Looking at HEVC as the cause of this issue is possibly going down the wrong path. I recall a couple of threads a week or two ago that mentioned they couldn’t play videos, and the issue was resolved by installing the manjaro-pipewire meta-package, which removes the manjaro-pulse meta-package, and replaces some pulseaudio packages with their pipewire equivalents:
pamac install manjaro-pipewire
or
sudo pacman -Syu manjaro-pipewire
Removing pulseaudio including configuration files and unnecessary dependencies may also be required:
pamac remove -on manjaro-pulse
or
sudo pacman -Rns manjaro-pulse
You may need to reboot for the changes to take effect.
A similar issue & solution were mentioned recently in a Stable Updates announcement thread:
A couple of other threads since then have also had sound/playback issues resolved by replacing manjaro-pulse with manjaro-pipewire.
One thread did also mention that the helvum package also had to be installed: