Originally Posted by wuther
Excuse me if this has been covered before, but is the Blu-ray verson of 2001 a step down because it has uncompressed PCM instead of TrueHD like the HD-DVD version has?
FWIW, the term "uncompressed" when applied to PCM is pure marketing BS. The reality is that it's PCM (Pulse Coded Modulation), which is inherently uncompressed -- that tack on word is totally redundant.
DTS-HD Master and Dolby TrueHD, are both lossless compression formats that typically encode from PCM master tracks. So, basically, when you have PCM encoded on your disk, you are simply bypassing some additional processing, not compromising the sound. In all three formats, the resulting sound is lossless and given identical original PCM masters, the final sound will also be identical (though final recording levels may differ and so comparison requires accurate volume setting to match the levels.)