRE
Color 2D: 34.14 IRE
Color 3D: 79.46 IRE
Color 00: 44.32 IRE
Color 10: 76.07 IRE
Color 20: 111.2 IRE
Color 30: 111.2 IRE

(I am treating 1D-Sync as exactly 40IRE and scaling everything else from that: [((1.300-0.781)/40)*absolute]. I also think I read on the wiki previously that 20 and 30 were at 111.214 IRE, which would be the same math.)

It's also nice to see that these figures are within about ±2 IRE of the measurements by lidnariq.
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