Ok this is new to me.
Firstly all my media is converted from avi to mp4 and copied from mkv to mp4 - everything.
I am looking at plexpy graphs that show transcoded/direct play/direct streams.
I have randomly checked 20-30 files and everyone that direct streamed shows as an mp4
Everyone that was transcoding shows as MKV or mpegts. (as per the attached)
So if I can work out what my converting/copying software does to show as mp4 (in plexpy)
I will have no more transcoding -ha?
My understanding is the data PlexPY reports is, in most cases, probably wrong.
So the only effect is that you cannot believe what you see in PlexPY regarding streams, transcoding, or formats.