# dts-HD MA vs.True-HD volume level decoded to LPCM?



## Drudge (Sep 1, 2008)

When dts-HD master audio and Dolby True-HD tracks are decoded in the player and sent out as LPCM are the levels between the two the same?Does the dialog normalization still apply,where dts tracks have to be lowered on average -4dB to be brought in-line with Dolby normalized tracks even when decoded to PCM?

The reason why I ask is I have an older Lexicon MC-12(non hdmi) and have to use the 5.1 analog inputs with the Oppo's outputs for lossless audio and there is no indicator of reference level offset in analog mode on the MC-12.


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## Sir Terrence (Jun 8, 2006)

Drudge said:


> When dts-HD master audio and Dolby True-HD tracks are decoded in the player and sent out as LPCM are the levels between the two the same?Does the dialog normalization still apply,where dts tracks have to be lowered on average -4dB to be brought in-line with Dolby normalized tracks even when decoded to PCM?
> 
> The reason why I ask is I have an older Lexicon MC-12(non hdmi) and have to use the 5.1 analog inputs with the Oppo's outputs for lossless audio and there is no indicator of reference level offset in analog mode on the MC-12.


When DTS-HD Master audio and Dolby TrueHD are transcoded to LPCM, all metadata(dialog norm etc) is then stripped away from the encoded PCM stream. This happens because uncompressed PCM cannot carry a secondary stream like metadata, and why your receiver does not register any dialog norm offset.


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## Drudge (Sep 1, 2008)

Then the volume levels between Dolby and dts lossless audio converted to PCM should be the same.

Thanks Sir T,

If you don't mind me asking,how did you manage to get an Audyssey XT32 equipped Sound Equalizer that I see on your equipment list?Is that one of the perks of being in the Pro world?Those of us on the AVS forum with the Sound Equalizer have been asking Chris if there are any plans to update it from XT to XT32 and they(Audyssey)say that there are no plans to do so:scratch::hissyfit:.


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## JohnJSmith (Apr 25, 2010)

Drudge said:


> Then the volume levels between Dolby and dts lossless audio converted to PCM should be the same.


I don't know if they should be the same, but in my experience they are not.

I just got a PS3 the other day, and I didn't realize it defaulted to LPCM. When I put my first disc in, I immediately noticed the levels were low. Switching the PS3 to bitstream brought the levels back up with my previous BD player.

My old BD player (a $98 Wal-Mart special Magnavox) was similar. The LFE track was much louder with LPCM conversion than without.


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## Sir Terrence (Jun 8, 2006)

Drudge said:


> Then the volume levels between Dolby and dts lossless audio converted to PCM should be the same.


Keep in mind that any dialog norm offset encoded into the Dolby stream will be decoded before transcoding to LPCM. So if the value is -4, it will be transcoded with that value intact, so they won't necessarily have the same volume when converted to PCM



> Thanks Sir T,
> 
> If you don't mind me asking,how did you manage to get an Audyssey XT32 equipped Sound Equalizer that I see on your equipment list?Is that one of the perks of being in the Pro world?Those of us on the AVS forum with the Sound Equalizer have been asking Chris if there are any plans to update it from XT to XT32 and they(Audyssey)say that there are no plans to do so:scratch::hissyfit:.


It is definitely a pro perk


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## Drudge (Sep 1, 2008)

Sir Terrence said:


> Keep in mind that any dialog norm offset encoded into the Dolby stream will be decoded before transcoding to LPCM. So if the value is -4, it will be transcoded with that value intact, so they won't necessarily have the same volume when converted to PCM


So,dialog norm still comes into play.Is there anyway to know if the movie has dialog norm to be able to adjust the overall level when converted to PCM so I can adjust the non dialog norm movies down in volume or the normalized ones up?

It seems to me that the dts-HD MA movies are louder overall than any of the True-HD ones(as few as there are)that I've seen.





> It is definitely a pro perk


Lucky you!:T


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## Sir Terrence (Jun 8, 2006)

Drudge said:


> So,dialog norm still comes into play.Is there anyway to know if the movie has dialog norm to be able to adjust the overall level when converted to PCM so I can adjust the non dialog norm movies down in volume or the normalized ones up?
> 
> It seems to me that the dts-HD MA movies are louder overall than any of the True-HD ones(as few as there are)that I've seen.
> 
> ...


I am going to be honest, I don't worry about dialog norm. I just turn the volume up to whatever is comfortable not matter what value is encoded. 

The only way I can think of to know what value the encoding person set is to stream both codecs and let the receiver do the decoding. This way the offset values are displayed for you to easily see.


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## Drudge (Sep 1, 2008)

Sir Terrence said:


> The only way I can think of to know what value the encoding person set is to stream both codecs and let the receiver do the decoding. This way the offset values are displayed for you to easily see.


Will that work the same way if I just switch my MC-12 to the lossy Dolby Digital downmix track and look at the reference offset on the MC-12 and then use that to determine the volume level or are the mixes going to be different?

For some reason none of the Lexicon units I've owned have ever had the capability to show reference offset for dts,so I can't tell if dts even has dialog normalization present:huh:.


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## Sir Terrence (Jun 8, 2006)

Drudge said:


> Will that work the same way if I just switch my MC-12 to the lossy Dolby Digital downmix track and look at the reference offset on the MC-12 and then use that to determine the volume level or are the mixes going to be different?


This could work because the down mix is a by product of the original mix with the metadata included. The dialog norm offset is the same for both the lossless 5.1 track, and the lossy down mixed two channel track as well. 




> For some reason none of the Lexicon units I've owned have ever had the capability to show reference offset for dts,so I can't tell if dts even has dialog normalization present:huh:.


That is because DTS does not use dialog norm on their encodings. The only movie I can think of that actually used dialog norm on the DTS track was the Watchman.


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## Drudge (Sep 1, 2008)

Sir Terrence said:


> This could work because the down mix is a by product of the original mix with the metadata included. The dialog norm offset is the same for both the lossless 5.1 track, and the lossy down mixed two channel track as well.


I'll use that as an indicator then:T.





> That is because DTS does not use dialog norm on their encodings. The only movie I can think of that actually used dialog norm on the DTS track was the Watchman.


I know that some Denon and I believe Onkyo units as well can tell you if dialog norm is present on dts encoded movies.That's why I always thought it was strange that Lexicon unit never displayed it,but I guess there's no point in having it if only one film uses it.

I think someone was posting a list that showed several dts movies that had dialog norm present by using a Denon or Onkyo unit to indicate it,can't remember where I saw it posted.


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## gdstupak (Jul 13, 2010)

I was wondering what that message was in my Onkyo display. At the start of a movie, every once and awhile the display would show some message about "dialog -1" or something similar but I couldn't find it in any of the set up procedures.
Ah ha.


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## Dimetera413 (Apr 30, 2010)

So having my PS3 convert all audio to PCM is okay? Or should it be DTS HD and Dolby HD, etc.? What is better, i've read about this for a while but could never come up with a clean cut answer on this.


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## Sir Terrence (Jun 8, 2006)

Dimetera413 said:


> So having my PS3 convert all audio to PCM is okay? Or should it be DTS HD and Dolby HD, etc.? What is better, i've read about this for a while but could never come up with a clean cut answer on this.


There is absolutely no audible difference between streaming the codecs to the receiver for decoding, or having the PS3 (or any player) do the decoding and sending a PCM track. No difference period! At Disney we had many, many DBT on this issue, and nobody could distinguish one from the other (and we have some pretty golden eared engineers too). My friend Paidgeek over at Bluray.com told me that the PS3 has the most accurate decoding algorithms that you will see in any player, and they have the benefit of being able to update their algorithms at any time because it is software driven, not SOC(silicon on chips). So you are fine with the PS3 doing the decoding. 

I hope this is as clean cut as it get's :rubeyes:


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## Drudge (Sep 1, 2008)

gdstupak said:


> I was wondering what that message was in my Onkyo display. At the start of a movie, every once and awhile the display would show some message about "dialog -1" or something similar but I couldn't find it in any of the set up procedures.
> Ah ha.


Yes,that is the Onkyo indicating that it adjusted the level down -1dB for that movie or the offset is 1dB.


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## Drudge (Sep 1, 2008)

Sir Terrence,

Since you are in a position to know,the years of speculation that dts was sweetening their lossy mixes on DVD vs.Dolby to make them sound better(sort of a loudness compensation I believe) is that true?


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## Sir Terrence (Jun 8, 2006)

Drudge said:


> Sir Terrence,
> 
> Since you are in a position to know,the years of speculation that dts was sweetening their lossy mixes on DVD vs.Dolby to make them sound better(sort of a loudness compensation I believe) is that true?


Absolutely and positively not! This is as big a joke as Dolby's white paper on the DTS codec. 

What happened was a simple lack of communication between new comer DTS, and a technical set up change developed by Dolby themselves. When DTS first hit the laserdisc, their studio was setting surround levels at 85db per channel. When combined, it actually increased the level of the surrounds to 87db. Dolby had instituted a technical policy to reduce the surrounds to 82db for each channel, which added up to 85db when combined. Nobody told DTS of the technical change, so many DTS Laserdisc's went out with the surrounds too high. Keep in mind, louder always sounds better(unless it leads to distortion or lack of dynamics), and based on that merit alone, a lot of folks thought DTS sound better. Once Dolby informed DTS of the changes, all mixes at that point had the correct 82db for each surround, and the playing field was then leveled again. 

DTS approached Universal in 1998 wanting to do DTS only DVD disc with full bit rate DTS on it. The movies that DTS wanted to use had already been released to DVD with Dolby digital. DTS used a fresh printmaster(not the same as used for Dolby Digital), and created the best mixes they could without altering the source itself. They were not referencing the Dolby tracks, and then sprucing up their own. That rumor was nothing more than a rumor, as there is no truth in it whatsoever. They created the best mix they could, the studio gave a big thumbs up, and it was released to the public. The DVD's did not get the increased 3db on the surrounds like the laserdisc did, so it was basically mix against mix(instead of codec against codec). Analyzing DTS mixes through Sonic Forge software(and comparing to DD mixes) shows some equalization differences here and there, but nothing that "juiced" there mixes when compared to DD. The best example to hear each lossy codec at its best was the special edition of Twister on DVD. You had a 1509kbps DTS, a 448kbps DD track, no dialog norm, and the two codecs were encoded at equal volume. Just switch between them, and no need to adjust for volume differences, there are none. 

IMO, and in the opinion of many audio professionals like me, DTS was the better codec. Even at half bit rate, it sounded richer and more balanced to the ears. At full bit rate(using DBT testing) it is perceptively transparent to the source. Dolby digital cannot make that claim based on the AES white paper that Prof Soldere submitted. Each time the master source was compared to the DD encoding, all listening noticed a drop off in the quality of the audio. 

All of this is best evidenced by the numerous endorsements that DTS has received from the audio community, and the fact their codec was used for music only CD's - something that was not done with DD at any of its usable bit rates. 

All of these rumors were spread online to distract from the fact that a newcomer within the film industry came along and basically out tech'ed a company known for its audio and film technology within the industry. If enough rumors could be spread, it eventually will turn into truth, and Dolby would have made DTS irrelevant within the industry. That did not work so well in the end.


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## Drudge (Sep 1, 2008)

Sir Terrence said:


> Absolutely and positively not! This is as big a joke as Dolby's white paper on the DTS codec.
> 
> What happened was a simple lack of communication between new comer DTS, and a technical set up change developed by Dolby themselves. When DTS first hit the laserdisc, their studio was setting surround levels at 85db per channel. When combined, it actually increased the level of the surrounds to 87db. Dolby had instituted a technical policy to reduce the surrounds to 82db for each channel, which added up to 85db when combined. Nobody told DTS of the technical change, so many DTS Laserdisc's went out with the surrounds too high. Keep in mind, louder always sounds better(unless it leads to distortion or lack of dynamics), and based on that merit alone, a lot of folks thought DTS sound better. Once Dolby informed DTS of the changes, all mixes at that point had the correct 82db for each surround, and the playing field was then leveled again.
> 
> ...


Excellent response on this widely debated myth and the most detailed I've heard yet:T!

Does the lowering of the volume -4dB for dts tracks(if it doesn't have dialog norm) vs. DD with dialog norm still apply when playing back all dts encoded movies including ones on Blu-ray to have and equal dialog reference level?I just want to make sure that that is still a recommended practice.


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## Sir Terrence (Jun 8, 2006)

Drudge said:


> Excellent response on this widely debated myth and the most detailed I've heard yet:T!
> 
> Does the lowering of the volume -4dB for dts tracks(if it doesn't have dialog norm) vs. DD with dialog norm still apply when playing back all dts encoded movies including ones on Blu-ray to have and equal dialog reference level?I just want to make sure that that is still a recommended practice.


Sorry I missed this. DTS lowering of the surrounds is not the same thing as dialog norm. The lowering of the surrounds assures that the combined levels of the surrounds do not exceed the level of the other channels. Dialog norm ensures that programming level remains the same when you switch between channels. IMO it should not be used on DVD's or Bluray's, but Dolby recommends it should. I cannot fathom the reason they do this, but they do.


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## Fastslappy (Dec 23, 2010)

Drudge said:


> Excellent response on this widely debated myth and the most detailed I've heard yet:T!


thank you,
Sir Terrence 

I knew my ears were not fooling me ! I knew DTS is better , but couldn't explain why to friends till now .. !


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## Magyar (Feb 20, 2007)

Sir Terrence said:


> Absolutely and positively not! This is as big a joke as Dolby's white paper on the DTS codec.
> 
> What happened was a simple lack of communication between new comer DTS, and a technical set up change developed by Dolby themselves. When DTS first hit the laserdisc, their studio was setting surround levels at 85db per channel. When combined, it actually increased the level of the surrounds to 87db. Dolby had instituted a technical policy to reduce the surrounds to 82db for each channel, which added up to 85db when combined. Nobody told DTS of the technical change, so many DTS Laserdisc's went out with the surrounds too high. Keep in mind, louder always sounds better(unless it leads to distortion or lack of dynamics), and based on that merit alone, a lot of folks thought DTS sound better. Once Dolby informed DTS of the changes, all mixes at that point had the correct 82db for each surround, and the playing field was then leveled again.
> 
> ...


Well DD was used quiet a bit on DVD-A and or Dual Discs, having said that Dolby never advocated the the use of DD for music only purposes, nor it claimed any transparency in that regard, unlike DTS which made that claim each time it revised it's codec, so I guess legacy DTS was transparent then DTS HD MA is even more as such.onder:

There is also the issue of efficiency, and the fact that DTS's FR isn't flat at 754kbps unlike DD at 448kbps is. But the former is the reason why DD remained the studio's choice as default encode, not to mention DTS was late to deliver their version to be considered by the DVD forum. The full bit rate version just wasn't viable for DVD, which why it's hardly ever used on DVD. Nevertheless DTS turned out to be a good marketing tool to promote certain releases, but all this is not relevant these days we have lossless on BR and it's not important who provides it.


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## Magyar (Feb 20, 2007)

Drudge said:


> Does the lowering of the volume -4dB for dts tracks(if it doesn't have dialog norm) vs. DD with dialog norm still apply when playing back all dts encoded movies including ones on Blu-ray to have and equal dialog reference level?I just want to make sure that that is still a recommended practice.


If the decoding happens in a THX certified receiver or Pre amp this happens automatically, however if you use the analog MCH inputs, then you would have make that correction via the MV. Quiet frankly though unless you watch all movies at calibrated reference levels, I wouldn't worry about those differences, and adjust the MV for each movie for comfort level regardless where the MV is reside at that point.


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## Sir Terrence (Jun 8, 2006)

Magyar said:


> Well DD was used quiet a bit on DVD-A and or Dual Discs, having said that Dolby never advocated the the use of DD for music only purposes, nor it claimed any transparency in that regard, unlike DTS which made that claim each time it revised it's codec, so I guess legacy DTS was transparent then DTS HD MA is even more as such.onder:


DTS claims on Legacy DTS is that it is "perceptively" transparent. In other words, in a DBT you could not tell the master from the encode. They were very successful in proving this, and went out of their way to do so. They went out of their way to prove that point by conducting DBT of their codec, and the master. The never made the claim of total transparency, and that point should be made clear. 

DD was used as a backwards compatible codec, not the primary codec like DTS was. There is a difference. 



> There is also the issue of efficiency, and the fact that DTS's FR isn't flat at 754kbps unlike DD at 448kbps is.


DD relies VERY heavily on global bit sharing, and has to channel join to get to 20khz(in other words, use all the available bits within the system), DTS is -3 at 19khz with no channel joining. Those of us who have access to audio masters, and both companies encoders/decoders know first hand that DTS encodes did less damage to the signal than DD does. Nobody would talk about it except audio professionals outside Hollywood, as Dolby is very politically powerful in Hollywood. 

The mag masters used for encodes on both formats only had a frequency response to 16khz, so being flat to 15khz was not in reality a disadvantage at the time. 



> But the former is the reason why DD remained the studio's choice as default encode, not to mention DTS was late to deliver their version to be considered by the DVD forum.


While I cannot argue DD's efficiency, I would have gladly traded it for better fidelity

Actually Warner was pushing the process of codec testing to benefit Dolby. Nobody within the industry thought that Warner needed to go as fast as they did at that point in the process. So late is a matter of perspective. 




> The full bit rate version just wasn't viable for DVD, which why it's hardly ever used on DVD.


Universal thought it was viable, and apparently the DTS only discs sold very well. 



> Nevertheless DTS turned out to be a good marketing tool to promote certain releases, but all this is not relevant these days we have lossless on BR and it's not important who provides it.


Agreed!


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## DDSDTS (Jun 14, 2011)

This thread helps a lot, i too have a PS3 for BluRay and just picked up a new receiver and when connected via HDMI to the new receiver, and all possible codecs are selected in the sound setup for the PS3, it defaults to PCM. I really didnt know much about PCM until this happened, and I researched it. Up until I got the new receiver, i thought DD and DTS were the best routes , having bitstream sent to the receiver, not knowing any better. But sounds like since the PS3's processing is very good, and stuff like DTS-HD can be decoded by the PS3 and sent via PCM to the reciever and be close to lossless, I will stick with that setting. When I didnt see Dolby Digital or DTS lit up on my receiver, just PCM, when i was running movies and games on the PS3, i thought something was wrong or i needed to set the sound so PCM wouldnt be sent, not realizing PCM was the best way to go, and not realizing that my 5.1 surround tracks were still being decoded correctly, just by the PS3 and not the receiver as I was used to. Forums like this have really helped me catch up on theater tech, and Im glad to be here. Thanks for having me


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## Drudge (Sep 1, 2008)

Welcome aboard,

With Blu-ray there is no real need for Dolby True-HD or dts-HD MA lossless compression and it would have been much better to have just used LPCM instead of adding too all the confusion,but that's marketing for you.:coocoo:


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## grassy (Aug 25, 2011)

JohnJSmith said:


> I don't know if they should be the same, but in my experience they are not.
> 
> I just got a PS3 the other day, and I didn't realize it defaulted to LPCM. When I put my first disc in, I immediately noticed the levels were low. Switching the PS3 to bitstream brought the levels back up with my previous BD player.
> 
> My old BD player (a $98 Wal-Mart special Magnavox) was similar. The LFE track was much louder with LPCM conversion than without.


Yea, I have to agree as my experience has been that I have my ps3 running through my avpa1hd processor and have been listening to movies running through PCM for the last year and only yesterday switched to bitstream and have noticed the difference in my main speakers being louder so to speak. But is it louder or is it just the way it is decoded through my avp for example. I am finding by switching to bitstream the avp does all of the mixing, so in essance the experience of the sound is different. It seems louder but is it? I am interested to hear others experiences and if anyone could explain this to me further I would be pleased to listen. I think due to what you explained with your wal mart special this may be a ps3 issue of the sound being low on PCM. I watched a movie last night and my avp and ps3 experience was definitely different than before and in my case I would say better.


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