spudec: use csputils for color conversion

Just to get rid of that conversion copy&pasted from the internet.

R and G are swapped for unknown reasons. Testing various subtitles
seem to yield the same results as VLC. The sub-bitmap renderers output
the correct colors. The colorspace conversion is used without problems
for vo_gl, vo_gl3 and vo_vdpau. The problem is most likely that
apparently, the DVD palette read from the subtitle track extradata is
converted to YUV using vobsub_palette_to_yuv(), and swapped in the
process. Or in other words, the YUV colors spu->global_palette are
encoded with R and G swapped.

Add some utility definition to csputils.c/h to make converting single
color values easier.

1 files changed, 14 insertions, 0 deletions

diff --git a/libvo/csputils.c b/libvo/csputils.c
index b894a2f869..b0255a00dc 100644
--- a/libvo/csputils.c
+++ b/libvo/csputils.c
@@ -361,3 +361,17 @@ void mp_invert_yuv2rgb(float out[3][4], float in[3][4])
     out[1][3] = -(out[1][0] * m03 + out[1][1] * m13 + out[1][2] * m23);
     out[2][3] = -(out[2][0] * m03 + out[2][1] * m13 + out[2][2] * m23);
 }
+
+// Multiply the color in c with the given matrix.
+// c is {R, G, B} or {Y, U, V} (depending on input/output and matrix).
+void mp_map_color(float matrix[3][4], uint8_t c[3])
+{
+    uint8_t in[3] = {c[0], c[1], c[2]};
+    for (int i = 0; i < 3; i++) {
+        double val = matrix[i][3] * 255;
+        for (int x = 0; x < 3; x++)
+            val += matrix[i][x] * in[x];
+        int ival = lrint(val);
+        c[i] = FFMIN(FFMAX(ival, 0), 255);
+    }
+}