Originally Posted by Brokk1
Into this mix I will throw my problem. I was searching for a thread that touched on my issue and this one seems pretty close.
As with many folks posting here, I have an older receiver with AC-3 (now called Dolby Digital) 5.1 support, via optical or coax. No DTS. No HDMI.
I have a bluray player with an optical output. Great. I send that to my receiver, while HDMI goes to the HDTV.
Lord of the Rings, bluray extended edition. Opening menus pops up with wonderful full 5.1 surround sound. Movie starts, and the sound track is two channel PCM stereo. What gives?!?
LoTR bluray, has as it's main sound track DTS-HD MA. My receiver doesn't support that (only optical), so it drops to the default of PCM 2 channel stereo over optical. There is no option on the bluray movie to choose a different soundtrack for English. I could watch it in spanish with 5.1 Dolby... not going there.
So while I can agree with all the previous posters about lossless audio and lossy audio and it might not be worth the money to go with lossless... The honest truth is that watching this movie sucks because my receiver doesn't support the format it wants to send. I was able to tweak my blueray player settings, to send more than just 2 channel via PCM but now it won't send dolby digital signals anymore. Everything it sends is PCM, which is underwhelming. Honestly, it's a PITA to have to navigate to the player's menu to adjust the sound before each movie, and that's assuming I even know what the movie will default to for a sound track. If I could tell it to convert everything to AC-3 that would solve all my issues, but that is not an option it provides.
I was hoping a product like this would solve my problem:http://www.monoprice.com/Product?c_id=101&cp_id=10110&cs_id=1011002&p_id=5557&ref=cj
But I can't get a straight answer out of monoprice about what is sent down the optical line when you have DTS-HD MA coming through the HDMI cable. Any thoughts?
To answer your question you have to understand how multichannel audio was used on DVD versus Blu-Ray. Remember your receiver was likely (you didn't post the model number) built at a time either when LaserDisc AC3 was in use or DVD Dolby Digital first came out. AC3 is just the non-marketing term for Dolby Digital, so you can use those interchangeably.
When a DVD is mastered, it is required
that the first audio in the soundtrack be either 2.0 channel PCM or Dolby Digital. It may not be DTS despite DTS's efforts, at that time, to include them and exclude Dolby. DTS may only be used as a secondary audio track, which is why you have to select the DTS track on a properly authored DVD.
Advancing 10 years or so to Blu-Ray, both Dolby and DTS proposed new lossless audio codecs for Blu-Ray and HD-DVD (remember that format?). Both codecs had the ability to send out an "original" version of Dolby or DTS for less capable systems. So, Dolby TrueHD would send out Dolby Digital for S/PDIF output and DTS-HD MA would send out the DTS core for S/PDIF output. The way Dolby and DTS handle the S/PDIF output is actually different in that DTS includes the "core" as part of the build-up for DTS-HD MA, while TrueHD includes a separate Dolby Digital encoding with the TrueHD packet, but that isn't relevant here.
What is relevant is that DTS can't drop down to Dolby Digital and TrueHD can't drop down to DTS. There was, at one time, a Toshiba Blu-Ray (may have been HD-DVD) player that would output everything in DTS. That was because the player had a DTS encoder built-in. So, it would take the Dolby Digital signal, decode it and then re-encode it into DTS (actually making the audio worse since it was now double lossy encoded). I know of no player that would output everything in Dolby Digital, since that was the lower bitrate/worse sounding alternative of the two.
DTS and Dolby are separate companies that often don't play well together, so you cannot expect one's decoder to output its rival's format. The only thing that saved you previously was that DVD required Dolby Digital in the first audio track (or 2.0 PCM). This is not true with Blu-Ray.
There are simple ways to solve your problem if
you have multichannel inputs on the back of your receiver. That you haven't mentioned this makes me think your receiver doesn't have those. I had a mid-1990s Yamaha receiver that could only process Dolby Digital (from a LaserDisc) and didn't have multichannel inputs. I liked it but had to sell it when DTS came about. After that I always purchased AVRs that had 6 (or 8) multichannel analog inputs so that, when a new audio format came out, I could process that outboard and send to the receiver.
But, given your receiver must be 15 or so years old, it probably is time to get a replacement or realize that you can only hear multichannel audio if the soundtrack is encoded in Dolby TrueHD. Unfortunately for you, while DTS is no longer being used in the theater prints, the home market has been saturated with DTS-HD MA titles since DTS provided better authoring tools than Dolby (TrueHD seems to only be encodable if you use a Mac). So, in the future I see the gap between DTS-HD MA and Dolby TrueHD to be growing in DTS's favor.
Unfortunately, the box you linked from Monoprice does not have a Dolby Digital encoder in it. And, since you can't get water from a stone or, in this case, Dolby Digital from DTS it will not work for you (again, unless you have multichannel inputs on your receiver). What you really need is a box that would decode DTS into its multichannel PCM channels (stems) and then re-encode that into Dolby Digital and then send that out without any sync issues. While I know how to build that, it would be much more expensive than a new receiver.
Only other things I could suggest would degrade your picture quality (DVD or online streaming), so I would not suggest them. You've invested in a Blu-Ray player to improve your picture quality. Now that the audio is a problem makes it a good time to upgrade the rest of the A/V eco-system. On the plus side, the Blu-Ray high resolution audio codecs are much, much better sounding than Dolby Digital/AC3 (although the better mastering techniques have a large part to do with that, but that is another story).Edited by alk3997 - 12/29/13 at 6:40am