HDMI Audio Return Channel
I ask because the Netflix app on the TV is pretty good. I thought the same version would be on the matching Panasonic 3D Blu-ray player, but it's not. Right now, we use the version on the TiVo or Roku.
Fortunately for you, the AVR-791 and VT25 both support a feature of HDMI 1.4 called Audio Return Channel (ARC), which lets the TV send audio back to the receiver along the HDMI cable that connects them (depicted above in the upper left; think of the "built-in tuner" as the online apps). However, this feature is disabled in the AVR by default. To enable it, you must go into the AVR's HDMI Setup menu and set HDMI Control to On. Also, only the TV's HDMI 1 input has this feature, so be sure to connect that input to the AVR's HDMI output.
For those who don't have a TV and AVR with ARC, you would need to connect an optical digital-audio cable from the TV's digital-audio output to a corresponding input on the AVR, as depicted above in the lower right. Then, when you want to watch Netflix using the TV's app, simply select that input on the AVR.
Your query points out an important but little discussed issue with online appsthe apps for a given service aren't the same from one device to the next, even from the same manufacturer. For example, the Netflix app on the VT25 is different than the one on the Panasonic Blu-ray player you got.
If you have an A/V question, please send it to firstname.lastname@example.org.