this program will compress all .mp4 files in a directory, for me it has cut the size of the clips by about half (65%), without a noticable drop in quality, I think it only works on Nvidia GPU's but you can change the encoding algorithm if you need.
Do it in individual clip folders, it may go crazy go stupid aahdahdahd if you do the main clip directory, so do it by game
It does search subdirectories
It will not recompress already compressed files if you keep the same prefix
if you need help make a issue request