QNAP hardware transcoding

I've picked up a TS-251D with a Gemini Lake Intel CPU on the basis that it supports H.265 decode in hardware.
Now, it looks like the CPU has enough grunt (just) to decode in software on the fly, but I'm running 98% CPU at that point. From what I've seen, if the hardware decode is in use I should expect that to be around 60%.
I've had a look around the forums, and I've seen many references to "If you look around the forums you'll find the flags you need for ffmpeg", but I haven't actually found the post that those posts refer to. Even if I did, I suspect it may be out of date. Can anyone help me out with this?

[atc98092]

I've found that transcoding pushes the CPU usage to virtually 100% on any hardware. Both of my servers do it, but they still have plenty remaining to still do other things. I use my primary media server as a normal workstation while someone is streaming from it all the time. If someone is using the Shield, then there's no transcoding. But Roku players need audio transcoding for lots of codecs, and they can't handle VC-1 video either, so that requires full transcoding.

All I'm trying to say is not to worry too much about the CPU usage. Unless you see actual impact to the NAS functionality, it should be fine.

I've found that Kodi will do it and reduce CPU usage tremendously. It probably pegs the GPU, but the CPU was down to 10%. But that only works when using the HDMI port out of the NAS. As you say, the NAS isn't really doing anything else so I probably shouldn't sweat it. It's very unlikely that anyone is watching two H.265 streams at once, and most other formats won't need transcoding.

I'm a bit disappointed that the streaming services aren't really there yet in the QNAP ecosystem. I was hoping to make HD Station a one-stop shop instead of just a local media player. But that's nothing to do with Serviio.