The best part is that a modern CPU may well notice that those instructions don't change anything and skip them entirely.!movq mm5, [Ecx]
!movntq [Ecx], mm5
So the guy reads the file, laboriously rewrites quadwords one by one, with the intention of bypassing the cache, then writes the whole buffer back... (obtaining a new identical file) that plays back - later - better. Sometimes, I don't get those guys. On one hand, they demonstrate a certain level of knowledge, on the other hand, I can't see what led them to the idea that what they are doing could be useful. I must be missing something really deep...