[FFmpeg-user] Colorchart and colormap

[Michael Koch]

Hi,

I have some remarks and questions about the new "colorchart" source and 
"colormap" filter.

In "colorchart" is a small error in the yellow field. It should be 231, 
199, 31.
Source: 
https://www.xritephoto.com/documents/literature/en/ColorData-1p_EN.pdf

"colorchart" is missing in the table of contents of the documentation.

Could you please also add an option for the chinese version which has 
slightly different colors?
Source: https://www.aliexpress.com/item/32738129067.html
The RGB values are shown in the 5th picture. Code is below.

In "colormap" I'd like to know how the color from the "source" image is 
calculated. If a real image of a ColorChecker is used, then the borders 
between the fields must somehow be excluded.
Is the average color over the whole 64x64 field used? Or is only one 
pixel used, from the center of the 64x64 field? Or is it the average 
color over a smaller area, for example the central 24x24 pixels?

Michael



static const uint8_t ref_china_colors[][3] = {
     { 115,  82,  69 }, // dark skin
     { 204, 161, 141 }, // light skin
     { 101, 134, 179 }, // blue sky
     {  89, 109,  61 }, // foliage
     { 141, 137, 194 }, // blue flower
     { 132, 228, 208 }, // bluish green

     { 249, 118,  35 }, // orange
     {  80,  91, 182 }, // purple red
     { 222,  91, 125 }, // moderate red
     {  91,  63, 123 }, // purple
     { 173, 232,  91 }, // yellow green
     { 255, 164,  26 }, // orange yellow

     {  44,  56, 142 }, // blue
     {  74, 148,  81 }, // green
     { 179,  42,  50 }, // red
     { 250, 226,  21 }, // yellow
     { 191,  81, 160 }, // magenta
     {   6, 142, 172 }, // cyan

     { 252, 252, 252 }, // white
     { 230, 230, 230 }, // neutral 8
     { 200, 200, 200 }, // neutral 65
     { 143, 143, 142 }, // neutral 5
     { 100, 100, 100 }, // neutral 35
     {  50,  50,  50 }, // black
};