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#chroma-subsampling
1 articles
01
2026-08-05
·
Image Codecs
·
★ MEMBER
·
9 min read
Why JPEG Degrades — The DCT and Quantization from Scratch
When a photo shrinks to a tenth of its size, what exactly was thrown away? Colour conversion, 8×8 blocks, the DCT, the quantization table and the zigzag scan — followed by what the number in "quality 90" really is, and where blocking and mosquito noise are born. Ending with the decisions people who ship images actually make.