avfilter/vf_overlay: improve premultiplied alpha overlay for YUV

3 years ago · bdf01a9609
parent 987d2c1083
commit bdf01a9609
1 changed files with 3 additions and 2 deletions
--- a/libavfilter/vf_overlay.c
+++ b/libavfilter/vf_overlay.c
@ -538,12 +538,13 @@ static av_always_inline void blend_plane_##depth##_##nbits##bits(AVFilterContext
                    if (i && yuv)                                                                          \
                        *d = av_clip((*d * (max - alpha) + *s * alpha) / max + *s - mid, -mid, mid) + mid; \
                    else                                                                                   \
-                        *d = FFMIN((*d * (max - alpha) + *s * alpha) / max + *s, max);                     \
+                        *d = av_clip_uintp2((*d * (max - alpha) + *s * alpha) / max + *s - (16<<(nbits-8)),\
+                                                                                                    nbits);\
                } else {                                                                                   \
                    if (i && yuv)                                                                          \
                        *d = av_clip(FAST_DIV255((*d - mid) * (max - alpha)) + *s - mid, -mid, mid) + mid; \
                    else                                                                                   \
-                        *d = FFMIN(FAST_DIV255(*d * (max - alpha)) + *s, max);                             \
+                        *d = av_clip_uint8(FAST_DIV255(*d * (255 - alpha)) + *s - 16);                     \
                }                                                                                          \
            }                                                                                              \
            s++;                                                                                           \