True HD vs DTS-MA vs PCM

[itschris]

What really seperates these formats of surround? Why are they different really? Are the sounds placed in the surround channels under a different methodology or what? And how does uncompressed PCM compare to these? I just got Blu-Ray Black Hawk down and it doesn't have True-HD or DTS-MA... only uncompressed PCM and I'm not really sure how that compares or in what way.

 

[Davemcc]

Sound field stuff generally confuses me, but I am under the impression that uncompressed PCM will give you exactly the same signal as the HD codecs, but they are processed in the player instead of the receiver. I await more knowledgable replies than my own.

 

[AcuDefTechGuy]

I did a little experiment on these 3 formats (on the same BD disc):

http://forums.audioholics.com/forums/showthread.php?t=48770

PCM is Uncompressed and Lossless.

TrueHD & DTS-HD MA are Compressed and Lossless.

All 3 are suppose to be identical to the original master copy.

The only difference I can tell is the actual volume level recorded.

 

[itschris]

I did a little experiment on these 3 formats (on the same BD disc):

http://forums.audioholics.com/forums/showthread.php?t=48770

PCM is Uncompressed and Lossless.

TrueHD & DTS-HD MA are Compressed and Lossless.

All 3 are suppose to be identical to the original master copy.

The only difference I can tell is the actual volume level recorded.

Good info. So all of them have to be passed via HDMI. I thought TrueHD and DTS-MA were formats and PCM was more of the type of transfer, but I guess from what you're saying it's just another format like the other two. So I guess if one of the best sounding discs from reviews that I've read is Black Hawk Down, then what the real need or advantage to having the other two. I mean why bother putting these other formats out?

 

[sptrout]

Good info. So all of them have to be passed via HDMI. I thought TrueHD and DTS-MA were formats and PCM was more of the type of transfer, but I guess from what you're saying it's just another format like the other two. So I guess if one of the best sounding discs from reviews that I've read is Black Hawk Down, then what the real need or advantage to having the other two. I mean why bother putting these other formats out?

Not exactly, the output of all analog audio to digital conversions start out as PCM. Some disks like BHD use this PCM track. TrueHD & DTS HD-MA are codecs that take PCM and convert it to a compressed, but lossless, digital format. In your receiver, the TrueHD & DTS HD-MA are converted back to the origianal PCM. If the source disk is PCM, then that is passed straight through to the receiver's DACs for the final conversion back to analog audio.

Therefore, PCM = TrueHD or DTS HD-MA. The advanage of the two compressed, but lossless, formats are that they save space on the Blu-ray disk vs. PCM, which does take considerably more space.

All three should sound the same when the final audio reaches your ears, but you will read that some prefer one format over the others for their own reasons. I am also sure that if you ask Dobly Labs or DTS they will say that their formats are better - - marketing.

In any case, it should make no difference to you which of the three formats a particular Blu-ray disk uses unless your system cannot not decode one of them (usually DTS HD-MA, which was the last one developed and requires more processing power as I understand it).

 

[AcuDefTechGuy]

I mean why bother putting these other formats out?

As already mentioned, TrueHD & DTS-MA takes up A LOT LESS Disc Space.

With a 50GB BD disc, who cares?

However, it might make a difference on a 25GB BD disc. I guess the 25GB discs are a little less expensive.

Those studio cheap bastards!


The "Red Cliff" 50GB BD contains ALL THREE PCM 7.1, DTS-HD MA 7.1, & TrueHD 7.1 plus Perfect Picture Quality.

 

[itschris]

Consider me educated! Thanks guys. It makes perfect sense now.

 

[jostenmeat]

In any case, it should make no difference to you which of the three formats a particular Blu-ray disk uses unless your system cannot not decode one of them (usually DTS HD-MA, which was the last one developed and requires more processing power as I understand it).

Good post. For MA, its more complex since its actually TWO concurrent bitstreams. An "extension" stream on top of "core". That's what ES is on DVDs as well: extension stream.

What's cool is that the "core" will pass via SPDIF and will get you 1.5mps. That's very nice for those who don't want to buy HDMI yet. If all tracks were actually DTS-MA, rather than having either TrueHD or PCM, I daresay we wouldn't really even need HDMI receivers!!

Also, TrueHD movies are accompanied by the legacy track. Since MA has the "core" already embedded, it is actually even more efficient since there is no need to have an accompanying track. At least for the way things are done today.

Lastly, perhaps thru no fault of Dolby, I hate that DRC is so often flagged automatically, with implementation of dialnorm that makes me rather curious.

So, I guess I must say I prefer DTS-MA.

 

[fmw]

All of these points are more academic than practical. They did a bias controlled test at one of the movie studios and determined that people couldn't hear the difference between them and regular dolby digital. Interesting discussion points but they don't really apply to anything very useful.

 

[ParadigmDawg]

Is there a way to prevent the PS3 from flagging this?

Lastly, perhaps thru no fault of Dolby, I hate that DRC is so often flagged automatically, with implementation of dialnorm that makes me rather curious.

So, I guess I must say I prefer DTS-MA.

 

[Geno]

All of these points are more academic than practical. They did a bias controlled test at one of the movie studios and determined that people couldn't hear the difference between them and regular dolby digital. Interesting discussion points but they don't really apply to anything very useful.

I did some casual listening comparisons between DD and Dolby TrueHD. But honestly couldn't hear much of a difference. I wanted to think that the new codecs were more "punchy" (explosions more 'explosiony') but it was probably my imagination trying to justify the hype that made me buy into BluRay. We're sure suckers for the new stuff, ain't we?

 

[jostenmeat]

Is there a way to prevent the PS3 from flagging this?

I would assume not, except I believe j garcia said something to the extent that he could. He was questioned if he was sure about it, but I think he has yet to report yay or nay.

Someone else is going to see if his Pioneer may be able to do such a thing, after he gets it. My memory is fuzzy. I believe I said that if it could do such a thing, it would score a major point for me towards this brand.

j