Hardware Transcoding doesn't work, AMD iGPU, Unraid

[yannn]

It is transcoding, but only the audio.  Audio transcoding will always happen on the CPU.

Code:

Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #0:1 -> #0:1 (eac3 (native) -> aac (libfdk_aac))

Stream #0 is the video.

Did I get it correct?
It works for video, so radeontop just doesn't show correct stats?
Still CPU load is for audio transcoding? 

Isn't it too much CPU from that? 4cores - 8 threads load 35-65%
Screenshot from Unraid dashboard: https://imgur.com/a/e9Okhte