The obvious culprit is that your player is decoding, and not the receiver. Once the player decodes, there is nothing left to decode for the receiver. Both work fine, but if you have a choice, I recommend the receiver do it.
side note: please disable auto-flagged DRC which happens with TrueHD. It won't usually bother you if you didn't, but Iron Man is a particluarly bad implementation. IIRC, the Pioneer should "remember" the disabled setting, unlike my Onkyo.