UNPREMULTIPLY_ALPHA  403 libavfilter/vf_overlay.c                 alpha = UNPREMULTIPLY_ALPHA(alpha, alpha_d);
UNPREMULTIPLY_ALPHA  531 libavfilter/vf_overlay.c                 alpha = UNPREMULTIPLY_ALPHA(alpha, alpha_d);
UNPREMULTIPLY_ALPHA  581 libavfilter/vf_overlay.c                 alpha = UNPREMULTIPLY_ALPHA(alpha, alpha_d);