The testdata was generated via: cwebp foo.png -o foo.lossy.webp dwebp -pgm foo.lossy.webp -o tmp.pgm convert tmp.pgm foo.lossy.webp.ycbcr.png rm tmp.pgm TBR=r R=r CC=golang-codereviews https://golang.org/cl/107330043
The testdata files were created by: cwebp video-001.png -o video-001.webp dwebp -pgm video-001.webp -o tmp.pgm convert tmp.pgm video-001.webp.ycbcr.png rm tmp.pgm LGTM=r R=r CC=chaishushan, golang-codereviews https://golang.org/cl/91700044