Creating AVIF or HEIC images with transparency does not work

[Janghou]

Converting PNG files with transparency to AVIF or HEIC does not work.

Transparent parts will render black.

I'm glad converting to and creating AVIF files is supported out of the box in 22.04, but unfortunately transparency seems broken.

See also:
https://askubuntu.com/questions/1411869/creating-avif-or-heic-images-with-transparancy-does-not-work-with-imagemagick-in

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: imagemagick 8:6.9.11.60+dfsg-1.3build2
ProcVersionSignature: Ubuntu 5.15.0-40.43-generic 5.15.35
Uname: Linux 5.15.0-40-generic x86_64
ApportVersion: 2.20.11-0ubuntu82.1
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: ubuntu:GNOME
Date: Tue Jun 28 17:28:32 2022
InstallationDate: Installed on 2020-09-10 (656 days ago)
InstallationMedia: Ubuntu 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731)
SourcePackage: imagemagick
UpgradeStatus: Upgraded to jammy on 2022-04-29 (60 days ago)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Nikita Radchenko (nradchenko)]

The issue is fixed in ImageMagick 6.9.12-68 with commit cc4e5a63, and possibly with some other HEIC related commits from the 6.9.12 branch.

Please consider adding 6.9.12 to backports, or applying HEIC coder changes from 6.9.12 to 6.9.11.

https://github.com/ImageMagick/ImageMagick6/commit/cc4e5a6383961c03d340e0237feedfff83f9af0b