Guetzli: Perceptually Guided JPEG Encoder

Understand

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, 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.