Now you can find the same 4K video from few GBs to a hundred GBs, and I am wondering: where to stop? With music there is a similar phenomenon by which after a certain bitrate it becomes an esoteric art to detect improvements. So, what is your “very good enough” bitrate for 4K videos?

  • Kissaki@feddit.de
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    1 year ago

    That is too broad of a question for a too narrow of an answer. You can answer with broad statements and generalized estimations, but I don’t think they really answer the question.

    Encoding video balances three things (extensible by two more):

    • visual quality / equivalence
    • size (stream/file size)
    • encoding time
    • decoding performance
    • decoding feature set (compatibility)

    The codec you use also has a high impact on compression ratio opportunities and capabilities. AV1, HEVC, AVC? 10-bit?

    If we define that we do not care about encoding time, so we will use the very slow preset and use all codec features available, compression ratio and quality falloff still depends a lot on what you actually encode.

    • Is it a cartoon with flat surfaces and mostly linear and partial linear or transformative movement? That can be compressed very well through differentials and transformation (movement).
    • Is it a high-grain cartoon or movie? Fine, noisy details are hard to compress, they require more information.
    • Does it have a lot of movement? A lot of vast movements and cuts? Less to keep and differentiate data with, so less efficient.

    I suspect in higher resolutions the gaps between different visual data compression ratio differs more - because a difference is elevated through higher resolution/more data.

    That being said, I don’t have or use 4K stuff, so I can’t even check for some rough numbers and visual content to size differences.