Features of JPEG XL that should be tested:
- High bit depth: Test for 8, 10, 12, and 16-bit depths.
- Wide gamut: Test Display P3, Adobe RGB, Rec.2020, ProPhoto RGB, etc.
- HDR: Test tone mapping (PQ/HLG) and gain maps (ISO 21496-1)
- ICC profiles: Test exotic/uncommon use of ICC profiles.
- CMYK: Test using the de-facto standard conversion between sRGB and CMYK.
- VarDCT: Test at least the largest and smallest block sizes, and smaller/larger than allowed by spec if the bitstream can express it.
- Modular mode: Test both lossy and lossless mode.
- Alpha channel: Test with VarDCT and modular mode.
- Progressive Rendering: Align on how browsers should render just the DC data, and whether to support
progressive_dcwhich is even further downsampled. - Lossless Transcoded JPEG: Test basic support.
- Orientation: Test that orientation in codestream is respected and EXIF orientation is ignored.
- Animations: Test basic support.
- Layers: Test basic support.
- JPEG XL art: Support for minimal JPEG XL files using modular mode to produce JPEG XL art (may be sensitive to minor differences in decoders)
Web integration points to test:
<img>,<picture>&<source><video poster><input type=image><embed>,<object>&<iframe><link rel=preload as=image>- SVG
<image> - CSS
background-image,content,image-set(),list-style-image - Canvas (2D, WebGL, WebGPU) including
createImageBitmap()andFloat16Array ImageDecoderAPI
- At least one test in https://wpt.fyi/results/jpegxl for each of the 14 features and 9 integration points listed above.
- Propose a solution (RFC) for testing HDR and wide gamut.
- Scored linearly for the total number of features and integration points covered by tests. Tests that cannot be automated due to infrastructure limitations do not contribute to the score.