HEVC Video Playback Green Line

Discussion in 'Videocards - AMD Radeon Drivers Section' started by zach_morris, Dec 14, 2020.

  1. zach_morris

    zach_morris New Member

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    I just got a 6800, and love it so far, but I've noticed what appear to be two glaring driver issues. I'm using this in my HTPC, so I use it for Kodi video and gaming.

    When I play an HEVC video (using say Kodi or VLC), there's a few pixel green line all the way across the bottom of the video. Turning off hardware accelerated decoding makes it go away.

    In Kodi, the fonts are strangely messed up, where the last letter of every word in the GUI appears corrupted (see picture)
    [​IMG]

    Gaming wise, so far this thing is a champ. Video playing / HTPC wise, it looks like theres still some bugs.
     
  2. IceVip

    IceVip Master Guru

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    Given how new the 6800 is, i'd say go into kodi's website and download nightly builds,
    maybe some of their developers have their hands on the new cards and fixed the issues.
     
  3. Alessio1989

    Alessio1989 Ancient Guru

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    AMD hardware decoding as always been bugged from ATI era (with bugs I meant driver crashes, OS hangs and kernel powers depending on the context). That's a small issue that will probably solved in a driver update. I can only suggest you to report the bug.
     
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  4. TheDukeSD

    TheDukeSD Member Guru

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    +1 to this part.

    The decoding part should be coded from 0. I believe there is just no other way to fix it.
    If the stuff that I read is right, part of the windows driver is coded by a team that has no access to specs regarding decoding/encoding. If this part is real than ofc there are problems because there is no proper way for each of the teams involved in writing the driver to actually test the driver overall properly (sure each part can happy work properly separated, but when combined (and a video player will combine them) you can easily end up with random behaviour that will be a nightmare to debug because you can sent it to team A and team A can just answer that it's not their code, send it to team B and team B just answers that it's not their code and both are right and wrong in same time cause it's the way the code from team A and team B interact that is causing the random behaviour... having multiple teams working at a driver makes things happen faster but... if there is a weird code interaction debuging and fixing the issues will be a nightmare especialy when the fix from team A is not enough, team B has to fix something also, and the problem is still not fixed and team A has to fix something else and so on going with a ping pong between team A and team B finally ending up in team A and team B accusing each other cause they just got bored of the nevereding problems...).
     

  5. Jackalito

    Jackalito Master Guru

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    That's not nice. Have you reported this directly to AMD?
     
  6. Astyanax

    Astyanax Ancient Guru

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    report it to @SpajdrEX and you'll have better luck getting it seen by someone who can actually effect change.
     
  7. zach_morris

    zach_morris New Member

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    I did send in a report for both issues. Here's hoping they don't get lost in the mix!
     
  8. SpajdrEX

    SpajdrEX AMD Vanguard

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    Reported, let's see if anyone from the driver guys can repro, I will try it later, I'm at work currently.
     
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  9. SpajdrEX

    SpajdrEX AMD Vanguard

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    @zach_morris Can you share a link to specific video that shows this issue you mentioned?
     
    Last edited: Dec 15, 2020
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  10. zach_morris

    zach_morris New Member

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  11. BoobZ

    BoobZ Active Member

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    Go To - System - Repdroductor- Video, Change DXVA2 to pixel shaders.
     
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  12. zach_morris

    zach_morris New Member

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    Awesome. That fixes the green line.

    After reading about it some more, it looks like this setting bypasses the GPU built in rendering settings:
    Pixel shaders means rendering through Kodi's own video shaders and video processing pipeline. DXVA means rendering is handled via the GPU drivers' built-in video shaders and video rendering pipeline.​

    The font corruption is still weird. Nothing really in setting to change for that. It only appears to effect Kodi too, but others have reported the same issue with 'old drivers':
    https://forum.kodi.tv/showthread.php?tid=335005

    Kodi uses the Freetype2 open source library to access trutype fonts. For the most part I think Kodi sends a unicode codepoint to freetype and freetype returns the character. I don't know how special unicode codepoints like non-spacing characters, variation selectors, etc are handled. But this issue seems to be with strictly ascii codepoints so that shouldn't be involved.

    Kodi renders the characters into a texture of character lines after applying size / aspect /color/ oblique (italic) / linespacing. It also has to deal with scrolling. The texture then has to be rendered into DX (for windows) vertices to be presented. I assume that something in this step is where the problem lies.
    So I'd wager there is a driver bug in there causing these issues.
     
    Last edited: Dec 15, 2020
  13. The Creator

    The Creator Member Guru

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    No problem with DXVA hardware acceleration playback of HEVC(H.265) and AVC(H.264) when I use PotPlayer.
     
  14. BoobZ

    BoobZ Active Member

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    Its Kodi only related issue.
     
  15. zach_morris

    zach_morris New Member

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    I don't think so. You can try VLC as well with DXVA enabled, and play the example file linked above:

    [​IMG]
     

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