PF_ALPHA          370 libavfilter/vf_decimate.c #define PF(suf)         PF_NOALPHA(suf), PF_ALPHA(suf)
PF_ALPHA          266 libavfilter/vf_psnr.c #define PF(suf)         PF_NOALPHA(suf), PF_ALPHA(suf)