Well, that was entertaining for sure. I see the issue. The Yamaha has no digitial inputs and only a Discrete 5.0 analog input for multichannel audio. In the pic posted above, the front channels were in the wrong inputs for 5.0 and should have been in the LD/TV MAIN inputs in the 5CH DISCRT INPUT section. The Fronts were connected to the FRONT IN internal amp ports. If not using an external amp connected to the FRONT OUT ports, there should be no wires connected to the FRONT IN and the jumper bars need to be reinserted to connect the FRONT IN and FRONT OUT to use the internal amps.
As for the MAIN DISCRT INPUT, it is 5.0 NOT 5.1. This means the FRONT channels will need to be set at LARGE from the Realtek with NO subwoofer assignment. So, 5.0 out to 5.0 in. Now, setup properly, you will have no sound processing in the Yamaha. It will simply act as a five channel amplifier with volume adjustment. All processing will take place at the other end. Welcome to the forums and enjoy!