Poll: Should Sony use DTS-HD Master Audio or Dolby TrueHD?

[PeterTHX]

Originally Posted by syncguy

DTS core that runs at about 1.5Mbit/s is definitely sounds better than DD core.

No it doesn't. Pick up early Paramount titles for a comparison.

Originally Posted by BozQ

They don't? What do they do with the seperate DD track? 448kbps?

It's a companion track. The TrueHD track is discrete and not built on top of anything. It can have any bitrate like 640, 576, 448, or even 384kbps.

Originally Posted by syncguy

Okay. Anyhow, DTS core sounds better than DD. This may be the reason that people having older amplifiers prefer DTS over DD. Dolby labs could have forced or requested studios to use the highest possible rate.

Again, no it doesn't. People are using DVD comparisons when it doesn't apply with BD. Dolby doesn't request or force the studios to do anything, BD has the space and the bandwidth to easily accommodate a 640kbps track.

[Anthony P]

Originally Posted by LembasBread

If they felt they could sell a few hundred extra copies of a title because it boasted superior audio specs, they would slap a 24/96 Linear PCM track on there.

the issue with PCM is that the numbers grow fast, if it is 5.1 it would need 13.8mbps and if it is 7.1 it would need 18.4mbps. I know you sarcastically said "screw the video" but I don't think even an audiophile would be that callous wrt video.

[syncguy]

Originally Posted by PeterTHX

...
Again, no it doesn't. People are using DVD comparisons when it doesn't apply with BD. Dolby doesn't request or force the studios to do anything, BD has the space and the bandwidth to easily accommodate a 640kbps track.

At least it is my experience that blu-ray DTS core sounds better (in comparison to DD) in few older Yamaha amplifiers.

Dolby labs indeed can force a studio to use a certain specification since use of Dolby logo requires certification. Perhaps, that type of enforcement is not commercially feasible or practical.

[DIY_HD]

Let me see if I understand what you guys are saying. According to what I have read, and given the same sampling rate, disc storage is significantly different. Below is a rough illustration of disc usage by encoding technology.

Dolby Labs
DD=Dolby Digital, THD=True HD

THD=================|DD========|

Digital Theater Systems
Core=DTS Core, MA=HD Master Audio
http://en.wikipedia.org/wiki/DTS-HD_Master_Audio

Core======>MA=======|

Linear Pulse Code Modulation (LPCM)

LPCM===========================|DD========|

The DTS lossless residual track is added to the core and combined by the player or AVR when it is decoded. While the lossless TrueHD and DTSMA tracks are (at least theoretically) bit for bit equivalent, the DTS method requires less disc space to provide both lossy and lossless tracks. That is, the core is a subset of the DTSMA track. This may mean the studio can not fit as much extra material on a disc using TrueHD. I believe it is even more true of an uncompressed PCM track.

This is a minor, technical consideration. I would not buy or not buy a disc which uses one lossless technology over another. All other things being equal, I would favor the DTSMA for it's efficiency.

[BozQ]

Originally Posted by PeterTHX

It's a companion track. The TrueHD track is discrete and not built on top of anything. It can have any bitrate like 640, 576, 448, or even 384kbps.

One question, for DTS-HD (HR and MA), was it enforced that the DTS-Core must be encoded in 1536kbps or were studios allowed to encode in 768kbps too?

Originally Posted by syncguy

Dolby labs indeed can force a studio to use a certain specification since use of Dolby logo requires certification. Perhaps, that type of enforcement is not commercially feasible or practical.

Can they really enforce any rule among the studios on how to use their encoders? Besides, I can't recall any title off the top of my head right now that uses DD any less than 640kbps. I can't say the same for foreign dubs of English films of course.

Originally Posted by DIY_HD

Let me see if I understand what you guys are saying. According to what I have read, and given the same sampling rate, disc storage is significantly different. Below is a rough illustration of disc usage by encoding technology.

Dolby Labs
DD=Dolby Digital, THD=True HD

THD=================|DD========|

Digital Theater Systems
Core=DTS Core, MA=HD Master Audio
http://en.wikipedia.org/wiki/DTS-HD_Master_Audio

Core======>MA=======|

Linear Pulse Code Modulation (LPCM)

LPCM===========================|DD========|

The DTS lossless residual track is added to the core and combined by the player or AVR when it is decoded. While the lossless TrueHD and DTSMA tracks are (at least theoretically) bit for bit equivalent, the DTS method requires less disc space to provide both lossy and lossless tracks. That is, the core is a subset of the DTSMA track. This may mean the studio can not fit as much extra material on a disc using TrueHD. I believe it is even more true of an uncompressed PCM track.

This is a minor, technical consideration. I would not buy or not buy a disc which uses one lossless technology over another. All other things being equal, I would favor the DTSMA for it's efficiency.

You're almost there. You got the idea right. Except LPCM should be a longer graph. Because LPCM is simply uncompressed audio. Something which DTHD and DTSHD uses to compress, losslessly. But you're right that it must come with a companion DD Track.

As for disc space effeciency, I think the differences are quite minor to affect video quality that significantly. Seriously, DTS-Core + DTS-HD vs. TrueHD + DD amounts to about the same amount of disc space used.

[ClaytonMG]

Originally Posted by BozQ

One question, for DTS-HD (HR and MA), was it enforced that the DTS-Core must be encoded in 1536kbps or were studios allowed to encode in 768kbps too?


Can they really enforce any rule among the studios on how to use their encoders? Besides, I can't recall any title off the top of my head right now that uses DD any less than 640kbps. I can't say the same for foreign dubs of English films of course.


You're almost there. You got the idea right. Except LPCM should be a longer graph. Because LPCM is simply uncompressed audio. Something which DTHD and DTSHD uses to compress, losslessly. But you're right that it must come with a companion DD Track.

As for disc space effeciency, I think the differences are quite minor to affect video quality that significantly. Seriously, DTS-Core + DTS-HD vs. TrueHD + DD amounts to about the same amount of disc space used.

I am guessing you're right, it shouldn't be too much of a difference. I really wish someone would do a REAL comparison between Dolby TrueHD and DTS-HD MA spacewise. DTS-HD MA doesn't require a seperate audio tracks, however the bitrate must always be 1.5 mbps or higher. Dolby TrueHD can go down to 0 if need be which would save space. I seriously doubt the Dolby Digital campanion track takes up so much space that Dolby TrueHD is considered a space hound compared to DTS-HD MA.

But the DTS-HD MA core has to be 1.5mbps. I am guessing because their 754kbps tracks have the 16khz rolloff feature.

[BozQ]

Originally Posted by ClaytonMG

I am guessing you're right, it shouldn't be too much of a difference. I really wish someone would do a REAL comparison between Dolby TrueHD and DTS-HD MA spacewise. DTS-HD MA doesn't require a seperate audio tracks, however the bitrate must always be 1.5 mbps or higher. Dolby TrueHD can go down to 0 if need be which would save space. I seriously doubt the Dolby Digital campanion track takes up so much space that Dolby TrueHD is considered a space hound compared to DTS-HD MA.

But the DTS-HD MA core has to be 1.5mbps. I am guessing because their 754kbps tracks have the 16khz rolloff feature.

This is taken from Ip Man Blu-ray, produced in Hong Kong.
This film had really unneccessary LPCM, Dolby TrueHD and DTS-HD Master Audio Cantonese soundtrack.

Btw, these specs are courtesy of whoever put this up as one of the reviews on Amazon.com

LPCM Audio Cantonese 6144 kbps 7.1 / 48 kHz / 6144 kbps / 16-bit
DTS-HD Master Audio Cantonese 2681 kbps 7.1 / 48 kHz / 2681 kbps / 16-bit (DTS Core: 5.1 / 48 kHz / 1509 kbps / 16-bit)
Dolby TrueHD Audio Cantonese 1766 kbps 7.1 / 48 kHz / 1766 kbps / 16-bit (AC3 Core: 5.1 / 48 kHz / 640 kbps)
Dolby Digital Audio Cantonese 640 kbps 5.1 / 48 kHz / 640 kbps

I think it's quite safe to assume that DTS-HD and Dolby TrueHD are compressed using the same LPCM track in the disc. In any case, Dolby TrueHD + Dolby Digital combined would result is a slightly smaller file size than the DTS-HD track.

Way too insignificant to affect the video quality drastically if one of the compression methods is chosen.

[Anthony P]

Originally Posted by DIY_HD

Let me see if I understand what you guys are saying. According to what I have read, and given the same sampling rate, disc storage is significantly different. Below is a rough illustration of disc usage by encoding technology.

Dolby Labs
DD=Dolby Digital, THD=True HD

THD=================|DD========|

Digital Theater Systems
Core=DTS Core, MA=HD Master Audio
http://en.wikipedia.org/wiki/DTS-HD_Master_Audio

Core======>MA=======|

Linear Pulse Code Modulation (LPCM)

LPCM===========================|DD========|

The DTS lossless residual track is added to the core and combined by the player or AVR when it is decoded. While the lossless TrueHD and DTSMA tracks are (at least theoretically) bit for bit equivalent, the DTS method requires less disc space to provide both lossy and lossless tracks. That is, the core is a subset of the DTSMA track. This may mean the studio can not fit as much extra material on a disc using TrueHD. I believe it is even more true of an uncompressed PCM track.

This is a minor, technical consideration. I would not buy or not buy a disc which uses one lossless technology over another. All other things being equal, I would favor the DTSMA for it's efficiency.

no should be more like


DD==|DTHD=============|

Core======>MA=======|

Linear Pulse Code Modulation (LPCM)

LPCM=============================================|

LPCM does not need DD and is much longer then DTS HDMA or DTHD+DD.
DTS HDMA can be longer or shorter then DD+DTHD*
and you are right DTHD needs DD

* DD, DTS and PCM are constant bitrates so they are fixed. DTS HD MA and DTHD are variable bitrate so in less complicated parts the bit rate is less then in more complicated parts. What happens is that DTHD bitrate can be real small at times while MA will be limited by the DTS core. ON the other hand in really complicated parts DTS MA and DTHD will be almost the same so DTHD will have the DD extra (for example, if a part needs 2mps in DTHD and MA then DTS =2mbps while Dolby=2.5mbps =2mbpsDTHD+.5DD on the other if DTHD=.5 and DD=.5 then Dolby=1mbps<DTS core<=DTS HD MA) to further make things more complicated DD is DD, it can be anything, a studio could decide to give it the best DD@640 but could also decide that anyone that cares will use DTHD so use 440 (like the DVD) or anything else.

[davcole]

Originally Posted by ClaytonMG

Dolby TrueHD can go down to 0 if need be which would save space. I seriously doubt the Dolby Digital campanion track takes up so much space that Dolby TrueHD is considered a space hound compared to DTS-HD MA.

That's the catch! How many times would a TRUEHD track actually go to 0? As srrnhound pointed out earlier in this thread that the noise floor alone would rarely cause the bitrate to drop below 1.5. Also theoretically, even if the TRUEHD rate were 0, if using fullrate DD compared to full bit dts core, the differences would be 640kbs to 1.5mbs, as a minimum for both. I just don't see on the typical film how many times you'd drop under 1mb for lossless, much less 1.5 and DTSMA can do 1.5 alone, whereas TRUEHD must do whatever the minimum is for lossless AND add the companion 640kbs track.


I don't think on WATCHMEN, that Warners upped the bitrate just to see 24bit light up on screen, but because they don't have to worry about a companion track.

[PeterTHX]

Originally Posted by BozQ

One question, for DTS-HD (HR and MA), was it enforced that the DTS-Core must be encoded in 1536kbps or were studios allowed to encode in 768kbps too?

They have (Suburban Girl is one such title). Keep in mind the MA extension will require more data to make up for the additional compression of the lossy core.

Can they really enforce any rule among the studios on how to use their encoders? Besides, I can't recall any title off the top of my head right now that uses DD any less than 640kbps. I can't say the same for foreign dubs of English films of course.

No, they can't and don't "enforce" anything. Close Encounters and Casino Royale SE companion DD tracks are 448kbps.

You're almost there. You got the idea right. Except LPCM should be a longer graph. Because LPCM is simply uncompressed audio. Something which DTHD and DTSHD uses to compress, losslessly. But you're right that it must come with a companion DD Track.

Except that companion track is half of the core track of the other codec. TrueHD also doesn't depend on reconstructing the data from the lossy track, so it's a lot less DSP intensive, and why many gen-1 BD players just needed a simple firmware update to decode it.

As for disc space effeciency, I think the differences are quite minor to affect video quality that significantly. Seriously, DTS-Core + DTS-HD vs. TrueHD + DD amounts to about the same amount of disc space used.

Roughly.

[PeterTHX]

Originally Posted by davcole

I just don't see on the typical film how many times you'd drop under 1mb for lossless, much less 1.5 and DTSMA can do 1.5 alone, whereas TRUEHD must do whatever the minimum is for lossless AND add the companion 640kbs track.

A good example is Gran Torino, a fairly quiet film.

If you look at the spec thread you'll find plenty of TrueHD tracks that don't take a lot of overall (avg) bitrate even when you factor in a companion track.

[syncguy]

Originally Posted by BozQ

Can they really enforce any rule among the studios on how to use their encoders? Besides, I can't recall any title off the top of my head right now that uses DD any less than 640kbps. I can't say the same for foreign dubs of English films of course.

Dolby labs cannot enforce how studios run their encoders, however, Dolby labs can stop a studio using Dolby (double-D) logo if the track is not encoded to Dolby specifications. If Dolby lab is not satisfied, a track cannot be called "Dolby Digital" or "Dolby True HD". Anyhow, it may not be commercially viable for Dolby labs to enforce rules on studios.

[RocShemp]

Originally Posted by PeterTHX

Nope, that's not it at all.



Watchmen was a box office disappointment, they are also offering a cut not seen in the theater. The Paramont (UK) original cut version is TrueHD BTW.

LOTR is using LaCasa, which did the 7.1 remix and uses DTS.

Originally Posted by davcole

La Casa does the mix, are you trying to say they now determine the encode? I mean they could have just as easily encoded it to TRUEHD 7.1.

I thought their name was Mi Casa. Did they change it?

Originally Posted by BozQ

I can't recall any title off the top of my head right now that uses DD any less than 640kbps.

The region A release of JCVD is in 448kbps Dolby Digital.

[PeterTHX]

Originally Posted by RocShemp

I thought their name was Mi Casa. Did they change it?

Yep, it's Mi Casa.

Too much Spanish!

[Tok]

Really the only advantage of the dts system is for legacy users since most releases use the full rate of the legacy lossy core. BUT some releases have used the 754kbps for the core. But by the time the MA extension data is added the datarate is the same as if a 1509kbps core was used.

The companion DD track with TrueHD can be whatever rates the of the original DD spec. As some have found, some studios are just reusing their DVD 448kbps DD encodes.

DD @ 640kbps is pretty much equal to dts @1509kbps. The lossy coding systems are completely different therefore you can't just assume that the higher data rate is better. dts on DVD is pretty much dead now.

Personally I don't care which one is used. I have been equally impressed with each system in my HT. But I do have a lot more respect for Dolby since they have been involved in a number of ground breaking technologies in audio improvements.

Like others have pointed out THD requires much less processing power for decoding, but this is becoming less of an issue as DSPs have become more powerful.

One thing though that I am concerned about and it not necessarily related specifically to one format or another is:
Players that internally decode are NOT capable of mixing the lossy secondary audio with the LOSSLESS tracks meaning if secondary audio is used, the lossy cores are relied upon. I thought the whole point of having these decoders in players was so mixing could be done internally with the new lossless codecs.

Currently I believe the PS3 is the only player using the lossless tracks when mixing with secondary (PiP or audio commentary) audio.

[ClaytonMG]

Originally Posted by davcole

That's the catch! How many times would a TRUEHD track actually go to 0? As srrnhound pointed out earlier in this thread that the noise floor alone would rarely cause the bitrate to drop below 1.5. Also theoretically, even if the TRUEHD rate were 0, if using fullrate DD compared to full bit dts core, the differences would be 640kbs to 1.5mbs, as a minimum for both. I just don't see on the typical film how many times you'd drop under 1mb for lossless, much less 1.5 and DTSMA can do 1.5 alone, whereas TRUEHD must do whatever the minimum is for lossless AND add the companion 640kbs track.

It might not drop to 0 very often, but I have seen it in the 800kbps range quite a bit which is a pretty big difference between that and 1.5.

Originally Posted by davcole

I don't think on WATCHMEN, that Warners upped the bitrate just to see 24bit light up on screen, but because they don't have to worry about a companion track.

I am actually curious about this. Did WB do their own encode of the audio or was it done someplace else?

[RocShemp]

Originally Posted by PeterTHX

Yep, it's Mi Casa.

Too much Spanish!

That's okay. You guys confused me and actually had me checking my LOTR DVDs. :lol:

Originally Posted by CraigW

Currently I believe the PS3 is the only player using the lossless tracks when mixing with secondary (PiP or audio commentary) audio.

Doesn't the new Oppo handle it that way as well?

[Tok]

Originally Posted by RocShemp

That's okay. You guys confused me and actually had me checking my LOTR DVDs. :lol:



Doesn't the new Oppo handle it that way as well?

Well it is hard to tell in the manuals, but to me it appears that it also suffers from what I have describe above.

[RocShemp]

Originally Posted by CraigW

Well it is hard to tell in the manuals, but to me it appears that it also suffers from what I have describe above.

Well that sucks. Given all the beta testing and promoting it as the be-all/end-all BD player, you would have thought they'd include that option as well.

[Tok]

Originally Posted by RocShemp

Well that sucks. Given all the beta testing and promoting it as the be-all/end-all BD player, you would have thought they'd include that option as well.

Originally Posted by Oppo BD83 manual

1. Secondary Audio: To set the Secondary Audio Program mixing option. Some Blu-ray Discs
contain a secondary audio and video program, such as the director’s commentary. Some Bluray
Discs have a sound effect when you make menu choices. This Setup Menu item allows you
to decide whether to mix the Secondary Audio Program and menu clicking sound into the
primary audio. The options are:
• On – The Secondary Audio Program and menu clicking sound are mixed into the primary
audio. Usually this will cause the primary audio volume to be slightly reduced. High
resolution primary audio will be converted to a normal resolution in order to mix with the
secondary audio.
• Off – The Secondary Audio Program and menu clicking sound are not mixed into the
primary audio and you cannot hear the secondary audio or menu clicking sound. This
setting preserves the highest possible audio quality for the primary audio.

Also there are two discrete tables in the manual depending whether Secondary Audio is on or off. The question is if the normal resolution is implying the lossless track or the lossy cores.