Originally Posted by bigdaddy999
Reposting as I didn't see the note about putting audio questions here.
I ran into the first situation where I got a Blu-Ray that did not have an option to output DD5.1, DTS OR PCM to my Anthem D2 5.1 system. The Anthem is old, but only does DD5.1 / DTS. So any new stuff that isn't dd5.1 or DTS is downconverted from my Panasonic DMP-BD85 blu-ray to PCM which has been fine. The GREEN BOOK blu-ray offered only ATMOS and no PCM option, so I watched it in French with DD5.1 and subtitles. There was no other English soundtrack on the disc.
So I need help undestanding my options, assuming this might be the future of codecs on blu-rays. If I upgrade the blu-ray player to a current model, will it do a the job of decoding/downmixing. say ATMOS to DD5.1 or DTS? Or will I have to update the Anthem as well, which I really don't want to do. Will blu-ray players do this for current codecs? I'm trying to "future proof" as much as I can w/o spending a ton.
OR - just thinking about it now that I wrote this - did I have a PCM track, but had to switch the player to output that to the Anthem manually, and it was there after all?
Selection of Bitstream vs LPCM output when you have told the disc to play a Bitstream track and the player to use Bitstream output should be automatic in the player -- part of the "HDMI handshake" which negotiates the format to send across the HDMI cable according to what the source device is playing and the receiving device can handle. Similarly, down mix of tracks with more than 5.1 channels of content to 5.1 should also happen automatically in the source player if the receiving device can't handle that larger number of channels. Again part of that automatic handshake. Lastly, the "lossless" Bitstream formats (e.g., Dolby TrueHD and DTS-HD MA) are always paired on disc with a "compatibility" track -- DD 5.1 or DTS 5.1 -- in case you aren't connecting to a device which can accept the full TrueHD or DTS-HD MA Bitstream. And once again, the player automatically selects to send the compatibility Bitstream track, instead of the original lossless Bitstream, whenever that is necessary.
An Atmos track is actually a Dolby TrueHD 7.1 track with extra data (for the expected Height speakers) which is ignored unless the track is being processed by an Atmos capable AVR (which your Anthem is not). So what the player is actually playing in this case is a Dolby TrueHD 7.1 track. Again, getting that across the cable to your Anthem should be handled automatically according to what the Anthem says it can accept during the HDMI handshake.
If you tell the player to use LPCM output instead of Bitstream output, it will decode the Atmos track into LPCM 7.1. (There are no Height speaker channels in that.) Furthermore, the LPCM 7.1 will be down mixed as necessary for output if the receiving device can't accept the full 7.1 channels
Since your Anthem D2 can not accept Dolby TrueHD or DTS-HD MA Bitstreams, and can only accept LPCM up to 5.1 channels, you should set your player to LPCM output (even if the track you are playing on the disc is *NOT* an LPCM track). Why? Because the player will then decode the original, lossless Bitstream track (Atmos, which means Dolby TrueHD 7.1 in your case) into LPCM -- followed by down mixing that to LPCM 5.1 for output to match what you D2 can accept. If you tell the player to use Bitstream output, on the other hand, it will send the compatibility (lossy) Bitstream track paired with the original TrueHD or DTS-HD MA track -- i.e., DD 5.1 or DTS 5.1 -- since your Anthem can not accept the original TrueHD Bitstream. The audio decoded into LPCM from the original lossless Bitstream track will be HIGHER QUALITY than what gets included in the compatibility DD 5.1 or DTS 5.1 track. So telling the player to send LPCM output gets you better quality audio.
For details on all of this, see my Blog post here:
Digital Audio 101 (...01010,,,)