I'm sure I saw the option before, but I can't find it in the "Settings/System/Audio" any more. From the screenshot, it seems the options are hidden. How can this happen?
It is only visible if the system has a pt capable device.
Weird. I didn't change device since I saw it last time. The device is AFTV 2.
I found the problem. When I connect a bluetooth stereo earphone, the option disappear, if I disconnect it, the option appear again. Is this behavior expected?
Yes that's expected behaviour as the Audiotrack sink will switch to the bluetooth earphone which will not support passthrough audio.