https://arxiv.org/pdf/1703.04421.pdf
Guetzli: Perceptually Guided JPEG Encoder
J. Alakuijala, R. Obryk∗
, O. Stoliarchuk, Z. Szabadka, L. Vandevenne,
and J. Wassenberg
Google Research Europe
March 14, 2017
Guetzli is a new JPEG encoder that aims to produce visually
indistinguishable images at a lower bit-rate than other common JPEG
encoders. It optimizes both the JPEG global quantization tables and
the DCT coefficient values in each JPEG block using a closed-loop
optimizer. Guetzli uses Butteraugli [1], our perceptual distance metric,
as the source of feedback in its optimization process. We reach a 29-45%
reduction in data size for a given perceptual distance, according to
Butteraugli, in comparison to other compressors we tried. Guetzli’s
computation is currently extremely slow, which limits its applicability
to compressing static content and serving as a proof- of-concept that
we can achieve significant reductions in size by combining advanced
psychovisual models with lossy compression techniques
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