@ai-ecoverse/wasm-libheif

libheif 1.23.7 for slicc's wasm realm: it decodes HEIF / HEIC (iPhone photos) and AVIF. It has three commands: heif-convert, heif-dec (the same program under libheif's current name) and heif-info. It also ships the static libraries and headers, so other homescoop packages can link it. @ai-ecoverse/wasm-imagemagick-heif does.

Optional package, HEVC inside. HEIC images are HEVC (H.265). This package contains an HEVC decoder, libde265 1.1.3, and HEVC is patent-encumbered: depending on where and how you use it, decoding HEVC may need a patent licence. That's why this package is never part of a base set: install it only if you want it. AVIF is decoded by dav1d 1.5.4 (AV1, royalty-free). There are no encoders (no x265, no aom).

pnpm add -g @ai-ecoverse/wasm-libheif
heif-info IMG_0001.HEIC
heif-convert IMG_0001.HEIC IMG_0001.png          # or .jpg / .jpeg, -q 90 for JPEG quality
heif-convert --with-aux --no-colons portrait.heic p.png   # p.png, p-depth.png, p-urn_com_apple_photo_2020_aux_hdrgainmap.png
heif-convert --with-exif IMG_0001.HEIC IMG_0001.jpg       # IMG_0001.jpg + IMG_0001.exif
heif-convert photo.avif photo.png
heif-convert --list-decoders

• Several images in one file: heif-convert multi.heic out.png writes out-1.png, out-2.png, …, one per top-level image. --with-aux adds the auxiliary images (an iPhone portrait's depth map and HDR gain map).
• Orientation: the HEIF rotation and mirror (irot/imir) are applied, so the output is upright. An iPhone still taken in portrait comes out 3024x4032. Because the pixels are already rotated, the EXIF copied into the JPEG/PNG has its Orientation reset to 1. --with-exif writes the original EXIF, with the camera's Orientation tag, to a .exif file next to the output.
• Output formats: PNG (8 or 16 bit, with alpha when the image has it), JPEG and Y4M. TIFF and WebP output are not built.
• Limits: there are no threads (tiles decode one after another), and no plugins (plugin path: plugins are disabled). Upstream's Emscripten speed shortcut, which turns off HEVC deblocking and SAO, is patched out, so pixels match a native libheif. libheif's default security limits apply, and --disable-limits lifts them.
• Exit status: when an output can't be written (a missing directory, a directory in the way, no permission, a full disk), heif-convert and heif-dec print could not write image and exit 1. Upstream exits 0 there; heif-dec-write-errors.patch fixes that, also for the depth, auxiliary, tile, sequence, XMP and EXIF outputs.

Licences

LICENSE has all four texts, and THIRD-PARTY-NOTICES.md has every library that bin/*.wasm links statically. The sources are the upstream release tarballs pinned (with sha256) in packages/libheif/recipe.yaml, plus the three patches next to it, and build.sh there is the complete build.

Relinking (LGPL)

The programs link libheif and libde265 statically, so the package ships everything you need to relink them against your own build of either library:

• lib/libheif.a, lib/libde265.a, lib/libdav1d.a, include/libheif, include/libde265, include/dav1d and lib/pkgconfig/*.pc;
• share/libheif/relink/: the application objects (heif-dec.a, heif-info.a, libheifio.a), the other static libraries they use (libpng16.a, libjpeg.a, libz.a, libslicc-gaps.a, libslicc_cred.a), the slicc link flags (ldflags.txt, with every --js-library they name in js/) and relink.sh.

With Emscripten 4.0.23 (emcc on PATH):

cd node_modules/@ai-ecoverse/wasm-libheif
bash share/libheif/relink/relink.sh /tmp/relinked \
  /path/to/your/libheif.a /path/to/your/libde265.a   # defaults: lib/*.a
cp /tmp/relinked/heif-dec* /tmp/relinked/heif-info* bin/

Build the replacement libraries like build.sh does: emcmake cmake, static, -fexceptions, libheif with -DHOMESCOOP_NO_EMBIND, -DENABLE_PLUGIN_LOADING=OFF and -DENABLE_MULTITHREADING_SUPPORT=OFF. ladder-pr runs this relink on every build and checks the relinked heif-dec against host libheif (cert/lib/relink-check.mjs).

To link libheif into your own program: PKG_CONFIG_PATH=$PWD/lib/pkgconfig pkg-config --static --cflags --libs libheif gives -lheif -lde265 -ldav1d -lz. Link with -fexceptions.

Tests

packages/libheif/cert runs under slicc-kernel. It covers real iPhone files (an iPhone 13 Pro Max still, and an iPhone 13 Pro portrait with its depth map and HDR gain map), libheif's two-image example and an AVIF, odd sizes (451x461, 1x1, 1023x769 at 16 bit), a rotated file, and corrupt input. Every PNG is compared sample by sample with references generated before this release with Homebrew's libheif 1.23.6. Most outputs are bit-identical to the host's. In one, libheif's example.heic image 1, 35 of 3,279,360 samples differ by 1, and the cert allows at most 1 per sample on at most 0.01% of samples, with each such sample listed in cert/fixtures/references.json. Sources and licences of the sample files are in cert/fixtures/fixtures.json.

Since 1.23.7, heif-info can list metadata from a truncated file without decoding its image. Use heif-convert to validate decoding: the cert requires the truncated fixture to fail with an out-of-bounds extent error and no output.