[hdmkv]

No. If you play a TrueHD track it will be decoded and downmixed to "number of channels" (from system/audio settings).
If you set "number of channels" to 8 then all 8 channels will be output as PCM.
If the file has multiple tracks you may need to switch (in OSD audio settings) to the TrueHD track.

TrueHD is quite expensive to decode, so is not recommended on Pi1. Pi2 has no trouble with it.

Thanks popcornmix. It appears 3D is only supported for MKV (created by MakeMKV), not in ISO container? Also, in MKV, TrueHD won't have core track unless you add it as a separate track. Is this needed, or only the TrueHD w/o core is fine for both Pi2 decoding or passing as PCM?