Originally Posted by FilmMixer
The hidden DD stream is output if you select TrueHD on a disc in the same way it is on a DTS-HD track inside players that don't support those encodes... it doesn't show up in the audio menu, and the players that cannot deal with TrueHD just ignore the lossless and decode or pass it along.
Granted you don't benefit from a greater encode rate with a DD track at 640, but it's hard to argue that the implementations that Dolby or DTS uses makes one more better suited in regards to backwards compatibility
Difficult argument granted...but that's not likely to stop me.
Backward compatibility may have been the wrong choice of words. SPDIF compatibility was probably a better choice.
Thing is, it gets murky for players that can handle Dolby TrueHD decoding, but obviously need to transcode to something else over SPDIF. The BH200 for one... It supports Dolby TrueHD, so it grabs that track, and outputs PCM 2.0. The hidden, lossy DD5.1 track is/was ignored. No matter the output selection, the 2.0 output was the result of selecting Dolby TrueHD.
With the March firmware update, that changed somewhat:
- SPDIF Primary Pass-thru == 2.0, presumably PCM, but most certainly not DD5.1
- SPDIF DTS re-encode = DTS5.1 (woo hoo)
The A2 also output everything over optical as DTS. Which track did it transcode? The lossy hidden one? Or the lossless one? On one hand it doesn't matter, as the A2 produced proper, multi-channel sound. On the other hand, if they pulled the TrueHD track, it shows that players don't automatically take the lossy one for SPDIF output.
The A3 switched to Dolby Digitial 5.1 over SPDIF. For all Dolby tracks, that obviously meant the hidden track. Easy. For DTS-HD tracks, that meant transcoding the one and only "Core" track.
The advantage of the DTS-HD structure is the "Core" track is not hidden. Consequently there can be no mistake as their is no choice of track to transcode. In my opinion, that makes it better for SPDIF compatibility.