For Mageia Cauldron run the following as root:
dnf config-manager --add-repo https://download.opensuse.org/repositories/home:microchip/Mageia_Cauldron/home:microchip.repo
dnf install ffhevc
For Mageia 9 run the following as root:
dnf config-manager --add-repo https://download.opensuse.org/repositories/home:microchip/Mageia_9/home:microchip.repo
dnf install ffhevc
For Mageia 8 run the following as root:
dnf config-manager --add-repo https://download.opensuse.org/repositories/home:microchip/Mageia_8/home:microchip.repo
dnf install ffhevc