How to fix purple-red video with Avisynth?

[VideoFanatic]

Short MPEG2 sample

I tried this but it still doesn't look right:

ConvertToRGB32(interlaced=true). RGBAdjust(1.0, 1.0, 1.0, 1.0, -20, 0.0, 0.0, 0.0, 1.00). converttoyv12

[pandy]

Give a chance to Color YUV (Autowhite?) perhaps http://strony.aster.pl/paviko/hdragc.htm can help

[VideoFanatic]

Thanks. I'll give it a try. Could you suggest a script please as I'm looking at the documentation and I'm not sure what I'm supposed to do to lower the purple.

[pandy]

https://forum.videohelp.com/threads/266294-How-can-you-automatically-correct-White-Balance-in-Video

https://forum.videohelp.com/threads/266294-How-can-you-automatically-correct-White-Bala...=1#post1591910

http://strony.aster.pl/paviko/hdragc.htm

shift_u, shift_u [int]
parameters for sublte white balance correction, shift_u < 0 - removes blue tint, shift_u > 0 - removes yellow tint, shift_v < 0 - removes red tint, shift_v > 0 - removes green tint (default 0)

This plugin support YV12 and YUY2 color space.
Usage:
AVISource(...)
SeparateFields() #if content is interlaced
HDRAGC()
Weave() #if content is interlaced

Also manually in VirtualDub filter "HSV adjust" can be used.

ColorYUV(autowhite=true)
SeparateFields() #if content is interlaced
HDRAGC(coef_sat = 1.0, shift_u=-25 ,shift_v=15, reducer =1.5)
Weave()

btw i completely forget about NTSC YIQ space - try Tweak(hue=-33) before all next steps (i mean before you try to tweak colors) and check: http://avisynth.org/mediawiki/Tweak

[jagabo]

Shifting u and v (off_u and off_v in ColorYUV) won't work for this video since different parts of the video have different shifts, and even within frames the shift varies depending on the brightness etc.

[pandy]

Shifting u and v (off_u and off_v in ColorYUV) won't work for this video since different parts of the video have different shifts, and even within frames the shift varies depending on the brightness etc.

I know that overall quality is poor but anyway still can be tweak and a bit improved:

[themaster1]

this is a work for RGB equalizer (vdub filter) imo
rgbeq:
http://www.mediafire.com/?c221zauh0k45ib5
and:
http://www.mediafire.com/?5u0cbnm1lob6x70

work with 5 sliders minimum

[sanlyn]

Histograms look "normal". For instance, you don't have an RGB histogram with red pumped at the right, in reverse of the other colors. So IMO there's something screwy with the YUV channels. U or V been switched? A channel inverted ? ? ?

[jagabo]

It's not swapped U and V, or one of them inverted. You can easily test with:

SwapUV() # swap U and V

YtoUV(UtoY().Invert(), VtoY(), last) # invert U

YtoUV(UtoY(), VtoY().Invert(), last) # invert V

[sanlyn]

Yep, I went thru those with some very nice scripts you posted in an old thread. But no conclusions. In some scenes reds are purple, in others reds are green. But the histograms always look "balanced" (no one channel looks out of whack or displaced). Someone did a real number on this one.

[pandy]

Yep, I went thru those with some very nice scripts you posted in an old thread. But no conclusions. In some scenes reds are purple, in others reds are green. But the histograms always look "balanced" (no one channel looks out of whack or displaced). Someone did a real number on this one.

What is color of the floor on ring? - perhaps those closeup parts are tinted green by strong light reflected from floor - this can give strong green tint and if this will be accumulated with bad source, bad capture and overall low quality for recordings thus in results almost non rescue video -