What’s the digital process of lowering the quality of a photo or video? Also is the opposite process a thing or just movie things?
In: Technology
The process itself depending on algorithm. But generally, algorithm tries to analyze an image and find it’s less significant details and then remove it. For example if you have three gray pixels in a row with middle one just barely darker, algorithm could decide that this color deviation isn’t important and make it same color as neighbouring pixels. Less details – less information – less bytes to store this image/video.
But doing opposite is… well, technically impossible (because if we don’t have an information about smallest details, we obviously can’t know about those details).
As u/Pocok5 mentioned, there’s exists algorithms that actually could restore lost information, but that just means such an algorithm should store information about which details usually getting lost, how they appear, when and where. So, basically, that means that we store such information not in image/video data, but in algorithm itself, but still we need some bytes to store it, sometimes even more than in uncompressed file. And such process is not accurate, it just gives us resulting image that looks same **quality**, but not same **image**. For example, if we had a picture of a grassy plain, which is compressed so we couldn’t see any plant details, we theoretically can improve it and see an actual plants with a leaves, which will look naturally, but that’ll be a completely different plants, not having anything in common with the original image except that it’s a same looking grassy plain.
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