This issue appears to be a regression, as I cannot reproduce it with 1.5:
■ uname -srvmo Linux 5.6.14-arch1-1 #1 SMP PREEMPT Wed, 20 May 2020 20:43:19 +0000 x86_64 GNU/Linux ■ LC_ALL=C ls -lh 1994.mkv -rw-r--r-- 1 userx userx 11G May 17 14:50 1994.mkv ■ LC_ALL=C pacman -Qi imlib2 | grep Version Version : 1.5.1-1 ■ time imlib2_view 1994.mkv Image format not available real 0m0.011s user 0m0.005s sys 0m0.006s ■ sudo pacman --noconfirm -U /var/cache/pacman/pkg/imlib2-1.6.1-2-x86_64.pkg.tar.zst &> /dev/null ■ time imlib2_view 1994.mkv No loadable image real 0m22.759s user 0m0.012s sys 0m4.716s
Thank you for maintaining imlib2. It powers my favorite image viewer (feh).