why the performance of H265 hardware decode is not good on j3455 CPU

[jsjcjsjc 0]

MY Nas is QNAP 453Bmini，CPU is  J345，I find J3455 is support for 4k X265 on intel.com， but in fact the performance of H265 on emby is very bad, only can play 1080 X265 smoothly

should i do somehing on the seting of emby ?

[Charlie117 56]

Is this machine your Emby server or Emby client?

[Luke 37247]

Hi there, can we look at an example? Please attach the information requested in how to report a problem. thanks !

[jsjcjsjc 0]

Hi there, can we look at an example? Please attach the information requested in how to report a problem. thanks !

I think I got the answer from plex forums, it looks I can only direct play 4K x265 HDR movies via HDMI

 

only can play 1080 X265 smoothly

The J3455 can easily direct play 4K x265 HDR movies. I’ve the Synology DS918+, which also has the J3455. I’ve no problem direct playing 4K material.

Transcoding 4K x265 is another matter (and best avoided).

The J3455 can transcode one 4K stream as long as h/w acceleration is enabled. It works, but I avoid it. First, Plex transcodes 4K to 1080p, so the video quality drops. Second, Plex does not tone-map HDR on most clients, so the colors wash out and the video looks very poor on screen.

If you are transcoding 4K, then make sure you have subtitles disabled. Enabling subtitles when transcoding video may cause Plex to use the CPU, not the embedded GPU, for transcoding. Transcoding a single 1080p video on the CPU is pushing it for the J3455. Transcoding 4K on the CPU is out of the question.

[Luke 37247]

Can you please provide the information that I requested?

Also the upcoming 3.6 server release will be able to transcode subtitles without using the CPU. Transcoding with subtitles is still much slower than without subtitles, but least it will still be able to use the GPU. 

 

Thanks !