Somebody save my CPU. made with Krita™

  • Armand1@lemmy.world
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    2 days ago

    I tried AV1, but it seems to work really poorly for compressing film grain which is my main usecase (movies).

    I realise you can add fake film grain, but that’s not really my thing.

    I’m sure it’s great for video game footage or low grain modern video, but that’s not what I need it for.

    For now, I’ll likely stick with x265.

    • BehindTheBarrier@programming.dev
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      21 hours ago

      I’m no expert on the grain side, but Netflix had a nice writeup about its power.

      https://netflixtechblog.com/av1-scale-film-grain-synthesis-the-awakening-ee09cfdff40b

      I also heard that when you use film grain, you should disable the denoising done on the output to properly preserve detail in the encoding. Which depends on the encoder, but should generally be possible on the ones that do film grain.

      But it might not be as good for artistic film grain that doesn’t fit normal “grain” in videos.

    • Pyro@lemmy.world
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      2 days ago

      I could be wrong, but isn’t the idea that it removes the film grain to aid compressing the ““actual”” image behind the grain, and then the player adds the grain back in during playback?

      The way you say it makes it sound like you want to compress the grain itself, and that sounds to me like a “I like the vinyl crackle in my digital media” take. Not that that’s a bad thing, everyone has preferences, but it’s also unlikely that AV1 (or any codec for that matter) was designed with the preservation of accurate film grain in mind.

      • Armand1@lemmy.world
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        1 day ago

        That’s more or less what I’m saying yes, I do like the original film grain look of movies, and often attempts to remove it removed detail, making things look smudgy.

        As for if no codec is designed for this, Blu-Rays preserve film grain, often very well, and they use x265. Granted they do this partially by brute force by having a bit rate of 30mbps+, but I’ve found that you can quite easily reduce that but rate to 12mbps and still preserve most film grain reasonably well. Especially if you use h265, the CPU version (NVENC is nowhere near as good with grain).

        By comparison, with my brief stint with AV1 I found even maxing out the settings did not seem to preserve film grain. I guess the codec is inherently heavy handed, which is fine for what it’s intended for.

        On film grain movies x264 can work, but then you typically need 20-50% more space for the same quality.

        • brucethemoose@lemmy.world
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          1 day ago

          Yeah, it does feel like AV1 is tuned for higher compression. Hence its explicitly designed to try and denoise the grain away then replicate it.

          To be clear, I’m with Pyro here (I just denoise grain away with a BM3D-V prefilter), but TBH I’d rather keep the raw rips at such high bitrates anyway.