WebP lossless compression

WebP, lossless, compression, image

« PNG to WebP lossless » on (stripped) 104 RGBA

average heuristic/results (work in progress...)
tool flags multithreading time saved
cwebp -lossless -m 4 -q 50 n/a 11.668s 2480.75 KB
cwebp -lossless -m 4 -q 75 n/a 13.275s 2498.41 KB
pingo -webp-lossless -s1 -nomulti forced disabled 14.445s 2534.60 KB
pingo -webp-lossless -s1 MP 4.789s 2534.60 KB
cwebp -lossless -m 4 -q 100 n/a 24.944s 2582.41 KB
cwebp -lossless -m 5 -q 75 n/a 21.216s 2539.18 KB
pingo -webp-lossless -s2 -nomulti forced disabled 21.106s 2603.82 KB
pingo -webp-lossless -s2 MP 6.848s 2603.82 KB
pingo -webp-lossless -s6 -nomulti forced disabled 28.438s 2631.19 KB
pingo -webp-lossless -s6 MP 9.438s 2631.19 KB
cwebp -lossless -m 5 -q 100 n/a 51.277s 2650.10 KB
cwebp -lossless -mt -m 6 -q 100 MT 136.266s 2671.15 KB

« PNG to WebP lossless » on LC RGBA

original cwebp -lossless -m 4 -q 100 cwebp -lossless -m 5 -q 100
592.84 KB 465.49 KB — 1.591s 466.89 KB — 2.139s
cwebp -lossless -mt -m 6 -q 100 pingo -webp-lossless -s1 pingo -webp-lossless -s9
283.56 KB — 3.587s 286.92 KB — 0.998s 284.03 KB — 1.466s

« PNG to WebP lossless » on HC RGBA

original cwebp -lossless -mt -m 6 -q 100 pingo -webp-lossless -s9
157.00 KB 13.69 KB — 1.090s 6.95 KB — 0.22s

« PNG to WebP lossless » on 380 paletted

pingo's fast heuristic for near-optimal palette sorting
tool flags multithreading time saved
cwebp -lossless -m 4 -q 50 n/a 2.964s 661.34 KB
cwebp -lossless -m 4 -q 75 n/a 3.307s 680.02 KB
cwebp -lossless -m 4 -q 100 n/a 3.588s 680.24 KB
cwebp -lossless -m 5 -q 75 MT 10.592s 676.91 KB
pingo -webp-lossless -s1 -nomulti forced disabled 5.600s 691.25 KB
pingo -webp-lossless -s1 MP 2.059s 691.25 KB
cwebp -lossless -m 5 -q 100 MT 13.509s 704.05 KB
cwebp -lossless -mt -m 6 -q 100 MT 151.179s 709.04 KB
pingo -webp-lossless -s3 -nomulti forced disabled 6.926s 712.68 KB
pingo -webp-lossless -s3 MP 2.589s 712.68 KB
pingo -webp-lossless -s5 -nomulti forced disabled 10.592s 721.61 KB
pingo -webp-lossless -s5 MP 3.868s 721.61 KB

« PNG to WebP lossless » on paletted

original cwebp -lossless -m 4 -q 100 pingo -webp-lossless -s2
421.87 KB 52.63 KB — 0.265s 39.08 KB — 0.264s
cwebp -lossless -mt -m 5 -q 100 cwebp -lossless -mt -m 6 -q 100 pingo -webp-lossless -s5
39.34 KB — 0.390s 39.34 KB — 1.653s 37.60 KB — 0.374s

« PNG to WebP lossless » on paletted

original cwebp -lossless -mt -m 6 -q 100 pingo -webp-lossless -s9
119.71 KB 104.93 KB — 3.640s 99.70 KB — 0.43s

notes

cwebp cf2f88b
cwebp -lossless -mt -m X -q Y target
pingo rc3 (03)
pingo -webp-lossless -sN target

note that this function could be work in progress and would not always perform as well as demonstrated on any samples. the lossless compression level over this transformation can be increased to get smaller filesize by using -sN:

N: from 0 to 9 — 0: fast and good compression — 9: slow, but better compression
pingo flags -sN target

machine test: CPU FX-4100 3.6Ghz — 8GB RAM — Windows 7, 64-bit