1080p HDR problem, 10 bit video stutter

Hi guys,
Happy new year and all :slight_smile:

I’m on n5max 905x2, 9.2.1 stable, and have two issues with recent files I tried to play.

  1. 1080p HDR not playing as HDR:
    sample file: https://www78.zippyshare.com/v/heosC2td/file.html
    my TV detects this as HDR and plays it in HDR mode (using usb stick).
    but CoreELEC plays this with washed out colors (both movie itself and the OSD icons).

  2. video stutters:
    sample file: https://www78.zippyshare.com/v/CrdJEXiw/file.html
    it’s a sample from a 10bit animated file. I get stutters from 00:32 to 00:45.
    PC plays this just fine (using VLC).

another small question.
while testing the 10bit/hdr issue, I used “cat /sys/class/amhdmitx/amhdmitx0/config”, and I’ve noticed that it says “Colour depth: 10-bit” no matter which file is played, 8 bit or 10 bit.
is this a problem?


I also noticed that issue with 1080p HDR files. As a workaround you can remove 1080p modes from the whitelist so 1080p will be upscaled to 4K. Upscaled to 4K 1080p files play as HDR.

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  1. Works fine in HDR here. Make sure that the file is played with hardware decoding. If it is, then your TV may not support HDR at 1080P.
  2. That is a 10-bit H264 file, which can not be hardware decoded, meaning it uses software decoding. The S905X2 is not powerful enough for FullHD software decoding.
  3. 10-bit color depth is normal, CE will always select the highest supported color depth.

thanks for the quick reply.

  1. file is played with hardware decoding. how come the tv’s internal player IS able to play it in HDR? do you mean the problem the tv is having is with input signal which is 1080p HDR?
  2. thanks, wasn’t aware of this.
  3. don’t fully understand this. if the video is 8-bit, what is being expanded to 10-bit?

I’m not sure why the TV can play it from the internal player in HDR, but not through CE, but I’ve tried it on my LG TV and can confirm that it’s working perfectly fine for me. Although I am using a new build, maybe try the latest nightly and see if there’s any difference.

In regards to 8/10 bit thing. Nothing is being expanded. The signal to the TV is 10 bits, but the video is still 8 bits. There is no dithering going on.

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it’s very strange, but now suddenly the HDR file plays fine, I get HDR indicator on my TV, and the colors look good.
don’t really know what I did, I had a lot of testing going on yesterday involving rebooting the streamer, restarting kodi, sending various cec commands, editing cron jobs, restarting the TV/AVR (which I did plenty times before and it didn’t change the outcome).
is there any debug log I can take now, and the next time it doesn’t work, to help understand the reason?

8 bit video is often played at 10 bits or 12 bits. The 8 bits take the 8 highest bits and the 2 or 4 least significant bits that take you to 10 or 12 bits are just padded with zeroes usually.