Hi,

The multichannel analogue inputs involve a DA conversion from the Oppo and another AD conversion into the Meridian processor. By setting the player to output PCM on the HDMI output we save doing that conversion.
The HD621 separates the audio and video components.

Brian

Main: G65, MD600 Sooloos, MC200 Roon Core, MS600, 210, 218, UHD722, DSP5200SE, DSP5200HCSE, M6 & DSW.2
System 2: AC200 MS200, WiiM Pro+, M6.
Other: DSP5000 (96/24v1), DSP3300.