wavif
wavif is an experimental PNG/JPG to AVIF converter which use libaom (3.5.0) — the main purpose of it was to test some ideas for small RGBA PNG, especially on PNG which have lot of nearly translucent/invisible data. -auto (or -auto=N) is an automatic optimizer which uses heuristics to select the trade-off — it sets 'quality', chroma subsampling and 'effort'. useful range atm are 10, 20, 30, etc.
chroma
it uses a naive but fast trick to select 4:4:4 or 4:2:0 according to the image data — if 4:2:0 is picked, another heuristic could adjust some internal lib's stuff or wavif's settings/alpha optimization. the transform would be done using libsharpyuv which often give nice results (at the cost of speed/mem)
| infile | outfile | res | time |
|---|---|---|---|
| 1,79 MB | 530,35 KB | 4:4:4 | 0,35s |
| 459,35 KB | 38,08 KB | 4:4:4 | 0,08s |
| 24,92 KB | 14,26 KB | 4:4:4 | 0,07s |
| 73,73 KB | 20,24 KB | 4:2:0 | 0,05s |
alpha
it does not only quantize data where the alpha value would be zero, it also changes the image data itself to make it more compressible. most of the time, this would affect metrics results, filesize and speed positively but not always. the demo use exact same settings but 'alpha optimizer' turned on/off
| opt | infile | outfile | dssim | butteraugli | time |
|---|---|---|---|---|---|
| off | 423,42 KB | 72,35 KB | 29361 | 1.77 | 0,09s |
| on | 423,42 KB | 54,58 KB | 28989 | 1.75 | 0,09s |
other stuff
based on pingo, wavif inherits some of its features
- it converts PNG/JPG to sRGB using the color profile (including CMYK)
- transforms — resize (partial resampling for huge JPG), selective sharpness, grayscale or remove transparency
- filehandler — auto-multithreading/processing, folder support, drag-and-drop
demos are done using wavif 0.25 on Intel(R) Core(TM) i5-12400 (6C, 12T), 2.50 GHz — 16,0 Go DDR4 RAM — WD Black SN750 1 To — Windows 11 Pro. the libaom was compiled with SSEx/AVX