A Guide to Home Theater Audio CODECs

[Maximln]

Boy, is that S550 slow compared to the S370 & it reacts a whole lot different too! There are only 2 options for the HDMI Audio setting. "Auto" & "2 Channel PCM". When it is set to "Auto", it does output 7.1 DTS-HD Master Audio sound automatically which is different from the "Auto" setting on the S370 (I just double checked it to make sure. It still sends lossy 5.1 DTS to the receiver when it is set to "Auto"). And obviously when it is set to "2 Channel PCM" it does just that. Sends only 2 channels of PCM. What the heck is that setting for?? There is also a "Direct" or "Mix" setting for the secondary audio. When it is set to "Direct" (and "Auto" in the HDMI Audio) the 550 sends the 7.1 DTS-HD MA to the receiver BUT when you change it to "Mix", unlike the 370 which still sends the 7.1 DTS-HD MA signal, the 550 sends the lossy 5.1 DTS as evidenced by the receiver AND the onscreen display of the 550 also shows lossy 5.1 DTS. I guess like Big Daddy mentioned, the 550 is not powerful enough to mix the secondary audio AND output HD Audio.

While I was on my mission, I decided to see what the old PS3 does. I had it set to LPCM & it does indeed output 7.1 DTS-HD MA (just for the record, I have the original 160gb PS3 that I got when it 1st came out so from what I have read, will not bitstream HD Audio anyway & I will never admit how much I paid for on ebay... ). I looked for a separate HDMI "Mix" setting but I could not find one. The only one I found was one for an optical connection but no HDMI. I checked on the title page & you do hear the menu noises & it still does output HD Audio. Does that mean when it is set to LPCM, it is powerful enough to mix the primary & secondary audio & does this automatically?

Incidentally, why do the updates take so long?? I haven't turned it on in a while & of course there was update available & it is taking forever to download & install!!

Max

[BIslander]

Originally Posted by Maximln

There is also a "Direct" or "Mix" setting for the secondary audio. When it is set to "Direct" (and "Auto" in the HDMI Audio) the 550 sends the 7.1 DTS-HD MA to the receiver BUT when you change it to "Mix", unlike the 370 which still sends the 7.1 DTS-HD MA signal, the 550 sends the lossy 5.1 DTS as evidenced by the receiver AND the onscreen display of the 550 also shows lossy 5.1 DTS. I guess like Big Daddy mentioned, the 550 is not powerful enough to mix the secondary audio AND output HD Audio.

I believe it decodes TrueHD when set to Mix, but lacks the horsepower to decode dts-MA and mix secondary audio.

While I was on my mission, I decided to see what the old PS3 does. I had it set to LPCM & it does indeed output 7.1 DTS-HD MA (just for the record, I have the original 160gb PS3 that I got when it 1st came out so from what I have read, will not bitstream HD Audio anyway & I will never admit how much I paid for on ebay... ). I looked for a separate HDMI "Mix" setting but I could not find one. The only one I found was one for an optical connection but no HDMI. I checked on the title page & you do hear the menu noises & it still does output HD Audio. Does that mean when it is set to LPCM, it is powerful enough to mix the primary & secondary audio & does this automatically?

Yes, the PS3 does lossless decoding while mixing secondary audio. In fact, there's no way to disable SA.

[Maximln]

I believe it decodes TrueHD when set to Mix, but lacks the horsepower to decode dts-MA and mix secondary audio.

Hmm...I didn't try the TrueHD. DTS-HD MA is that much harder to decode?

Yes, the PS3 does lossless decoding while mixing secondary audio. In fact, there's no way to disable SA.

Wow! I guess it is as powerful as everyone says! I noticed the S370 loads pretty much as quick as the S370. No where near as slow as the S550!

Max

[DRC72]

Originally Posted by BIslander

I believe it decodes TrueHD when set to Mix, but lacks the horsepower to decode dts-MA and mix secondary audio.

I find it odd that it can mix during a True HD track, but can't on a DTS HD track. I would think it would be a simple firmware update?

[Clark Kent]

Originally Posted by Maximln

Hmm...I didn't try the TrueHD. DTS-HD MA is that much harder to decode?

Yes, DTS-HD MA is much tougher for the processor to decode than TrueHD. Many players, to cut costs, use decoding chips that do not have enough raw horsepower.

[Maximln]

Wow! I guess it is as powerful as everyone says! I noticed the S370 loads pretty much as quick as the S370. No where near as slow as the S550!

I meant the S370 loads pretty much as quick as the PS3! Not itself!

Yes, DTS-HD MA is much tougher for the processor to decode than TrueHD. Many players, to cut costs, use decoding chips that do not have enough raw horsepower.

That probably did maybe make a little sense a few years ago but I would say its pretty much 50/50 between TrueHD & DTS-HD MA now wouldn't you?

Max

[warrenpereira]

I have several Blu Ray movies and concerts and while I understand that theoretically Dolby True HD, DTS HD MA, and PCM should all sound the same it has been my experience that in most cases PCM sounds better overall and I have heard limitations with the Codecs:

300: The 5.1 PCM sounds great and way better than Dolby True HD. And the Dolby True HD and Dolby Digital sound the same which is disappointing.

TRUE ROMANCE: The Dolby True HD track sounds only barely better than the Dolby Digital which is odd. Maybe it is the Dialog Norm?

BARAKA: The DTS HD MA and Dolby Digital sound the same. Shouldn't the DTS HD MA sound way better?

Appreciate any responses from those who have these films or similar issues.

Thank you!

[Dwayne]

Originally Posted by warrenpereira

I have several Blu Ray movies and concerts and while I understand that theoretically Dolby True HD, DTS HD MA, and PCM should all sound the same it has been my experience that in most cases PCM sounds better overall and I have heard limitations with the Codecs:

300: The 5.1 PCM sounds great and way better than Dolby True HD. And the Dolby True HD and Dolby Digital sound the same which is disappointing.

TRUE ROMANCE: The Dolby True HD track sounds only barely better than the Dolby Digital which is odd. Maybe it is the Dialog Norm?

BARAKA: The DTS HD MA and Dolby Digital sound the same. Shouldn't the DTS HD MA sound way better?

Appreciate any responses from those who have these films or similar issues.

Thank you!

I agree 100%. I have always said that all 5.1 or 7.1 PCM tracks sounds more vibrant, detailed and packed with punch. The DTS Master Audio tracks almost always sounds awesome but every now and then you will find one that is lacking. Almost always I think that Dolby TRUE HD sounds very dissappointing and not much better than standard Dolby Digital Tracks. I have heard a few " but not alot " of Dolby True HD tracks that sounded great but not many. I am no sound engineer but I am a serious audiophile with very demanding ears. I have all of the films and agree but with BARAKA I get blown away every time with the DTS MA scene where they are cutting down the tree and it crashes to the ground.

[BIslander]

Please, let's not turn this into another thread about whether PCM or dts-MA or TrueHD sounds better. There are many, many other threads on the subject. Let's keep this one limited to technical discussions.

[Captainhawk1]

I just got a copy of Close Encounters of The Third Kind and lo and behold if it doesn't have both an option for DTS-HD MA and Dolby TrueHD. I've never faced the dilemma before of having to choose obe over the other so I'm wondering which is the preferred? My receiver can handle either so that's not an issue.

[BIslander]

Give it a try and decide for yourself.

When the source is the same, two lossless codecs must, by definition, produce identical outputs. Otherwise they wouldn't be lossless. TrueHD often plays a little quieter because dialnorm can turn down the master volume. If you simply turn it back up by the amount of the dialnorm reduction, you'll be back to identical outputs.

One other note: some receivers cannot apply the same processing to dts-MA and TrueHD. They may, for example, be unable to use Audyssey room correction when decoding a Master Audio track. But, that's a receiver issue, not a codec difference.

[srrndhound]

Originally Posted by BIslander

One other note: some receivers cannot apply the same processing to dts-MA and TrueHD. They may, for example, be unable to use Audyssey room correction when decoding a Master Audio track. But, that's a receiver issue, not a codec difference.

It is a receiver issue brought about by the difference in DSP resource requirements between the two codecs. HDMA is more computationally intensive than TrueHD. That's also why it took the PS3 an extra 1.5 years to get implemented.

[SDDSfan]

Since we know how lossy works for a 5.1 lossy tracks how would it work for 7.1 tracks. For instance if you were to output dts-ma 7.1 through optical in which you would have the dts core version of the 7.1 track, then you fed it through 7.1 receiver using dts-es decoding would you have a close approximation of actuall 7.1 dts-ma track but lossy?

[Blu-Dog]

Originally Posted by BIslander

Please, let's not turn this into another thread about whether PCM or dts-MA or TrueHD sounds better. There are many, many other threads on the subject. Let's keep this one limited to technical discussions.

(let me crawl under this rock first)

Hey, what's wrong with talking about it?

(i don't think this rock is big enough)

[BIslander]

Originally Posted by SDDSfan

Since we know how lossy works for a 5.1 lossy tracks how would it work for 7.1 tracks. For instance if you were to output dts-ma 7.1 through optical in which you would have the dts core version of the 7.1 track, then you fed it through 7.1 receiver using dts-es decoding would you have a close approximation of actuall 7.1 dts-ma track but lossy?

I don't think so. But, you'll need to hear from someone with considerably more technical knowledge than I possess to get a real answer.

Lots of of these 7.1 releases are mixed using the 5.1 stems and some of them are little more than matrixed versions of the 5.1 originals. So, using a DSP in your AVR would probably be pretty close under those circumstances. ES produces a single rear channel, btw, which gets sent to both rear speakers in a 7.1 system. PLIIx produces stereo rears.

[BIslander]

Originally Posted by Blu-Dog

Hey, what's wrong with talking about it?

Nothing. Just trying to head off the same, old foodfight in this particular thread. So far, so good, since the post you quoted goes back to June.

[Blu-Dog]

Originally Posted by BIslander

Nothing. Just trying to head off the same, old foodfight in this particular thread. So far, so good, since the post you quoted goes back to June.

Took me that long to work up the nerve to say something....

[Captainhawk1]

Originally Posted by Blu-Dog

Took me that long to work up the nerve to say something....

Just to make a point here: under normal circumstances is it even worth an argument? A BD normally has either a DTS HD-MA or a Dolby TrueHD track, not both. So there's no point of reference. The only way you could make qualitative judgment is if you were comparing the same source material. That's why asked about the Close Encounters BD because it's an oddity and you certainly can't proclaim one codec better than the other based on one BD.

Am I missing something, here?

[ramicio]

#11 should say:

"There are no differences between LPCM, Dolby TrueHD, and DTS Master Audio when decoded."

[Big Daddy]

Originally Posted by ramicio

#11 should say:

"There are no differences between LPCM, Dolby TrueHD, and DTS Master Audio when decoded."

Earlier in the post, I wrote Decoded Dolby TrueHD = Decoded DTS HD MA = Uncompressed LPCM. I suppose it does not hurt to add the word decoded again to #11. Thank you.