I ran into a problem.
As stated in the description, the roon (on core) MQA Decoder stops working when procedural EQ is activated. When I simply turn off the procedural EQ, it works fine.
Input: Tidal MQA
Core: ROCK on NUC7i7
Output: HDMI out of the ROCK named above
Device Settings: “No MQA capabilitys”, MQA Enable Decoder - checked yes, so switch is blue.
DSP(what is enabled): Headroom 3db, SRC (to max SR =96KHz), Procedural EQ (Channel mapping),
In my procedural EQ I channel mapped the front channels to Surround and Surround Rear channels.
We replicated your setup using ROCK running on a NUC connected to an HDMI A/V receiver. I was able to successfully playback MQA and 48kHz MP3 content. The Signal Path looked like this
Based on your symptoms, my hunch is that your audio device is struggling to accept a 24/96 8ch stream over HDMI. We do not have the Meridian HD621 in-house to test, so we can’t say with certainty what formats the device will support in practice. Dropouts and playback failures at high bitrates could be related to cabling, I would suggest changing out the HDMI cable to see if that makes a difference.