Might this have something to do with it ?
Excerpt from Oppo knowledge base
"In some cases, having HDCD Decoding enabled in both the player and receiver may result in occasional popping or crackling sounds due to HDCD being decoded twice."
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Double drywalled, "Green Glue" treated Theater
GIK acoustic treatment
Epson 8700UB Projecting on a 135" Seymour XD Audio transparent screen
Outlaw 976 Processor
Outlaw 755 amp for Center and all four surrounds
Adcom GFA 555II for Main L & R channels
Behringer EP4000 for two homemade subs
Outlaw Ultra X13 for REAL Sub Bass !
OPPO BDP103, Marantz CD63SE, Denon DP300F
2 Adcom ACE515s for AC current treatment
Newport Theater Director for AC distribution.
Speakers are all built by myself utilizing Dynaudio Drivers
Second room: Yamaha receiver, Musical fidelity X10D tubes, Carver C9 holographic pro.