rebuilding video library!

I find myself in a situation that i need to nuke my Qnap NAS (rebuild for 4.2 EXT4 format) and have to reload all my content back onto it. I have been backing up and gather TV and movies for YEARS. Which mean I have tons of different formats and stuff everywhere in different folders and even a few different external drives. I was thinking, since I have to reload everything I might do a MASSIVE batch convert of all my stuff to a current format. Few reason being to have everything consistent, easy to find everything, and save some space. I have a decent size NAS (raid6 12tb usage) and only using about 8Tb with photos and faily videos, back up of movies and TV shows. But I figured it would not hurt to reduce some of the old Mpeg2 codecs to something more current.

My Question…

What container and codec do you think I should use? I was thinking to be super progressive use H.265 with either a MKV or MP4 container. Right now I use Nvidia Shield to play most if not all my Plex content on my server, so i know it can handle H.265.

What program do think I should use? Qnap has a transcode program, I can load Handbrake on the NAS or i can use a Windows machine and do it externally for a few days. Or do you think it is worth have Plex transcode everything onto the NAS?

Thoughts Opinions?

By using H.265 you are painting yourself into a corner I’m afraid.
You are then restricted to use only Plex clients which can Direct Play H.265.

All other clients won’t get anything because most likely your NAS won’t have enough cpu power to transcode even one of these H.265 files
neither will ‘burning in’ subtitles be possible
nor lowering the bitrate to a more mobile-friendly number.

@OttoKerner said:
By using H.265 you are painting yourself into a corner I’m afraid.
You are then restricted to use only Plex clients which can Direct Play H.265

I assume then H.264 is the tried and tested codec of choice. I didn’t realize when Plex trans-codes for mobile, it keeps the codec. good info.

@wquibell said:
I assume then H.264 is the tried and tested codec of choice.

This is true.

I didn’t realize when Plex trans-codes for mobile, it keeps the codec. good info.

No. Plex transcodes to H.264.
But H.265 requires such an amount of cpu power just to decode it, that a transcoding will fail.