WebP compression artifact test

I'll be compressing this one 768×768 image (of a closeup of a Romanesco broccoli, taken by me) at a bunch of WebP quality levels, and for comparison the same JPEG quality levels. All the JPEG images here use 4:2:0 chroma subsampling.

Original image

Romanesco broccoli closeup, PNG, lossless.
PNG, lossless compression, 548496 bytes. (WebP lossless image is 417206 bytes; you can see it here if you want.)

WebP, quality 90

Romanesco broccoli closeup, WebP, quality 90.
WebP, quality 90, 48418 bytes.
A bunch of lit-up pixels, mostly red and cyan, on a black background.
Difference between original image and quality-level-90-compressed WebP image.

JPEG at quality level 90

Romanesco broccoli closeup, JPEG, quality level 90.
JPEG at quality level 90, 70628 bytes.
A bunch of lit-up pixels, mostly red and cyan, on a black background, but in a different pattern from the WebP diff.
Difference between original image and quality-level-90-compressed JPEG image.

WebP, quality 80

Romanesco broccoli closeup, WebP, quality 80.
WebP, quality 80, 30952 bytes.
A bunch of lit-up pixels, mostly red and cyan, on a black background.
Difference between original image and quality-level-80-compressed WebP image.

JPEG at quality level 80

Romanesco broccoli closeup, JPEG, quality level 80.
JPEG at quality level 80, 46179 bytes.
A bunch of lit-up pixels, mostly red and cyan, on a black background, but in a different pattern from the WebP diff.
Difference between original image and quality-level-80-compressed JPEG image.

WebP, quality 50

Romanesco broccoli closeup, WebP, quality 50.
WebP, quality 50, 22016 bytes.
Many more lit-up pixels on a black background, including much more green, not too boxy though.
Difference between original image and quality-level-50-compressed WebP image.

JPEG at quality level 50

Romanesco broccoli closeup, JPEG, quality level 50.
JPEG at quality level 50, 25861 bytes.
Much like the difference between WebP-50 and original, but macroblocks are much more visible now.
Difference between original image and quality-level-50-compressed JPEG image.

WebP, quality 30

Romanesco broccoli closeup, WebP, quality 30.
WebP, quality 30, 18736 bytes.
Saturated but dim pixels, showing a lot of the shapes of the broccoli, and a lot of horizontal line artifacts.
Difference between original image and quality-level-30-compressed WebP image.

JPEG at quality level 30

Romanesco broccoli closeup, JPEG, quality level 30.
JPEG at quality level 30, 18247 bytes.
Saturated but dim pixels, showing a lot of boxing, a lot of red and green, quite a bit of blue and purple, but not showing much of the detail.
Difference between original image and quality-level-30-compressed JPEG image.

WebP, quality 10

Romanesco broccoli closeup, WebP, quality 10.
JPEG at quality level 10, 15652 bytes.
The shapes of the original image are recognizable in this image diff.
Difference between original image and quality-level-10-compressed WebP image.

JPEG at quality level 10

Romanesco broccoli closeup, JPEG, quality level 10.
JPEG at quality level 10, 8334 bytes.
A mess of green red, split along macroblock boundaries.
Difference between original image and quality-level-10-compressed JPEG image.

WebP, quality 0

Romanesco broccoli closeup, WebP, quality 0, a blurry mess but recognizable.
WebP, quality 30, 12560 bytes.
Interesting patterns of red and green: circles, horizontal and vertical lines. A few splotches of cyan where the original image has almost-white highlights.
Difference between original image and quality-level-0-compressed WebP image.

JPEG at quality level 0

Romanesco broccoli closeup, JPEG, quality level 0, basically a 48-by-48-pixel, 16-color image but with very big pixels, unrecognizable.
JPEG at quality level 30, 4719 bytes.
The original image on hallucinogens, with the brightness data almost recognizable but with the hues severely shifted along macroblock boundaries, logs of pure green, lots of pure red, an odd area with pure blue.
Difference between original image and quality-level-0-compressed JPEG image.

oatcookies.neocities.org | 2021-02-25