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Change guess_palette so its output matches the most common palette.

This means it uses full brightness range and brightness
increasing instead of decreasing with index of non-opaque
color.

Based on patch by Alexandre Colucci [alexandre elgato com]
This commit is contained in:
Reimar Döffinger 2011-04-30 23:00:17 +02:00
parent 148ffcd2ce
commit cf16104ad1

View File

@ -120,6 +120,14 @@ static void guess_palette(uint32_t *rgba_palette,
uint8_t *alpha,
uint32_t subtitle_color)
{
static const uint8_t level_map[4][4] = {
// this configuration (full range, lowest to highest) in tests
// seemed most common, so assume this
{0xff},
{0x00, 0xff},
{0x00, 0x80, 0xff},
{0x00, 0x55, 0xaa, 0xff},
};
uint8_t color_used[16];
int nb_opaque_colors, i, level, j, r, g, b;
@ -138,18 +146,18 @@ static void guess_palette(uint32_t *rgba_palette,
if (nb_opaque_colors == 0)
return;
j = nb_opaque_colors;
j = 0;
memset(color_used, 0, 16);
for(i = 0; i < 4; i++) {
if (alpha[i] != 0) {
if (!color_used[colormap[i]]) {
level = (0xff * j) / nb_opaque_colors;
level = level_map[nb_opaque_colors][j];
r = (((subtitle_color >> 16) & 0xff) * level) >> 8;
g = (((subtitle_color >> 8) & 0xff) * level) >> 8;
b = (((subtitle_color >> 0) & 0xff) * level) >> 8;
rgba_palette[i] = b | (g << 8) | (r << 16) | ((alpha[i] * 17) << 24);
color_used[colormap[i]] = (i + 1);
j--;
j++;
} else {
rgba_palette[i] = (rgba_palette[color_used[colormap[i]] - 1] & 0x00ffffff) |
((alpha[i] * 17) << 24);