The more I read, the more I get confused. Hopefully you (or someone) can help clarify.
a) My Starhub connected to HDMI1-IN on AVR
b) My Blu-Ray connected to HDMI2-IN on AVR
c) My AC Ryan conneted to HDMI3-IN on AVR
d) HMDI-OUT (AVR) is connected to HMDI-IN on TV
Q1. If my SmartTV play videos from Youtube, how to get the sound from the AVR? Connect an OPTICAL wire between TV and AVR?
One way is to use the Optical Cable connection from TV into AVR.
Another way is to use Audio Return Channel feature in the TV and AVR. In AVR, you will need to turn on this ARC feature under HDMI Settings. In TV, you will need to check with TV Manufacturer on how to go about to turn on the ARC Feature.
Q2. You mentioned that I can turn off the AVR at night. So if my AC-RYAN, Starhub and Blu-Ray all playing, which will be seen on TV? Note that the input to the TV now has only 1 input so cannot select SOURCE on TV now.
We were discussing about "HDMI Pass-Through" function in the AVR.
User can bypass the HDMI Video & Audio contents from any HDMI source [eg. Bluray Player, Set-Top Boxes, Game Consoles, etc] into AVR [AVR is on Standby Mode, simple to say is power-off mode] and AVR will send the Audio & Video contents into the TV.
Therefore you do not need to power-on the AVR but you still enjoy the Audio & Video contents from the TV during the night time.
You can only view single source at the one time. Either AC Ryan, Starhub or BD Player at one time.