EDID is for more than graphics cards. ANY video source can make use of it. This is why you can plug your BD player into a TV and have it send 2ch PCM audio (or possibly DD to be further sent via SPDIF from the TV to a soundbar) or into an AVR and have it send 7.1 LPCM automatically.

You are correct that a TV doesn't need 7.1 ch LPCM audio but would it get it if that's the EDID it provided indicated it could accept it, or would the AVR punt and just sent 2ch audio anyway? That's why I specifically ask. I'd expect the 976 to be the same as the 975 in this regard, though the safe assumption is that only a 2ch PCM downmix would get sent to the TV.

I prefer Dirac Live because it employs FIR as well as IIR filters to better tackle impulse response. While it is true that you can't optimize both at the same time, you can chose which is more important and and improve both. Dirac Live is one way of doing this.

Now, I could strip off HDMI audio before the pre/pro, process it, and then send it to the pre/pro, but this reduces the pre/pro to a multi channel DAC and volume control. Furthermore, you have to decode bitstream formats ahead of the room processor (because they generally only accept LPCM).

It just so happens that the Oppo BD players can do this AND have an HDMI input who's audio they can decode to LPCM as well. All that would be needed is an HDMI 2.0 switch ahead of it. (2.0a for HDR and 2.0b for metadata like HLG.) But, that's rare for a BD player to do (it was intended to allow new formats to be played on legacy 7.1 pre/pros).

But the 976 has a perfectly good HDMI switch which is why I am interested to see if I can get between the switched and decoded HDMI audio and the DAC and volume control in the digital domain.