DTS-HD vs LPCM

[Anakunda]

Hi!
If a BR disc contains both DTS-HD master audio and LPCM version of same track, which one has wider dynamics, lossles part of DTSHD or LPCM, or are they same?

[nevcairiel]

There is no generic answer to this. Every disc may be different.

[Anakunda]

If so then is there a way to conclude this from Media Info or a tool to compare both as for quality?

[Selur]

If so then is there a way to conclude this from Media Info
no
or a tool to compare both as for quality?
one could simply look at both stream using Audacity or similar so see the wave fronts (this should give some insight into the dynamics) alternatively it should be possible to get some statistical data for the streams using sox (assuming it is build with ffmpeg).
Unless mastered differently (and thus come from different sources) lossless tracks should hold the same information.

[Anakunda]

Thanks. Both formats have same frequency, bit depth and channels. Unless DTS-HD containing some extra audio data to extend the dynamics I consider it indifferent to LPCM then.

[Nexin]

The White paper link [5] doesn't link to a document. Maybe it has been updated with a new name?

Wikipedia: DTS-HD Master Audio (http://en.wikipedia.org/wiki/DTS-HD_Master_Audio)

According to the DTS-HD White Paper,[5] DTS-HD Master Audio contains 2 data streams: the original DTS core stream and the additional "residual" stream which contains the "difference" between the original signal and the lossy compression DTS core stream. The audio signal is split into two paths at the input to the encoder. One path goes to the core encoder for backwards compatibility and is then decoded. The other path compares the original audio to the decoded core signal and generates residuals, which are data over and above what the core contains that is needed to restore the original audio as bit-for-bit identical to the original. The residual data is then encoded by a lossless encoder and packed together with the core. The decoding process is simply the reverse.

[5] DTS-HD Audio: Consumer White Paper for Blu-ray Disc and HD DVD Applications (http://www.dts.com/DownloadDocument.aspx?q=a7beda1e-cfe6-4ca4-b6b2-cda9554bb6a5)

[filler56789]

The White paper link [5] doesn't link to a document. Maybe it has been updated with a new name?

As we all should already know, the Internet is as solid as quicksand :p , therefore why are you so surprised about a bad link in a Wikipedia article? :rolleyes:

http://www.opusproductions.com/pdfs/DTS_HD_WhitePaper.pdf

BTW: Google is not your enemy... yet. :scared:

[Atak_Snajpera]

Hi!
If a BR disc contains both DTS-HD master audio and LPCM version of same track, which one has wider dynamics, lossles part of DTSHD or LPCM, or are they same?

what's the point of having two lossless tracks on the same disc?

[Selur]

marketing :D
- DTS-HD 'sounds' good, since it has 'HD' in it's name ;)
- LPCM is downward compatible (even old audio systems support it)

[nevcairiel]

They don't usually care for providing a LPCM stream for backward compat, since for backward compat they have the "core" DTS.
I'm not sure you would actually see such a disc in the real world. I would be surprised at least.

Might be able to find different releases of the same movie with a DTS-HD track on one disc and LPCM on another, or DTS-HD for one language and LPCM for another (surprisingly i actually have one of these), but the exact same audio stream twice on one disc?

[nautilus7]

There is a disc with the same audio in TrueHD and DTS-HD MA (Close Encounters of the Third Kind) and another with TrueHD and LPCM (Fifth Element, Sony Release). Both are quite old though. I haven't seen anything similar these days.

[SeeMoreDigital]

I'm not sure you would actually see such a disc in the real world. I would be surprised at least.
If you check out Blu-rayStats.com (http://www.blu-raystats.com/Stats/Stats.php), you'll find quite a few. Some even offer 7.1 ;)

[nevcairiel]

How do you filter that page for having both DTS-HD and LPCM of the same language?

[SeeMoreDigital]

How do you filter that page for having both DTS-HD and LPCM of the same language?
Go the the 'Audio' drop-down tab, select the required PCM option, then press on the 'Filter' button.

http://i39.tinypic.com/2ir92bt.png


Cheers

[nevcairiel]

Well that gets my discs with LPCM, but i want discs that have both LPCM and DTS-HD. Wasn't this the entire point of the discussion? :D

[SeeMoreDigital]

Well that gets my discs with LPCM, but i want discs that have both LPCM and DTS-HD. Wasn't this the entire point of the discussion? :D
Sadly that web site does not allow you to select 'two' audio options at the same time. But once you know the titles that contain LPCM audio, you could search those titles again to see if they contain DTS-HD as well ;)

That said, you might have more luck finding both LPCM audio and DTS-HD audio, as well as Dolby TrueHD audio, on dedicated Blu-ray Audio discs...


Cheers

[kolak]

what's the point of having two lossless tracks on the same disc?

Main one:
DTS-HD MA will be in most cases surround track (5.0, 5.1, 7.1 etc), where LPCM will be rather 2.0, but this will be proper 2.0 mix (not some automatic downmix).
2nd reason- compatibility, consumer expectation (some people think LPCM is better than DTS-HD MA), "fake" boost in BD value release by including more audio options.
In case of early BD releases there were also technical issues with authoring software etc.

[Sparktank]

I'm actually really on the fence about what the original intent of the OP was for creating this thread.

Is this for purely technical aspects of the formats and which can hold more dynamics?

Or this about deciding which one to select for live playback to get the most dynamics (in a very blindly fashion)?

If the goal is to start selecting one format over the other (without blind abx listening tests), then I think much more variables to be considered for the arbitrary selection process.

We don't know if the OP wants to use the original discs or remux them and play them off an external device or even stream them in some manner.

Disc playback should be fine, it's just a matter of the receiving sound device that can handle the selected format.
For LPCM, I believe to get full (multichannel >2.0) surround sound PCM playback, an HDMI cable is required; else, a toslink/optic/digital cable will only send a (downmixed...properly downmixed?) stereo signal to the receiver.

The Dolby TrueHD and DTS-HD Master Audio formats can send surround signals, but depending on the receiving device, may only be able to decode/use the "core" elements.
I believe for my ancient Kenwood receiver, playing back on disc with the digital coaxial, the non-LPCM HD formats send multichannel but not as greatly defined as it would if I played back the remuxes on my PC (letting LAV/FFDShow decode and sending the decoded raw audio to the receiver via 6 analogous RCA cables -- headphone jack to stereo (black/red) --- and gives a much more dynamic sense of multichannel surround sound (as it would seem each pair -- albeit analog -- have more reserved bandwidth with only two channels instead of sharing 6 channels in one cable).
My stone-age receiver doesn't seem to indicate any of the new-age branding found on a lot of devices (DTS, TrueHD logo stamps, etc -- although, that's largely related to media file playback/DLNA streaming, etc).

I can't use multichannel (>2.0) LPCM from BD-player to receiver directly as I don't have the supporting hardware so it all gets delivered in stereo (and receiver DSP is required to "recover" some of the surround sound dynamics).

PC to receiver, I've not noticed too much difference between the LPCM and losslessly compressed audio formats (THD/DTSHDMA).

Although, based on all listening sessions I've played with, I've not remuxed the LPCM stream when there was a lossless compressed format available that's designated as the primary audio stream.

A few exceptions are observed where the only lossless format is LPCM can be seen in the North American distribution of Christoph Gans' "Silent Hill" (2006) BD [Canada/Region A/NTSC].
It shows only to have 5.1 LPCM and an AC3@640 track.


My observations (using PC->Recevier):
LPCM vs. Lossless compression formats (TrueHD/DTSHDMA)...
Negligible

LPCM vs. AC3(@xxx bitrate)...
Quite discernible (if you know "where" to listen...when to listen for it).

Then again, if the point is about technical aspects (for various reasons: curiosity, potential encoding options, target marketing, etc), I bow out and leave it to the more technically apt points of interest in the discussion thus far.

You also have to consider how some studios master their discs.
Some do it so poorly that your DVD or VHS will be the best option for anything.

Googling for some reviews is quite handy when you want to know more about how some releases.
The reviewers will always give all audio streams (of the original language) a listen and compare/contrast the differences.
And if it is known a movie has been previously released, they would also compare/contrast with the previous releases on the same content.
While being mostly objective, their personal notes and reception of the content they review don't distract from the overall information you're looking for.