dhcgn
commented
1 year ago Thank you for creating this issue and considering the use of JPEG XL in this project.
From my point of view, it is particularly these advantages that are interesting:
- The support of JPEG-XL could reduce the used cloud storage with JPEG-Files (Lossless JPEG transcoding) around 16% to 22% or with JPEG-XL-Files around 50%.
- The cloud storage could be used as an archive, with the support of lossless compression (35% smaller than PNG)
- Future-proof with support for wide gamut and HDR (e.g. 10-bit or 12-bit)
Key Features The JPEG XL codec is designed to allow users to balance three primary criteria for their application:
- high fidelity to the source image (closely matching human perception),
- encoding and/or decoding speed,
- compression ratio (typically 20:1 to 50:1)
Key features of the JPEG XL codec are:
- improved functionality and efficiency compared to traditional image formats (e.g. JPEG, GIF and PNG),
- progressive decoding (by resolution and precision),
- lossless JPEG transcoding,
- support for both photographic and synthetic imagery,
- graceful quality degradation across a large range of bitrates,
- perceptually optimized reference encoder,
- designed for wide gamut and HDR,
- support for animated content,
- efficient encoding and decoding without requiring specialized hardware.
In terms of compression performance, key results are:
- Lossless JPEG transcoding reduces JPEG size by around 16% to 22%.
- Lossless compression (from pixels) is around 35% smaller than (optimized) PNG for 8-bit images, and the improvement is even larger for images with a higher bit depth (e.g. 10-bit or 12-bit).
- JPEG XL is visually lossless at about half the bitrate required by JPEG, i.e. at compression ratios of around 20:1 (1.2 bpp) where JPEG would compress only around 10:1 (2.4 bpp).
- Compared to other image codecs, JPEG XL provides superior compression at a given visual quality.
From White Paper: ISO/IEC JTC 1/SC29/WG1 N100400, JPEG White Paper: JPEG XL image coding system v2.0, 2023.
vishnukvmd
JPEG XL is an efficient format for storing images. However the format is yet to gain adoption: caniuse.com/jpegxl
On the brighter side of things, FFmpeg now supports this codec. Which means we can generate thumbnails and render them on desktop.
There's also an NPM package (jxl-wasm) that provides a CLI for encoding and decoding, which we could reverse engineer. But FFmpeg will be a better bet since we're already using it for transcoding and generating thumbnails for videos.
Rendering these images on mobile will be a challenge until the underlying platforms support them (unless we ship FFmpeg binaries to decode them there as well, which might not happen in the near future). But if there is enough demand, we could allow uploading them from desktop, ignoring the rendering issues on mobile, gracefully handling them with a "This format isn't supported yet." toast.