Detecting 2 ch vs 5.1 (AAC) to enable less tanscoding

I Love my ROKU, but they will not support AAC 5.1 ch. I can play anything that is AAC 2 CH just fine, and I don't want to down mux 5.1 to stereo when watching movies. Right now i just Trans-code any AACto AC3 so that I can keep 5.1 but this also affects Stereo AAC which i don't need to trans-code.

I would love to see an added detection of AAC stereo vs AAC multi-channel to enable less trans-coding.