Broadcast Colors confusion
by Arthur Psa on Dec 9, 2015 at 10:31:36 pm Last Edited By Arthur Psa on Dec 9, 2015 at 10:36:45 pm
I'm working on a DVD project, and am trying to render a sequence to be broadcast safe.
There's a particular frame with a large range of RGB values (0,0,0 to 255,255,255), so I'm using this as my test case.
First, I applied the Broadcast Colors effect (NTSC, Reduce Luminance, max amplitude 100).
This didn't seem to crush the blacks, so I also added the Levels effect, with all default values except for RGB Black Output set to 16.
When in the Composite view, I see a visible difference from the Levels effect. I don't see a visible difference when I toggle Broadcast Colors on and off, but I can see that the output changes on the YC waveform. (One of the two outputs -- I think it's chroma? -- gets compressed down to 100. The other already had a maximum of 100.)
Anyway, with both effects added, the YC waveform seems to be within limits (7.5 to 100).
I rendered the sequence to MPEG2. Out of curiosity, I brought the resulting .m2v file into After Effects.
When I hover the cursor over different parts of the test frame, I see that black areas are now as I expected: at RGB 16,16,16.
However, the white areas are at 254,254,254.
Is my file not broadcast safe then?
Or is After Effects just expanding the range back out to 255? (But then, why wouldn't blacks be expanded back down to 0?)