• choco install msys2 -y or get it here
• C:\tools\msys64\msys2_shell.cmd
• pacman -S gcc mingw-w64-x86_64-winpthreads-git mingw-w64-x86_64-libwinpthread-git binutils coreutils yasm git base-devel p7zip
• git clone https://aomedia.googlesource.com/aom && cd aom
• ./configure --target=x86_64-win64-gcc --disable-docs && make -j8 (ryzen need -j16)
• 7z a av1-git-win64.7z *.exe examples/*.exe /usr/bin/msys-2.0.dll /usr/bin/msys-gcc_s-seh-1.dll /usr/bin/msys-stdc++-6.dll
• now you have a portable av1 binaries

tip (to compile newer builds)

• make clean && git pull

Download see https://nwgat.ninja/test-driving-aomedias-av1-codec/