avfilter/vf_colorlevels: add preserve color option

1 files changed, 83 insertions, 0 deletions

diff --git a/libavfilter/preserve_color.h b/libavfilter/preserve_color.h
new file mode 100644
index 0000000000..ac0587ad1e
--- /dev/null
+++ b/libavfilter/preserve_color.h
@@ -0,0 +1,83 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVFILTER_PRESERVE_COLOR_H
+#define AVFILTER_PRESERVE_COLOR_H
+
+enum {
+    P_NONE,
+    P_LUM,
+    P_MAX,
+    P_AVG,
+    P_SUM,
+    P_NRM,
+    P_PWR,
+    NB_PRESERVE
+};
+
+static inline float normalize(float r, float g, float b, float max)
+{
+    r /= max;
+    g /= max;
+    b /= max;
+    return sqrtf(r * r + g * g + b * b);
+}
+
+static inline float power(float r, float g, float b, float max)
+{
+    r /= max;
+    g /= max;
+    b /= max;
+    return cbrtf(r * r * r + g * g * g + b * b * b);
+}
+
+static inline void preserve_color(int preserve_color,
+                                  float ir, float ig, float ib,
+                                  float  r, float  g, float  b,
+                                  float max,
+                                  float *icolor, float *ocolor)
+{
+    switch (preserve_color) {
+    case P_LUM:
+        *icolor = FFMAX3(ir, ig, ib) + FFMIN3(ir, ig, ib);
+        *ocolor = FFMAX3( r,  g,  b) + FFMIN3( r,  g,  b);
+        break;
+    case P_MAX:
+        *icolor = FFMAX3(ir, ig, ib);
+        *ocolor = FFMAX3( r,  g,  b);
+        break;
+    case P_AVG:
+        *icolor = (ir + ig + ib + 1.f) / 3.f;
+        *ocolor = ( r +  g +  b + 1.f) / 3.f;
+        break;
+    case P_SUM:
+        *icolor = ir + ig + ib;
+        *ocolor =  r +  g  + b;
+        break;
+    case P_NRM:
+        *icolor = normalize(ir, ig, ib, max);
+        *ocolor = normalize( r,  g,  b, max);
+        break;
+    case P_PWR:
+        *icolor = power(ir, ig, ib, max);
+        *ocolor = power( r,  g,  b, max);
+        break;
+    }
+}
+
+#endif /* AVFILTER_PRESERVE_COLOR_H */