I have had an 863 for about 3 years now, and it's worked perfectly for my needs. I just bought an 867 because I needed to have TWO HDMI OUTPUTS, one going to my HDTV (as before, with the 863) to deliver digital video, and the second going to a "downstream audio processor" fed by decoded LPCM over HDMI, with that decoded LPCM delivered to the 867 from my Oppo BDP-83. The idea is that the 867 would simply pass the input LPCM over HDMI, through the 867 and out over HDMI OUT to the downstream connected HDMI audio processor device.
Now with the 863, I never had this new need to deliver LPCM audio over HDMI to the secondary HDMI connected device. I used the preamp output of the 863 to feed the audio processor using analog feeds. With the 867 and the additional HDMI output, I now can theoretically feed the audio processor using HDMI digital (i.e. with LPCM over HDMI).
So in my old setup I had the 863's "HDMI Set" item (in the Option Menu) configured to NOT send any received digital audio further than the 863. I used the HDMI output from the 863 strictly to feed digital video to the attached HDTV, with digital audio being handled "locally" by the 863 itself and delivered to speakers and/or preamp output.
According to the 863's manual, "HDMI Set" is used "to select whether to play back HDMI audio signals on this unit or on another component connected to the HDMI OUT jack on the rear panel of this unit". And the two values are
(a) RX-V863, plays back HDMI audio signals on this unit. HDMI audio signals input at the HDMI input jacks of this unit are not output to the HDMI component connected to the HDMI OUT jack on the rear panel of this unit.
(b) OTHER, plays back HDMI audio signals on another HDMI component connected to the HDMI OUT jack.
In other words, RX-V863 suppresses HDMI input audio from going any further than the 863. OTHER passes on HDMI input audio to the connected downstream device. And it is the downstream device which actually sends back the request to the original input source device for multi-channel or 2-channel stereo digital audio to be delivered over HDMI from source device to the AVR and then on to the downstream device.
But... if in this scenario with OTHER specified (so as to send digital audio out over HDMI OUT) the downstream device requests multi-channel, then the source device WILL send multi-channel and the 863 will simply "pass through" whatever it receives to the downstream device. So if my Oppo sends decoded multi-channel LPCM to the 863 over HDMI, the 863 will send the same decoded multi-channel LPCM out over HDMI OUT to the downstream device, and everything works perfectly.
In contrast, the equivalent setting on the 867 is called "Audio Output" sound in the "HDMI Setup" group. Curiously, the introductory statement is slightly different than it was for the 863 in that it makes specific reference to a TV as the presumed downstream HDMI connected device: "choose whether audio is played back through this unit or through a TV". This is important because no TV's are capable of receiving multi-channel. If they are asked, they will request 2-channel stereo.
Anyway, for each HDMI output (OUT1 and OUT2) there are two settings possible:
(a) OFF, audio is not output through a TV connected via the HDMI OUT jack.
(b) ON, outputs audio through a TV connected via the HDMI OUT jack. When this setting is selected, audio from the external [source] component is output in a format compatible with the TV.
Again, note the reference to "TV" in the description of ON, as if this were the only expected downstream device connectable to the HDMI OUT jack from the 867. And since no TV can accept multi-channel but will only accept 2-channel stereo, that means ON actually forces 2-channel stereo (since this is the only format compatible with the TV). Apparently It doesn't matter that my downstream HDMI connected device is NOT a TV (which can't handle multi-channel but can handle 2-channel stereo), but instead is a digital audio processor that CAN handle multi-channel and in fact want multi-channel.
In fact, it doesn't even matter that there is no TV connected at the other end of either HDMI1 or HDMI2 outputs. Even when only the digital audio processor is connected, the delivered audio from HDMI OUT is always 2-channel stereo!!!
So, the 867 delivers only 2-channel stereo via its HDMI OUT!!! No matter what is the input, the output over HDMI is always 2-channel stereo. Even though the Oppo player is delivering multi-channel LPCM over HDMI input to the 867, the HDMI OUT from the 867 to the HDMI connected digital audio processor is always 2-channel stereo.
Again, in the same setup, the 863 will "pass through" the input HDMI audio to the HDMI OUT jack. Multi-channel LPCM input is sent on through exactly the same way to HDMI OUT, and the downstream device gets it correctly. But with the 867, there is apparently no "pass through". Instead, the only output ever seen from HDMI OUT is 2-channel stereo.
I have a ticket open at Yamaha and hope to get a call back from 2nd-level support on Monday, to explain this anomaly. Why did they change the design in the 867? Is there a workaround or solution, to get true "HDMI pass-through" of multi-channel digital audio over HDMI from input to HDMI OUT? And if not, I will be returning the unit for a complete refund.
This obvious horrible design defect is unacceptable (since it worked perfectly in the 863 but was apparently broken in the 867), but maybe it was corrected in the 871 or other newer models. I didn't want to pay more money than I paid for the 867 (which provided the two HDMI outputs I needed), so we'll see what happens on Monday.