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  1. Hello, I encoded 4k video with ffmpeg like this:
    Code:
    ffmpeg -i orig.mp4 -preset placebo -c:a copy -c:v libx264 -crf 30 final.mkv
    but when I trying play this video I see random artifacts.
    Image
    [Attachment 73653 - Click to enlarge]

    Also I noticed this problem appears only on 4k videos (FullHD is okay) AND if playing with hardware acceleration (when stream decoding by Video Decode gpu block) AND only with placebo preset (veryslow and any another preset doesn't "produce" this artifacts), but if I play with software decoding, everything plays ok without any artifacts.
    Thanks!
    Last edited by olodar; 5th Sep 2023 at 14:35.
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  2. Try reducing b-frames to 8.

    Code:
    ffmpeg -i orig.mp4 -preset placebo -c:a copy -c:v libx264 -crf 30 -x264opts bframes=8 final.mkv
    Quote Quote  
  3. Originally Posted by jagabo View Post
    Try reducing b-frames to 8.

    Code:
    ffmpeg -i orig.mp4 -preset placebo -c:a copy -c:v libx264 -crf 30 -x264opts bframes=8 final.mkv
    Thanks for your answer! Unfortunately it's not help:
    Image
    [Attachment 73664 - Click to enlarge]
    Quote Quote  
  4. Originally Posted by olodar View Post
    ...but if I play with software decoding, everything plays ok without any artifacts.
    That means your problem isn't an encoding problem, but a playing problem.
    Forget hardware acceleration for 4k videos on your PC.
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  5. Originally Posted by olodar View Post
    Originally Posted by jagabo View Post
    Try reducing b-frames to 8.

    Code:
    ffmpeg -i orig.mp4 -preset placebo -c:a copy -c:v libx264 -crf 30 -x264opts bframes=8 final.mkv
    Thanks for your answer! Unfortunately it's not help:
    I thought that would be it. There are a few more differences between veryslow and placebo you can try changing:

    Code:
    veryslow:  cabac=1 / ref=16 / deblock=1:0:0 / analyse=0x3:0x133 / me=umh  / subme=10 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=24 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=6 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=8  / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=60 / rc=crf / mbtree=1 / crf=16.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40                 / aq=1:1.00
    
    placebo:   cabac=1 / ref=16 / deblock=1:0:0 / analyse=0x3:0x133 / me=tesa / subme=11 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=24 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=0 / chroma_qp_offset=-2 / threads=6 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=16 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=60 / rc=crf / mbtree=1 / crf=16.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40                 / aq=1:1.00
    Or just use the veryslow preset. You won't see any difference anyway.
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  6. Originally Posted by ProWo View Post
    Originally Posted by olodar View Post
    ...but if I play with software decoding, everything plays ok without any artifacts.
    That means your problem isn't an encoding problem, but a playing problem.
    Forget hardware acceleration for 4k videos on your PC.
    I tried on different devices - smartphone, laptop, PC - everywhere with hardware decoding artifacts appears. Besides, there's no artifacts with any other preset, this problem only with placebo preset.
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  7. Member
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    Aug 2018
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    Can you attach the problematic fragment?
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  8. Originally Posted by rgr View Post
    Can you attach the problematic fragment?
    Sure - https://kazakhcloud.gsgt.ru/index.php/s/zs77fEqbqZM8K5T

    Also, I was a little wrong, in fact, "placebo" and "veryslow" gives artifacts too. "slower" already encodes good.
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  9. Member
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    Originally Posted by olodar View Post
    Originally Posted by rgr View Post
    Can you attach the problematic fragment?
    Sure - https://kazakhcloud.gsgt.ru/index.php/s/zs77fEqbqZM8K5T

    Also, I was a little wrong, in fact, "placebo" and "veryslow" gives artifacts too. "slower" already encodes good.
    "Internal Server Error

    The server encountered an internal error and was unable to complete your request.
    Please contact the server administrator if this error reappears multiple times, please include the technical details below in your report.
    More details can be found in the server log."
    Quote Quote  
  10. Originally Posted by olodar View Post
    I was a little wrong, in fact, "placebo" and "veryslow" gives artifacts too. "slower" already encodes good.
    In that case try setting bframes=3 and ref=8.
    Quote Quote  
  11. Originally Posted by rgr View Post
    Originally Posted by olodar View Post
    Originally Posted by rgr View Post
    Can you attach the problematic fragment?
    Sure - https://kazakhcloud.gsgt.ru/index.php/s/zs77fEqbqZM8K5T

    Also, I was a little wrong, in fact, "placebo" and "veryslow" gives artifacts too. "slower" already encodes good.
    "Internal Server Error

    The server encountered an internal error and was unable to complete your request.
    Please contact the server administrator if this error reappears multiple times, please include the technical details below in your report.
    More details can be found in the server log."
    Excuse me, reup: https://kazakhcloud.gsgt.ru/index.php/s/pFJCGdzgWp4gk98

    Originally Posted by jagabo View Post
    Originally Posted by olodar View Post
    I was a little wrong, in fact, "placebo" and "veryslow" gives artifacts too. "slower" already encodes good.
    In that case try setting bframes=3 and ref=8.
    No, some artifacts are still appears. BTW, "x264opts" is deprecated, need use "x264-params" instead - https://trac.ffmpeg.org/wiki/Encode/H.264 "Warning: Do not use the option x264opts, as it will eventually be removed. Use x264-params instead.".
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  12. Member
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    Wrocław
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    Originally Posted by olodar View Post
    Originally Posted by rgr View Post
    Originally Posted by olodar View Post
    Originally Posted by rgr View Post
    Can you attach the problematic fragment?
    Sure - https://kazakhcloud.gsgt.ru/index.php/s/zs77fEqbqZM8K5T

    Also, I was a little wrong, in fact, "placebo" and "veryslow" gives artifacts too. "slower" already encodes good.
    "Internal Server Error

    The server encountered an internal error and was unable to complete your request.
    Please contact the server administrator if this error reappears multiple times, please include the technical details below in your report.
    More details can be found in the server log."
    Excuse me, reup: https://kazakhcloud.gsgt.ru/index.php/s/pFJCGdzgWp4gk98
    Download doesn't work -- just nothing happens...
    Quote Quote  
  13. Member
    Join Date
    Mar 2008
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    United States
    Search Comp PM
    I was able download it on my phone using Firefox/uBlock origin
    Quote Quote  
  14. Originally Posted by rgr View Post
    Originally Posted by olodar View Post
    Originally Posted by rgr View Post
    Originally Posted by olodar View Post
    Originally Posted by rgr View Post
    Can you attach the problematic fragment?
    Sure - https://kazakhcloud.gsgt.ru/index.php/s/zs77fEqbqZM8K5T

    Also, I was a little wrong, in fact, "placebo" and "veryslow" gives artifacts too. "slower" already encodes good.
    "Internal Server Error

    The server encountered an internal error and was unable to complete your request.
    Please contact the server administrator if this error reappears multiple times, please include the technical details below in your report.
    More details can be found in the server log."
    Excuse me, reup: https://kazakhcloud.gsgt.ru/index.php/s/pFJCGdzgWp4gk98
    Download doesn't work -- just nothing happens...
    Try direct link then - https://kazakhcloud.gsgt.ru/index.php/s/pFJCGdzgWp4gk98/download/SGCAM_20230827_035840892.mp4
    Quote Quote  



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