I alway render my mp4 off the timeline that's the Key
Don't make a master file then render from that you are
Just stepping on it for no reason,
I have a customs preset for 1080p
30Mb/s main color profile, level 5
6 frame reference multipass in apple compressor
Just remember "Garbage in Garbage out"
All video sharing site will render what ever
You upload & to my knowledge they don't
Recompress the file once already compressed
For streaming .
Plus one more thing , make sure your Level
Are right. You need to be in the 16-235 color space
Not 0-255 full range color space