diff options
Diffstat (limited to 'libavfilter')
| -rw-r--r-- | libavfilter/vf_lut.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/libavfilter/vf_lut.c b/libavfilter/vf_lut.c index fff5a2ba31..0b7a2cac02 100644 --- a/libavfilter/vf_lut.c +++ b/libavfilter/vf_lut.c @@ -161,15 +161,32 @@ static double compute_gammaval(void *opaque, double gamma) return pow((val-minval)/(maxval-minval), gamma) * (maxval-minval)+minval; } +/** + * Compute Rec.709 gama correction of value val + */ +static double compute_gammaval709(void *opaque, double gamma) +{ + LutContext *s = opaque; + double val = s->var_values[VAR_CLIPVAL]; + double minval = s->var_values[VAR_MINVAL]; + double maxval = s->var_values[VAR_MAXVAL]; + double level = (val - minval) / (maxval - minval); + level = level < 0.018 ? 4.5 * level + : 1.099 * pow(level, 1.0 / gamma) - 0.099; + return level * (maxval - minval) + minval; +} + static double (* const funcs1[])(void *, double) = { (void *)clip, (void *)compute_gammaval, + (void *)compute_gammaval709, NULL }; static const char * const funcs1_names[] = { "clip", "gammaval", + "gammaval709", NULL }; |