[PROBLEM] No audio on many AAC files

[mk01]

@IngoVals

now I don't recall if we think about the same so will sumarize:
1) XBMC doesn't support AAC passthrough
2) if XBMC is playing multichannel AAC audio and passthrough is allowed in audio settings, XBMC onthefly recodes AAC to AC3 (keeping all channels) and pushing through passthrough
3) XBMC on RPI is not doing that as it lacks needed cpu power
4) if you use ffmepg to add AC3 audio (as recoded original AAC), you doesn't alter your original media, but you make possible of use multichannel and passthrough. but your media file will be cca 500M bigger (2h movie)