v0.13.0 — a GPL edition, with HEIC through x265
Pre-release
Pre-release
Skidbladnir 0.13.0 is a prerelease of the Tauri app. Copies installed from 0.8.0 onwards will offer it as an update.
Two editions
From this release, every build comes in two editions. They differ only in how they write HEIC, and so in their licence.
Standard (Skidbladnir_*) |
GPL (Skidbladnir-GPL_*) |
|
|---|---|---|
| HEIC encoder | Kvazaar | x265, the better encoder |
| HEIC controls | quality | the full list below |
| Licence of the build | ISC | GPL-3.0-or-later, as a whole |
- The same otherwise: WebP, AVIF, JPEG XL, metadata and HEIC input are identical in both.
- Updates: an installed copy updates only to its own edition. To switch, install the other edition over it.
- Source code: Skidbladnir's own source stays ISC. Because the GPL edition contains x265, this release attaches
Skidbladnir-0.13.0-source.tar.gz. It is the complete source, including the pinned x265, libheif, libde265 and Kvazaar sources that GitHub's own "Source code" download leaves out.
HEIC through x265 (GPL edition)
- Lossless: every pixel is kept exactly, stored as RGB at 4:4:4.
- Chroma: 4:2:0 (what phones write), 4:2:2 or 4:4:4. At 4:4:4, red text and pixel art stay sharp.
- 10-bit (HEVC Main 10): this is how phones store HDR photos. It keeps more precision through the colour conversion, so gradients band less, even from an 8-bit image.
- Speed and tuning: x265's ten speed presets (ultrafast to placebo) and four tunings (SSIM, PSNR, grain, fast decode).
- Expert controls: transform-unit intra depth, adaptive quantisation mode and strength, psy-RD and psy-RDOQ, deblocking with its strength and threshold offsets, and SAO.
- Checks: every one of these is tested. libheif's own
heif-decreads the lossless output exactly, and reads the 4:4:4, 4:2:2 and 10-bit output correctly, on Linux and macOS.
Known gaps
- Transparency: libheif encodes it as a second image, and passes x265's expert controls (quantisation, psy, deblocking, SAO) only to the colour image.
- Placebo: x265's placebo preset cannot encode a transparent image smaller than 32 pixels on a side. Skidbladnir says so and suggests veryslow.
- 12-bit HEIC: not offered by either edition.
- HEVC patents: the standard edition was already in the same position, since HEIC is HEVC either way.
- Unsigned app: the app is not code-signed, and the macOS build has never been launched by a person.