I'm currently in the process of re-downloading everything on x265 because of the smaller files sizes.
Whats do you guys think? Also has anybody experience with Tdarr?
This. I actually went the opposite route to OP, replaced everything 265 to 264 to avoid playback issues. My content is played on many different devices so 265 simply won't cut it.
For me the math worked out that it was cheaper to get a nuc with quick sync than to pay for the extra storage h264 uses, it's less than half the bitrate (usually ~2Mbit for 1080 compared to 8+), I have 23TB of content and my Intel nuc power efficiently transcodes to h264 on demand if the device needs it.
For codecs it is highly dependent on the release group. For 4K it is the only valid option, but for 1080p a lot of groups make their x265 encodes too small and sacrifice quality. Take a look at the group rankings in the trash guides for sonarr and radarr for a general idea if who is the best/worst.
As for Tdarr, you should only really use it for audio and subtitle processing. For one you should not re-encode video so unless you're starting with remuxes you're further degrading video that is already degraded. And for two it's best left to the people who know what settings to tweak for each movie or episode. There is no universal setting that works well for everything so while you might be able to get acceptable quality with automation it's never going to be great. The best groups already took the time and effort to get it right so you might as well get those and save yourself the time/electricity.
HEVC 10 bit in order to reduce banding for animation, especially during dark scenes. I know H264 Hi10 exists, but it has poor hardware support, so using HEVC 10 bit is the best option (I don't own a single streaming device that supports HW accelerated Hi10, besides my PC). Also, an added benefit is reduced file size. I find that doing my own encodes is very rarely worth it, but when I do, I use FFmpeg in the CLI and not tdarr.
I mainly stick to x265 for the size. I'm not too snobby with quality and for the size its fine with me. I want to like AV1 but have issue with playback on some of my devices. Usually i just play locally off a HDD on xbox (Kodi) . This may not be an issue if/when I get a NAS. Not sure if there are issues with transcoding as I haven't really looked into it
I dont use Tdarr because of its lack of more complex rules, but I do use fileflows to re-encode old videos on my server based on some rules considering its overall filesize, current format, and which library it is in. If the flow decides the file should be encoded it is converted to h265 10bit at a high bitrate, if it somehow ends up bigger than the original it does it again with a higher reduction factor.
I usually use what's available, and has the best file size for the quality. h265 is usually the best in this regard, but I look forward to more av1 encoded content. My Jellyfin server runs on my old school computer, whicj I could buy cheaply from my school, but since it has a sub-1080p screen, it works best as a server with built in UPS for me. It also has quicksync, so I've never had to think about which codecs my clients support.