https://aomedia.googlesource.com/aom/+/refs/heads/m93-4577/aom_dsp/psnr.c
aom_dsp/psnr.c - aom - Git at Google
aomdsppsnrcgit
https://lists.mplayerhq.hu/pipermail/mplayer-users/2003-October/038856.html
[MPlayer-users] Re: PSNR tests: mbd=2, mv0, trell, and cbp (and...
mplayeruserspsnrtestsmbd
https://ffmpeg.org/doxygen/trunk/vf__psnr__init_8c_source.html
FFmpeg: libavfilter/x86/vf_psnr_init.c Source File
ffmpegvfpsnrinitc