Support opening and saving L mode AVIF images with libavif >= 1.3.0 by radarhere · Pull Request #9471 · python-pillow/Pillow

radarhere · 2026-03-18T12:55:51Z

Resolves #9465

If an AVIF image is opened with YUV 4:0:0 subsampling, then it is grayscale, so we can use AVIF_RGB_FORMAT_GRAY, instead of AVIF_RGB_FORMAT_RGB, to load it in L mode rather than RGB. Similarly, if the frame being saved is grayscale, using AVIF_RGB_FORMAT_GRAY simplifies encoding within libavif. However, AVIF_RGB_FORMAT_GRAY only become available in libavif 1.3.0, so this feature is only present for that version. As a side effect, this also means that if an RGB image is saved with 4:0:0 subsampling, it will be in L mode after reopening.

Also, if all frames being saved to an AVIF image are grayscale, then if we default to 4:0:0 subsampling (instead of the current default of 4:2:0), then together, an L mode image can be saved and opened again in the same mode.

Co-authored-by: Hugo van Kemenade <[email protected]>

radarhere · 2026-03-26T12:34:06Z

It turns out that Valgrind is raising an error - https://github.com/python-pillow/Pillow/actions/runs/23566085263/job/68628338690?pr=9471#step:5:6558

I've created AOMediaCodec/libavif#3139 to address it.

radarhere · 2026-03-27T00:03:27Z

My PR was merged, but their analysis of the problem is that while the uninitialized value is copied to a local variable, it isn't actually used.

So I suppose there's a choice here.
a) wait for a new release of libavif
b) wait for a new release of libavif, and restrict this feature to that new version or newer
c) avoid waiting and just silence the valgrind error on this test

radarhere · 2026-05-27T05:46:39Z

I'm inclined towards a) wait for a new release of libavif

hugovk · 2026-05-27T06:29:50Z

a) sounds good, we're not in a rush for this.

radarhere · 2026-06-03T14:19:28Z

libavif has now been updated to 1.4.2 - #9652

This PR contains the following updates: | Package | Change | [Age](https://docs.renovatebot.com/merge-confidence/) | [Confidence](https://docs.renovatebot.com/merge-confidence/) | |---|---|---|---| | [pillow](https://github.com/python-pillow/Pillow) ([changelog](https://github.com/python-pillow/Pillow/releases)) | `<12.2.1,>=12.2.0` → `<12.3.1,>=12.3.0` | ![age](https://developer.mend.io/api/mc/badges/age/pypi/pillow/12.3.0?slim=true) | ![confidence](https://developer.mend.io/api/mc/badges/confidence/pypi/pillow/12.2.0/12.3.0?slim=true) | --- ### Release Notes <details> <summary>python-pillow/Pillow (pillow)</summary> ### [`v12.3.0`](https://github.com/python-pillow/Pillow/releases/tag/12.3.0) [Compare Source](python-pillow/Pillow@12.2.0...12.3.0) <https://pillow.readthedocs.io/en/stable/releasenotes/12.3.0.html> #### Removals - Remove non-image ImageCms modes [#9697](python-pillow/Pillow#9697) \[[@radarhere](https://github.com/radarhere)] #### Documentation - Add release notes for SBOM and performance improvements [#9747](python-pillow/Pillow#9747) \[[@radarhere](https://github.com/radarhere)] - Add security release notes [#9741](python-pillow/Pillow#9741) \[[@radarhere](https://github.com/radarhere)] - Add release notes for Python 3.15 beta wheels [#9696](python-pillow/Pillow#9696) \[[@radarhere](https://github.com/radarhere)] - ImageFont can also be used with ImageText [#9597](python-pillow/Pillow#9597) \[[@radarhere](https://github.com/radarhere)] - Additional guidelines for security reports [#9659](python-pillow/Pillow#9659) \[[@wiredfool](https://github.com/wiredfool)] - Fixed typo [#9636](python-pillow/Pillow#9636) \[[@radarhere](https://github.com/radarhere)] - Added CVEs to 12.2.0 release notes [#9591](python-pillow/Pillow#9591) \[[@radarhere](https://github.com/radarhere)] - Revise development support information in README [#9583](python-pillow/Pillow#9583) \[[@aclark4life](https://github.com/aclark4life)] - Add INCIDENT\_RESPONSE.md [#9555](python-pillow/Pillow#9555) \[[@aclark4life](https://github.com/aclark4life)] - Add STRIDE threat model to security docs [#9562](python-pillow/Pillow#9562) \[[@aclark4life](https://github.com/aclark4life)] - Add CVEs to 12.2.0 release notes [#9556](python-pillow/Pillow#9556) \[[@radarhere](https://github.com/radarhere)] - Update README with revised security policy [#9553](python-pillow/Pillow#9553) \[[@radarhere](https://github.com/radarhere)] - Update security policy [#9552](python-pillow/Pillow#9552) \[[@aclark4life](https://github.com/aclark4life)] - Update macOS tested Python versions [#9534](python-pillow/Pillow#9534) \[[@radarhere](https://github.com/radarhere)] #### Dependencies - Update dependency harfbuzz to v14.2.1 [#9720](python-pillow/Pillow#9720) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Update dependency mypy to v2 [#9653](python-pillow/Pillow#9653) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Update dependency cibuildwheel to v4 [#9665](python-pillow/Pillow#9665) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Update github-actions [#9655](python-pillow/Pillow#9655) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Update dependency libavif to v1.4.2 [#9652](python-pillow/Pillow#9652) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Update dependency lcms2 to v2.19.1 [#9651](python-pillow/Pillow#9651) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Update dependency check-jsonschema to v0.37.2 [#9650](python-pillow/Pillow#9650) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Update google/oss-fuzz digest to [`d872252`](python-pillow/Pillow@d872252) [#9614](python-pillow/Pillow#9614) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Update dependency lcms2 to v2.19 [#9609](python-pillow/Pillow#9609) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Update dependency libpng to v1.6.58 - autoclosed [#9608](python-pillow/Pillow#9608) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Update dependency harfbuzz to v14 [#9610](python-pillow/Pillow#9610) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Update dependency mypy to v1.20.2 [#9599](python-pillow/Pillow#9599) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Update github-actions [#9611](python-pillow/Pillow#9611) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Update dependency cibuildwheel to v3.4.1 [#9607](python-pillow/Pillow#9607) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Move dependency versions to single JSON and enable Renovate [#9559](python-pillow/Pillow#9559) \[[@hugovk](https://github.com/hugovk)] - Updated raqm to 0.10.5 [#9557](python-pillow/Pillow#9557) \[[@radarhere](https://github.com/radarhere)] - Update dependency cibuildwheel to v3.4.0 [#9532](python-pillow/Pillow#9532) \[@[renovate\[bot\]](https://github.com/apps/renovate)] #### Testing - Remove matrix.os from benchmark [#9735](python-pillow/Pillow#9735) \[[@radarhere](https://github.com/radarhere)] - Remove references to libavif patch [#9734](python-pillow/Pillow#9734) \[[@radarhere](https://github.com/radarhere)] - Add benchmark tests [#9654](python-pillow/Pillow#9654) \[[@akx](https://github.com/akx)] - Use reshape() instead of setting NumPy array shape directly [#9728](python-pillow/Pillow#9728) \[[@radarhere](https://github.com/radarhere)] - Add dependencies.json to Windows cache key [#9721](python-pillow/Pillow#9721) \[[@radarhere](https://github.com/radarhere)] - Increase AVIF test epsilon for loong64 [#9714](python-pillow/Pillow#9714) \[[@wszqkzqk](https://github.com/wszqkzqk)] - Add colour to Linux and Windows wheel build logs [#9677](python-pillow/Pillow#9677) \[[@hugovk](https://github.com/hugovk)] - Do not test NumPy against Python 3.15 Windows AMD64 wheels [#9674](python-pillow/Pillow#9674) \[[@radarhere](https://github.com/radarhere)] - Run pyroma in `tox -e lint` instead of pytest [#9670](python-pillow/Pillow#9670) \[[@hugovk](https://github.com/hugovk)] - Update Ghostscript to 10.7.1 [#9634](python-pillow/Pillow#9634) \[[@radarhere](https://github.com/radarhere)] - Update free-threading CI [#9625](python-pillow/Pillow#9625) \[[@hugovk](https://github.com/hugovk)] - Increase AVIF test epsilon for riscv64 [#9606](python-pillow/Pillow#9606) \[[@radarhere](https://github.com/radarhere)] - Add Fedora 44 [#9594](python-pillow/Pillow#9594) \[[@radarhere](https://github.com/radarhere)] - Test Ubuntu 26.04 LTS (Resolute Raccoon) [#9587](python-pillow/Pillow#9587) \[[@hugovk](https://github.com/hugovk)] - Skip EPS test\_1 for Ghostscript 10.06.0 [#9588](python-pillow/Pillow#9588) \[[@radarhere](https://github.com/radarhere)] - Catch subprocess.CalledProcessError in test\_grab\_x11 [#9578](python-pillow/Pillow#9578) \[[@radarhere](https://github.com/radarhere)] - Correct feature name [#9542](python-pillow/Pillow#9542) \[[@radarhere](https://github.com/radarhere)] - Skip test if FreeType is not available [#9540](python-pillow/Pillow#9540) \[[@radarhere](https://github.com/radarhere)] - Remove type hint ignore [#9538](python-pillow/Pillow#9538) \[[@radarhere](https://github.com/radarhere)] - Update macOS tested Python versions [#9534](python-pillow/Pillow#9534) \[[@radarhere](https://github.com/radarhere)] - Remove Debian 12 and Fedora 42 from CI [#9530](python-pillow/Pillow#9530) \[[@hugovk](https://github.com/hugovk)] - Remove manylinux2014 and Amazon Linux 2 [#9528](python-pillow/Pillow#9528) \[[@radarhere](https://github.com/radarhere)] #### Type hints - Use NumPy 2.4.6 for mypy [#9705](python-pillow/Pillow#9705) \[[@radarhere](https://github.com/radarhere)] - Update dependency mypy to v2 [#9653](python-pillow/Pillow#9653) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Update putpixel type hint to allow lists in xy [#9585](python-pillow/Pillow#9585) \[[@radarhere](https://github.com/radarhere)] - Remove type hint ignore [#9538](python-pillow/Pillow#9538) \[[@radarhere](https://github.com/radarhere)] #### Other changes - Speed up ImageChops operations [#9738](python-pillow/Pillow#9738) \[[@akx](https://github.com/akx)] - Speed up `Image.filter()` [#9736](python-pillow/Pillow#9736) \[[@akx](https://github.com/akx)] - Speed up `Image.getchannel()`, `Image.merge()`, `Image.putalpha()` and `Image.split()` [#9675](python-pillow/Pillow#9675) \[[@akx](https://github.com/akx)] - Speed up `Image.fill()`, `Image.linear_gradient()` and `Image.radial_gradient()`. [#9737](python-pillow/Pillow#9737) \[[@akx](https://github.com/akx)] - Speed up `Image.resample()` [#9739](python-pillow/Pillow#9739) \[[@akx](https://github.com/akx)] - Speed up `alpha_composite`, `matrix`, `negative`, `quantize` [#9740](python-pillow/Pillow#9740) \[[@akx](https://github.com/akx)] - Remove PyErr\_Clear() of "weird" exceptions [#9730](python-pillow/Pillow#9730) \[[@radarhere](https://github.com/radarhere)] - Check realloc return value [#9722](python-pillow/Pillow#9722) \[[@radarhere](https://github.com/radarhere)] - Add max\_length to PdfStream decode() [#9718](python-pillow/Pillow#9718) \[[@radarhere](https://github.com/radarhere)] - Return early when there is no fill region [#9732](python-pillow/Pillow#9732) \[[@radarhere](https://github.com/radarhere)] - Allow error to be raised if PyDict\_SetItemString fails [#9731](python-pillow/Pillow#9731) \[[@radarhere](https://github.com/radarhere)] - Speed up `Image.blend()` [#9649](python-pillow/Pillow#9649) \[[@akx](https://github.com/akx)] - Raise OverflowError if number of vertices is too large for Path [#9729](python-pillow/Pillow#9729) \[[@radarhere](https://github.com/radarhere)] - Remove unused HSV and LAB matrix conversion from C [#9724](python-pillow/Pillow#9724) \[[@radarhere](https://github.com/radarhere)] - Prevent reusing ImagingDecoderObject.setimage [#9656](python-pillow/Pillow#9656) \[[@Serotav](https://github.com/Serotav)] - Raise ValueError if FPX tile size is not 64px by 64px [#9660](python-pillow/Pillow#9660) \[[@radarhere](https://github.com/radarhere)] - Only clear error if it is BufferError [#9727](python-pillow/Pillow#9727) \[[@radarhere](https://github.com/radarhere)] - Apply XOR mask to 1 and L mode CUR images [#9641](python-pillow/Pillow#9641) \[[@radarhere](https://github.com/radarhere)] - Do not raise error from unknown channel ID when parsing PSD layers [#9644](python-pillow/Pillow#9644) \[[@radarhere](https://github.com/radarhere)] - Raise ValueError if P;2L or P;4L data is truncated in frombytes() [#9725](python-pillow/Pillow#9725) \[[@radarhere](https://github.com/radarhere)] - Embed SBOM into wheels [#9679](python-pillow/Pillow#9679) \[[@hugovk](https://github.com/hugovk)] - Do not set eval() globals in ImageMath.unsafe\_eval() [#9576](python-pillow/Pillow#9576) \[[@radarhere](https://github.com/radarhere)] - Add Tcl/Tk license to wheels [#9663](python-pillow/Pillow#9663) \[[@radarhere](https://github.com/radarhere)] - Ensure map stride is at least one full row of pixels [#9719](python-pillow/Pillow#9719) \[[@radarhere](https://github.com/radarhere)] - Raise OverflowError if text width exceeds INT\_MAX [#9717](python-pillow/Pillow#9717) \[[@radarhere](https://github.com/radarhere)] - Raise error if image modes do not match ImageCms transform modes [#9715](python-pillow/Pillow#9715) \[[@radarhere](https://github.com/radarhere)] - Use int64\_t for text height [#9716](python-pillow/Pillow#9716) \[[@radarhere](https://github.com/radarhere)] - Return if error occurs in Py\_mod\_exec slot [#9712](python-pillow/Pillow#9712) \[[@radarhere](https://github.com/radarhere)] - Add decompression bomb checks to FontFile classes [#9711](python-pillow/Pillow#9711) \[[@radarhere](https://github.com/radarhere)] - If C error is raised, return NULL [#9706](python-pillow/Pillow#9706) \[[@radarhere](https://github.com/radarhere)] - Prevent saving 1 mode images as TGA with run-length encoding [#9709](python-pillow/Pillow#9709) \[[@radarhere](https://github.com/radarhere)] - Raise ValueError if EPS BeginBinary bytecount is negative [#9708](python-pillow/Pillow#9708) \[[@radarhere](https://github.com/radarhere)] - Do not DECREF tuple until tuple items are no longer used [#9707](python-pillow/Pillow#9707) \[[@radarhere](https://github.com/radarhere)] - Do not update NumPy automatically [#9713](python-pillow/Pillow#9713) \[[@radarhere](https://github.com/radarhere)] - Simplified code [#9642](python-pillow/Pillow#9642) \[[@radarhere](https://github.com/radarhere)] - If realloc fails, do not reduce block size [#9702](python-pillow/Pillow#9702) \[[@radarhere](https://github.com/radarhere)] - DECREF PyDict\_GetItemRef result [#9701](python-pillow/Pillow#9701) \[[@radarhere](https://github.com/radarhere)] - Use int64\_t to calculate paste box dimensions [#9703](python-pillow/Pillow#9703) \[[@radarhere](https://github.com/radarhere)] - Calculate JPEG2000 total\_component\_width for each tile in isolation [#9704](python-pillow/Pillow#9704) \[[@radarhere](https://github.com/radarhere)] - Raise ValueError if value is not bytes for TIFF\_BYTE or TIFF\_ASCII tag [#9699](python-pillow/Pillow#9699) \[[@radarhere](https://github.com/radarhere)] - Release Py\_Buffer on error [#9698](python-pillow/Pillow#9698) \[[@radarhere](https://github.com/radarhere)] - Use os.startfile() in WindowsViewer show\_file() [#9692](python-pillow/Pillow#9692) \[[@radarhere](https://github.com/radarhere)] - Validate large filter sizes when initializing RankFilter [#9695](python-pillow/Pillow#9695) \[[@radarhere](https://github.com/radarhere)] - Add decompression bomb check to GdImageFile [#9693](python-pillow/Pillow#9693) \[[@radarhere](https://github.com/radarhere)] - Free image bands when an error occurs while splitting an image [#9694](python-pillow/Pillow#9694) \[[@radarhere](https://github.com/radarhere)] - Check PyList\_Append return value [#9690](python-pillow/Pillow#9690) \[[@radarhere](https://github.com/radarhere)] - Check WebPMuxNew return value [#9689](python-pillow/Pillow#9689) \[[@radarhere](https://github.com/radarhere)] - Check PyCapsule\_New return value [#9691](python-pillow/Pillow#9691) \[[@radarhere](https://github.com/radarhere)] - Do not return negative width for text length [#9623](python-pillow/Pillow#9623) \[[@radarhere](https://github.com/radarhere)] - Add args argument to METH\_NOARGS methods [#9687](python-pillow/Pillow#9687) \[[@radarhere](https://github.com/radarhere)] - Check ImagingNewDirty return value [#9688](python-pillow/Pillow#9688) \[[@radarhere](https://github.com/radarhere)] - Use int64\_t for text width [#9686](python-pillow/Pillow#9686) \[[@radarhere](https://github.com/radarhere)] - Move PyDateTime\_IMPORT inside Py\_mod\_exec slot [#9580](python-pillow/Pillow#9580) \[[@radarhere](https://github.com/radarhere)] - Validate size and rank when initializing RankFilter [#9661](python-pillow/Pillow#9661) \[[@radarhere](https://github.com/radarhere)] - Raise ValueError if insufficient data is read from DDS RGB file [#9405](python-pillow/Pillow#9405) \[[@radarhere](https://github.com/radarhere)] - Correct `IFDRational.__float__()` return value [#9676](python-pillow/Pillow#9676) \[[@nyxst4ck](https://github.com/nyxst4ck)] - Correct length when accessing ImagePath.Path subscript [#9685](python-pillow/Pillow#9685) \[[@radarhere](https://github.com/radarhere)] - Release reference on non-flattened sequence error [#9684](python-pillow/Pillow#9684) \[[@radarhere](https://github.com/radarhere)] - Do not release Py\_buffer until buf is no longer in use [#9683](python-pillow/Pillow#9683) \[[@radarhere](https://github.com/radarhere)] - Do not resize macOS retina screenshots by default [#9266](python-pillow/Pillow#9266) \[[@radarhere](https://github.com/radarhere)] - Add abstract BaseImageFont class [#9595](python-pillow/Pillow#9595) \[[@radarhere](https://github.com/radarhere)] - Cast before multiplying [#9678](python-pillow/Pillow#9678) \[[@radarhere](https://github.com/radarhere)] - Limit radius to half width or height of rounded rectangle [#9561](python-pillow/Pillow#9561) \[[@radarhere](https://github.com/radarhere)] - linesize is always xsize multiplied by pixelsize [#9647](python-pillow/Pillow#9647) \[[@radarhere](https://github.com/radarhere)] - Check annotate\_hash\_table return value [#9572](python-pillow/Pillow#9572) \[[@radarhere](https://github.com/radarhere)] - Catch KeyError when checking mode from PNG IHDR chunk [#9604](python-pillow/Pillow#9604) \[[@radarhere](https://github.com/radarhere)] - Only pass one argument to C expand [#9664](python-pillow/Pillow#9664) \[[@radarhere](https://github.com/radarhere)] - Raise error if declared JPEG2000 marker length is too small [#9666](python-pillow/Pillow#9666) \[[@radarhere](https://github.com/radarhere)] - In \_dump(), use Python PPM save, instead of C [#9566](python-pillow/Pillow#9566) \[[@radarhere](https://github.com/radarhere)] - Raise error consistently from inside ImagingNewArrow [#9571](python-pillow/Pillow#9571) \[[@radarhere](https://github.com/radarhere)] - Simplify `RankFilter.c` check [#9662](python-pillow/Pillow#9662) \[[@radarhere](https://github.com/radarhere)] - Support opening and saving L mode AVIF images with libavif >= 1.3.0 [#9471](python-pillow/Pillow#9471) \[[@radarhere](https://github.com/radarhere)] - \[pre-commit.ci] pre-commit autoupdate [#9648](python-pillow/Pillow#9648) \[@[pre-commit-ci\[bot\]](https://github.com/apps/pre-commit-ci)] - Apply libtiff patch to fix CVE-2026-4775 [#9646](python-pillow/Pillow#9646) \[[@radarhere](https://github.com/radarhere)] - Remove duplicate code [#9640](python-pillow/Pillow#9640) \[[@radarhere](https://github.com/radarhere)] - Switch iOS back to macos-26-intel [#9631](python-pillow/Pillow#9631) \[[@radarhere](https://github.com/radarhere)] - Don't use list as default in PdfParser read\_prev\_trailer [#9629](python-pillow/Pillow#9629) \[[@danigm](https://github.com/danigm)] - Add support for Python 3.15 [#9624](python-pillow/Pillow#9624) \[[@radarhere](https://github.com/radarhere)] - Do not draw line or arc if width is zero [#9589](python-pillow/Pillow#9589) \[[@radarhere](https://github.com/radarhere)] - Use \_accept check in WebP \_open [#9605](python-pillow/Pillow#9605) \[[@radarhere](https://github.com/radarhere)] - Compare dist sizes vs latest PyPI release [#9621](python-pillow/Pillow#9621) \[[@hugovk](https://github.com/hugovk)] - Do not generate SBOM in scheduled run on fork [#9620](python-pillow/Pillow#9620) \[[@radarhere](https://github.com/radarhere)] - Use plugin method directly when saving PDFs [#9547](python-pillow/Pillow#9547) \[[@radarhere](https://github.com/radarhere)] - \[pre-commit.ci] pre-commit autoupdate [#9617](python-pillow/Pillow#9617) \[@[pre-commit-ci\[bot\]](https://github.com/apps/pre-commit-ci)] - Set Renovate prCreation to not-pending [#9616](python-pillow/Pillow#9616) \[[@radarhere](https://github.com/radarhere)] - Raise error if PNG transparency has incorrect type or length when saving [#9536](python-pillow/Pillow#9536) \[[@radarhere](https://github.com/radarhere)] - If PdfParser buffer is memoryview, release it when closing [#9596](python-pillow/Pillow#9596) \[[@radarhere](https://github.com/radarhere)] - Correct integer overflow in 16-bit resampling [#9480](python-pillow/Pillow#9480) \[[@hayatoikoma](https://github.com/hayatoikoma)] - SBOM: Use real versions from dependencies.json [#9593](python-pillow/Pillow#9593) \[[@hugovk](https://github.com/hugovk)] - Restrict SBOM upload to only Pillow JSON [#9598](python-pillow/Pillow#9598) \[[@radarhere](https://github.com/radarhere)] - Generate CycloneDX SBOM at release time via CI [#9550](python-pillow/Pillow#9550) \[[@aclark4life](https://github.com/aclark4life)] - Raise ValueError if ImageOps border has unsupported format [#9426](python-pillow/Pillow#9426) \[[@veeceey](https://github.com/veeceey)] - Unsafe pointer dereference from unchecked Python integer in Tk initialization [#9548](python-pillow/Pillow#9548) \[[@barttran2k](https://github.com/barttran2k)] - Reorder renovate.json [#9565](python-pillow/Pillow#9565) \[[@radarhere](https://github.com/radarhere)] - Add python-pillow GitHub Sponsors to FUNDING.yml [#9563](python-pillow/Pillow#9563) \[[@aclark4life](https://github.com/aclark4life)] - Correct environment URL [#9558](python-pillow/Pillow#9558) \[[@radarhere](https://github.com/radarhere)] - Remove or protect secrets in Actions [#9544](python-pillow/Pillow#9544) \[@[pre-commit-ci\[bot\]](https://github.com/apps/pre-commit-ci)] - Move Homebrew dependencies into Brewfile [#9546](python-pillow/Pillow#9546) \[[@hugovk](https://github.com/hugovk)] - Do not precompute horizontal coefficients if not horizontal resizing [#9543](python-pillow/Pillow#9543) \[[@radarhere](https://github.com/radarhere)] - Fix comparison warnings [#9541](python-pillow/Pillow#9541) \[[@radarhere](https://github.com/radarhere)] - Close PdfParser if error occurs during init [#9539](python-pillow/Pillow#9539) \[[@radarhere](https://github.com/radarhere)] - Drop experimental Python 3.13 free-threaded wheels [#9535](python-pillow/Pillow#9535) \[[@radarhere](https://github.com/radarhere)] - Update github-actions [#9533](python-pillow/Pillow#9533) \[@[renovate\[bot\]](https://github.com/apps/renovate)] </details> --- ### Configuration 📅 **Schedule**: (UTC) - Branch creation - At any time (no schedule defined) - Automerge - At any time (no schedule defined) 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR is behind base branch, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this PR, check this box --- This PR has been generated by [Mend Renovate](https://github.com/renovatebot/renovate).  Reviewed-on: https://git.tainton.uk/repos/webexmemebot/pulls/596 Co-authored-by: renovate[bot] <[email protected]> Co-committed-by: renovate[bot] <[email protected]>

radarhere added 5 commits March 18, 2026 22:28

Simplified code

0fc5897

Do not iterate through all images to check if there is only one frame

0d12ee9

Load frames with 4:0:0 subsampling in L mode with AVIF_RGB_FORMAT_GRAY

049a6ae

If all frames are grayscale, default to 4:0:0 subsampling when saving

87c4305

If frame is grayscale, encode with AVIF_RGB_FORMAT_GRAY

fbcc7af

radarhere mentioned this pull request Mar 18, 2026

Support monochrome AVIF saving and loading #9465

Closed

radarhere changed the title ~~Support opening and saving L mode AVIF images for libavif >= 1.3.0~~ Support opening and saving L mode AVIF images with libavif >= 1.3.0 Mar 19, 2026

hugovk approved these changes Mar 25, 2026

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Comment thread src/PIL/AvifImagePlugin.py Outdated

radarhere and others added 2 commits March 26, 2026 08:49

Merge branch 'main' into avif_gray

81d6913

Use all()

8031782

Co-authored-by: Hugo van Kemenade <[email protected]>

radarhere added the Do Not Merge label Mar 26, 2026

radarhere and others added 2 commits March 27, 2026 11:04

Merge branch 'main' into avif_gray

a01c293

Merge branch 'main' into avif_gray

15f13ef

Increase epsilon for libavif 1.4.2

d51e753

radarhere removed the Do Not Merge label May 28, 2026

Merge branch 'main' into avif_gray

885605c

radarhere merged commit 1854d62 into python-pillow:main Jun 3, 2026
56 of 58 checks passed

radarhere deleted the avif_gray branch June 3, 2026 22:35

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Support opening and saving L mode AVIF images with libavif >= 1.3.0#9471

Support opening and saving L mode AVIF images with libavif >= 1.3.0#9471
radarhere merged 11 commits into
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radarhere:avif_gray

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radarhere commented Mar 18, 2026 •

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