More on lossy compression
preaching to the choir? no, rather the opposite. speaking to deaf ears =(
re: youtube.com/watch?v=R8o7T5f3UuA
ive been photoshopping since 1994. what puzzles me is when you mention the bitrate @5:49. when i started out with a pentax DSLRs in the 00's, i think it had 12-bits dynamic range. so 10 bit sounds like a joke. also, the 4:x:y is misleading. at 4:4:4, you get 24-bits, or 8 bits per channel. its really LAB mode though, so the image is transformed to 1 lightness channel, and 2 colour channels. they figured they could cheat here though, and no one would ever notice. this goes back all they way to the 1980s actually.
at 4:2:2, you get 25% colour channel detail. so the total bitrate is 12-bits, or 4 bits per channel. going down to 4:2:0, you get 12% detail, or a total bitrate of 10 bits, or 3,3 bits per channel. so its a hoax. and its even worse, jpg/mpg converts the whole image into 8x8 pixel block equations. the higher the compression value, the more advanced equations will be used. also, for high luminance detail it automagically uses more storage. for soft parts, its less.
the problem is, at low compression quality, you get block artifacts. if your image is mostly smooth (like a sunset, but also skin), the effective resolution turns to 1/64, IF its 4:4:4. at the lower quality, the block effect is out of bounds. this wasnt rectified for a long time. newer compression algorithms do a better job, and most of the vids i see on youtube do use those nowadays. but it was a problem for a long time. and still, many big sites to this day use old jpg compression methods (and low resolutions), while video compression has gone miles beyond.
anyway, the industry has done a great job of confusing people over picture quality. nowadays they think a normal png is "8 bit", the same as a low quality overcompressed jpg, which has next to no colour detail, and heavy block artifacts, basically making it below even 10 total bits of image detail, and a lot of blurriness, so the resolution is a lot less than they claim. and going up to a "whopping" 25% colour detail, they somehow think its "high dynamic range". filming video 2024 and not even having the ability to capture 100% colour detail, is a disaster.
av Heartgold Worldstone (ris och ros)
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