Is it possible to emulate an NTSC image in GIMP?

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psycopathicteen
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Re: Is it possible to emulate an NTSC image in GIMP?

Post by psycopathicteen » Mon Jan 21, 2019 7:11 pm

I successfully emulated an adaptive NTSC comb filter in GIMP. I used 4 different filtering modes, a vertical filter, a horizontal filter, and 2 diagonal filter, and I used edge detection to determine which of the 4 filters to use. Non-edges use the average of the 4 filter types.
NTSC comb filtered Sailor Moon.png


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tokumaru
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Re: Is it possible to emulate an NTSC image in GIMP?

Post by tokumaru » Tue Jan 22, 2019 5:11 pm

This is all fake video simulations though, I'm pretty sure psycopathicteen is talking about real NTSC encoding.

psycopathicteen
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Re: Is it possible to emulate an NTSC image in GIMP?

Post by psycopathicteen » Tue Jan 22, 2019 5:34 pm

I tried to do the same thing as the Sailor Moon picture with the title screen of SMAA+SMW, and for some reason I can't get the outline and shading of Mario's hat from bleeding. Did Mario's hat always bleed on NTSC? I remember it being sharp and clear on my TV set.

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bazza
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Re: Is it possible to emulate an NTSC image in GIMP?

Post by bazza » Tue Jan 22, 2019 7:00 pm

tokumaru wrote:
This is all fake video simulations though, I'm pretty sure psycopathicteen is talking about real NTSC encoding.
I thought that only only wish effects CRT
Better real conversion :D

psycopathicteen
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Re: Is it possible to emulate an NTSC image in GIMP?

Post by psycopathicteen » Mon Jan 28, 2019 4:52 pm

Super Mario NTSC.png
For this one, I used a high-pass filtered chroma signal instead of a band-pass filtered chroma signal. This technique would work with composite, but not very well with RF because of chroma bandwidth.

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