Not sure exactly when this problem started, but I recently noticed on my Fedora 36 machine, that videos would not play unless the sound was muted.

I also started seing the message “snd_hda_codec_realtek hdaudioC0D0: Unable to sync register” in the /var/log/messages.

After doing a bit of rooting around on the Intertubes, I found a fix

echo “options snd-hda-intel probe_mask=1” > /etc/modprobe.d/alsa-base

then reboot.

More info: https://help.ubuntu.com/community/HdaIntelSoundHowto#Playing_with_probe_mask