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> Each 8×8 block is turned into a short DCT (Discrete Cosine Transform) feature vector; distance is measured there instead of raw pixels. Was this your idea or

by esafak 3mo ago

> Each 8×8 block is turned into a short DCT (Discrete Cosine Transform) feature vector; distance is measured there instead of raw pixels. Was this your idea or the agent's? Because it feels peculiar to essentially describe JPEG, modulo the entropy coding, without mentioning its name. It was released in 1992 -- before C+C. Which makes me wonder why Westwood didn't just use JPEG too... Fun fact, DCT's inventor: https://en.wikipedia.org/wiki/Nasir_Ahmed_(engineer) https://en.wikipedia.org/wiki/Nasir_Ahmed_(engineer)

ronsor 3mo ago
Almost every lossy image and video codec uses DCT as well, not just JPEG.
- esafak 3mo ago
  Which ones came before JPEG?
  - DiabloD3 3mo ago
    H.261 is from 1988. JPEG is from 1992.
TD-Linux 3mo ago
It's not JPEG like at all, unlike JPEG it is using the DCT only for the loss function, so it can have frequency weights, having the same approximate effect as JPEG's quantization matrices (at least, according to the slopped-out description). Whether that actually improves things for this type of content is unclear.
- deleted 3mo ago
  [deleted]