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post #1 of 44 Old 02-21-2007, 10:17 PM - Thread Starter
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I dont understand how come this format has been almost ignored by many people in favor of either MLP Lossless on DVD-Audio or DSD on SACD. I mean, it allows us to gain much more fair use than the competing formats, and at the same time providing backward compatibility to DTS only capable AVRs...
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post #2 of 44 Old 02-21-2007, 10:36 PM
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The key is copy protection. It is easier to copy and therefore the studios do not like it.
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post #3 of 44 Old 02-22-2007, 04:36 AM
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Quote:
Originally Posted by Coolpplse View Post

I dont understand how come this format has been almost ignored by many people in favor of either MLP Lossless on DVD-Audio or DSD on SACD. I mean, it allows us to gain much more fair use than the competing formats, and at the same time providing backward compatibility to DTS only capable AVRs...

Because MLP Lossless sounds better.
It's that simple.
Good as it is, DTS 96/24 is still a perceptual encoding process, and is still limiting the toital bitrate to 1.509Mb/sec.
MLP Lossless goes up to 9.6Mb/sec, plus is also capable of being downmixed to preset co-efficients, as well as the invaluable ReBit function.
The more complex the mix, the worse DTS will sound as it has to squeeze everything into that 1509Kb/sec.
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post #4 of 44 Old 02-22-2007, 04:45 AM
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Quite a lot of DVD-Audio discs have both MLP Lossless and DTS 96/24. So backwards compatibility with basic DTS players, better playback for DTS 96/24-compatible kit, and best quality playback for DVD-Audio players. Everyone's sorted.

There should be more DTS 96/24 on music video releases though. I can only think of Queen's Greatest Video Hits 1 & 2, and some upcoming David Bowie release off the top of my head.
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post #5 of 44 Old 02-22-2007, 05:49 AM
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Quote:
Originally Posted by KMO View Post

Quite a lot of DVD-Audio discs have both MLP Lossless and DTS 96/24. So backwards compatibility with basic DTS players, better playback for DTS 96/24-compatible kit, and best quality playback for DVD-Audio players. Everyone's sorted.

There should be more DTS 96/24 on music video releases though. I can only think of Queen's Greatest Video Hits 1 & 2, and some upcoming David Bowie release off the top of my head.

This is indeed the best way to author.
You should also include DD 5.1 as well, as DTS is an optional codec for DVD-Video, and Audio Stream 1 must be either DD or LPCM, or you're out of spec.
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post #6 of 44 Old 02-22-2007, 10:37 AM
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Quote:
Originally Posted by Coolpplse View Post

I dont understand how come this format has been almost ignored by many people in favor of either MLP Lossless on DVD-Audio or DSD on SACD.

DTS 96/24 is not 96/24, just more smoke & mirrors from that company. As Neil mentioned, the total bit-rate remains 1509 kb/s, out of which 384 kb/s is set aside for the 96/24 extension packet. Lest anyone think 384 kb/s is a trivial amount, keep in mind that an entire 5.1 channel DD soundtrack used to be encoded at that bit-rate.

So the data available for audible frequencies (up to 24kHz) is reduced in order accomodate lossily compressed frequencies outside the human hearing range (up to 48kHz). The core data (the audible part) is not sampled at 96kHz to begin with; it's 48kHz upsampled to 96kHz during the decoding process.

Personally, I would have preferred if they had applied all the available data to frequencies we can hear. In any case, DTS 96/24 is very different from actual 96/24 audio losslessly packed using MLP.

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post #7 of 44 Old 02-22-2007, 11:13 AM
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Quote:
Originally Posted by sdurani View Post

DTS 96/24 is not 96/24, just more smoke & mirrors from that company. As Neil mentioned, the total bit-rate remains 1509 kb/s, out of which 384 kb/s is set aside for the 96/24 extension packet. Lest anyone think 384 kb/s is a trivial amount, keep in mind that an entire 5.1 channel DD soundtrack used to be encoded at that bit-rate.

So the data available for audible frequencies (up to 24kHz) is reduced in order accomodate lossily compressed frequencies outside the human hearing range (up to 48kHz). The core data (the audible part) is not sampled at 96kHz to begin with; it's 48kHz upsampled to 96kHz during the decoding process.

Personally, I would have preferred if they had applied all the available data to frequencies we can hear. In any case, DTS 96/24 is very different from actual 96/24 audio losslessly packed using MLP.

Sanjay

Sanjay - that's actually not quite right.
The Audio - assuming the source files are actually 24/96 - is not upsampled 48KHz at all.
The rest is pretty much correct though, there is the original Core stream plus extensions. The core is giving every DTS decoder a payload stream of 16/48 or 24/48, depending on source material. The extended frequency response (as is also the case with DTS-ES) carries the payload for the higher frequencies.
How it all works is quite clever - the decoder will always give the best it is capable of automatically.
With the new DTS-HD MAS encoders, we get an additional 2 possibilities:
1 - DTS-HD High Resolution (This gives up to double the usual bitrate)
2 - DTS-HD MAS - this is VBR and true lossless encoding.
Both of these will also still carry the old, original core stream which payloads at 24/48 or 16/48, the rest is again all in the extensions.

And, despite the fact MLP Lossless does sound far better in my mind, DTS-HD MAS will be identical to MLP (Or Dolby True HD as it is now apparently called).
All forms of DTS encoding are audibly superior to Dolby Digital.
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post #8 of 44 Old 02-22-2007, 12:18 PM
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Quote:
Originally Posted by neil wilkes View Post

The Audio - assuming the source files are actually 24/96 - is not upsampled 48KHz at all.

The core data contains audio sampled at 48kHz. How does this become 96kHz upon playback?
Quote:


All forms of DTS encoding are audibly superior to Dolby Digital.

That supposed superiority has never (ever) been demonstrated by any movie studio, music label, or magazine that has put the two codecs head to head in blind listening tests. It's a popular claim amongst DTS enthusiasts, but not even DTS themselves have anything objective to support it (otherwise their marketing department would have been all over it).

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post #9 of 44 Old 02-22-2007, 12:34 PM
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sdurani, this is pretty basic stuff. A decoder interpolates the extra samples, and the extra data encodes the differences between what it would interpolate, and the original data.

For example, given the 96kHz samples 1 4 9 15 17, you might create a 48kHz version of 1 9 18, the decoder interpolates this back to 1 5 9 13 17, and then the extension data contains the differences "-1 +2", which are applied to the interpolated values to adjust it back to 1 4 9 15 17.

Small differences like that compress much better than the basic 48kHz data, and there's not much extra information above 20kHz anyway, so not much space is taken up by the extension data.

This sort of core+extension technique is very common. DTS MA HD uses it too. So does MLP, in a different way - it stores a 2-channel downmix, plus extensions to give you the 5.1 version.

As to whether it's better or not, that's a general 48kHz versus 96kHz argument, nothing to do with DTS.

Another, possibly more significant benefit, is that DTS 96/24 is always 1536kbit/s. Most 48kHz DTS streams are 768kbit/s, so that's an instant win just by having more bitrate.
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post #10 of 44 Old 02-22-2007, 01:11 PM
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Quote:
Originally Posted by sdurani View Post

The core data contains audio sampled at 48kHz. How does this become 96kHz upon playback?

Because the additional information for the higher sample rates is carried not in the core, but in the extensions. As long as my source is from 24/96, the DTS encode - assuming I use the DTS-PSE or the DTS-HD MAS (The only 2 soft encoders capable of 24/96 encoding, as SurCode/Nuendo encoders are not 24/96 compatible) then the encoded DTS stream will give a payload of 24/96 in a 24/96 decoder. This is important, as to get true 24/96 payload, you must use the right encoder as well as the right Decoder. Otherwise you will just get the core, at 24/48 payload.

Quote:
Originally Posted by sdurani View Post

That supposed superiority has never (ever) been demonstrated by any movie studio, music label, or magazine that has put the two codecs head to head in blind listening tests. It's a popular claim amongst DTS enthusiasts, but not even DTS themselves have anything objective to support it (otherwise their marketing department would have been all over it).

Sorry, you're wrong. I proved this recently with several people all at once.
Did the following blind test.
1 - Dolby Digital from 24/48 source
2 - DTS core from 24/48 source
3 - DTS 24/96 from 24/96 source in DTS-PSE encoder
4 - DTS 24/96 from 24/96 source with DTS-HD MAS encoder.
Everyone agreed the following - in order of preference: 4,3,2,1
Dolby came last by a long, long way. Poorly defined detail (or lack of it) in the top end. Overall cloudy sounding. The new DTS encoder is audibly better at 24/96 compared to the older one as well, albeit a subtle improvement.
Dobly Dirgital is just not as good as the marketing says, DTS is much better, more open, more detail, more air in the top end. If you cannot hear this, then your decoders (or the encoded material) has an issue, or is an old version.
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post #11 of 44 Old 02-22-2007, 01:15 PM
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Quote:
Originally Posted by KMO View Post

This sort of core+extension technique is very common. DTS MA HD uses it too. So does MLP, in a different way - it stores a 2-channel downmix, plus extensions to give you the 5.1 version.

That's not right either. MLP only stores a downmix if you tell it to include one, otherwise it is a straight compaction process, complete with verification to ensure the output is bit-for-bit identical to the input.


Quote:
Originally Posted by KMO View Post

Another, possibly more significant benefit, is that DTS 96/24 is always 1536kbit/s. Most 48kHz DTS streams are 768kbit/s, so that's an instant win just by having more bitrate.

Some movie streams, maybe. "Gladiator" is a well-known example of half-bitrate DTS encoding.
Certainly not most Audio discs.
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post #12 of 44 Old 02-22-2007, 02:26 PM
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Quote:
Originally Posted by neil wilkes View Post

That's not right either. MLP only stores a downmix if you tell it to include one, otherwise it is a straight compaction process, complete with verification to ensure the output is bit-for-bit identical to the input.

Yes. My point was just that if you do specify the downmix, it is used to generate the 5.1 - it doesn't store 2-channel + 5.1 channels, or 5.1 channels with instructions to downmix, it stores downmix + 3.1 channels + downmix parameters. Saves a 2-channel player from having to have the power to decode 6 channels, and a 5.1-channel player uses the parameters to extract the original L+R from the downmix.
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post #13 of 44 Old 02-22-2007, 02:26 PM
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Quote:
Originally Posted by neil wilkes View Post

Because the additional information for the higher sample rates is carried not in the core, but in the extensions.

But that is interpolated 96/24, which can sound inferior to actual 96/24 audio. The poster I was replying to didn't "understand how come this format has been almost ignored by many people in favor of either MLP Lossless on DVD-Audio or DSD on SACD". One of the reasons is that DTS 96/24 isn't 96/24, at least to the extent that MLP is.
Quote:


I proved this recently with several people all at once.

Warner Bros Home Video, 5.1 Enterainment music labels, Home Theater Mag, and Home Cinema Choice have all done blind listening comparisons between DD and DTS, all unable to find one codec superior to the other. Warners and 5.1 Ent stopped using DTS on their DVD and DVD-A titles (respectively) after their recording engineers did the comparisons. The only thing supporting any claims of superiority is of the anecdotal "it sounds better to me" variety. Nothing objective in all these years of both codecs being around. Not even from DTS.

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post #14 of 44 Old 02-22-2007, 02:31 PM
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Quote:
Originally Posted by sdurani View Post

But that is interpolated 96/24, which can sound inferior to actual 96/24 audio.

No, it's not just interpolated 96/24. Look, it's clear you don't understand the fairly basic mathematical principles involved. Read my post above which illustrates how an encoding scheme can recreate original 96/24 data by applying an extension to a 48/24 core. DTS HD MA is core+extension, but is totally lossless, and identical to the original 96/24.

And yes, DTS 96/24 can sound inferior to actual 96/24, just as normal DTS can sound inferior to actual 48/24 audio. But that's nothing to do with the fact it's interpolated, it's the fact it's lossy compression.
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post #15 of 44 Old 02-22-2007, 09:22 PM - Thread Starter
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I guess the thread has gotten a little bit off topic, but I was trying to actually debate about the amount of titles that are actually out there in any surround sound formats.

One thing I personally love about DTS 96/24 is that it has been in use for pop songs in HK and in a lot of big HK movies.

These are a couple I own in DTS 96/24. All of these were mixed in 24bit96khz at the mastering stage before encoding to dts96/24

Music




Movies


The Banquet



Isabella

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post #16 of 44 Old 02-23-2007, 12:50 AM
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Quote:
Originally Posted by KMO View Post

Yes. My point was just that if you do specify the downmix, it is used to generate the 5.1 - it doesn't store 2-channel + 5.1 channels, or 5.1 channels with instructions to downmix, it stores downmix + 3.1 channels + downmix parameters. Saves a 2-channel player from having to have the power to decode 6 channels, and a 5.1-channel player uses the parameters to extract the original L+R from the downmix.

Rubbish!
Pur-leeze! Name your source for this disinformation.
How do you think that an MLP encoder can verify a 5.1 output as "bit for bit identical to the input" if it is only storing 2 channels of information.
Never heard such rubbish in my life.
You have never encoded anything with MLP, have you - as if you had you would see for yourself that a straight 5.1 encode produces a file of x megabytes, but include a downmix & the filesize increases. As it stores the extra information
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post #17 of 44 Old 02-23-2007, 03:01 AM
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Sorry Neil, any white paper on Dolby TrueHD or MLP explains this.

The technique is that it stores:

Left Downmix
Right Downmix
Left Surround
Right Surround
Centre
LFE

plus the downmix parameters used to create the downmix.

Then, because the decoder knows the downmix parameters, it's a trivial mathematical exercise to subtract off the LS,RS, Centre and LFE components from the downmix channels to get the original left and right channels. There's then a tiny bit of extra flummery to recover any least significant bits lost due to rounding errors in that maths.

TrueHD 7.1 uses the same trick - it stores the 5.1 downmix, plus the left and right rear surrounds, and the downmix parameters.

This Dolby document explains it - see pages 3 and 4.

Also, see this original Meridian paper, section 7.

Now, none of this is visible to someone such as yourself whose understanding of MLP's internal workings doesn't need to go beyond dropping 6 WAV files into a dialogue box, so I'm curious as to why you're so vehement that it doesn't work like that. I'm inclined to take Dolby + Meridian's word over yours...

How much does the filesize increase with the downmix, in your experience? By a factor of around 33%? That's what actually storing the downmix separately would require. Whereas this sort of layered encoding would only bump it up a bit (because the downmix channels will be more complicated than the isolated left and rights, thus compress a bit less well, plus the need for the "lsb bypass" to recover the rounding errors). The Meridian paper illustrates the extra space required in figure 18 - they reckon about 1 extra bit per sample, so maybe an extra 0.1Mbit/s for 96kHz.
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post #18 of 44 Old 02-23-2007, 03:24 AM
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PS - does anyone see the irony in that while Neil is patiently trying to explain the concept of core+extensions to get 96/24 from 48/24, he then totally fails to understand exactly the same concept as applied to getting multichannel from downmixes...?
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post #19 of 44 Old 02-23-2007, 03:50 AM
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It seems to me it is actually saying something different.
Quote:
7.1 Performing mix-down in the lossless encoder
MLP provides an elegant and unique solution. The
encoder combines lossless matrixing with the use of two
substreams in such a way as to optimally encode both
the Lt/Rt downmix and the multichannel version.

From the Meridian paper.

This is saying it is encoding 2 substreams, and this implies not just the downmix is stored, but both the downmix as well as the multichannel - which is confirmed by
Quote:
Suitable use of the substreams also allows 2-
channel compatibility; a low-complexity decoder can
recover a stereo mix from a multichannel stream.

(Again from the Meridian Paper.)

This is certainly not stating that only the downmix is stored - that would be an absurdity.
It is saying that various inefficiencies are packed better (hence the alternative nomenclature of "Packed PCM" in some players) to reduce entropy & repeating information.
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post #20 of 44 Old 02-23-2007, 04:01 AM
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Quote:
This is certainly not stating that only the downmix is stored - that would be an absurdity.

I never said that at all - please re-read my posts. I said that the stored downmix was used to recreate the original version, rather than just being stored separately and only being used for 2-channel playback. In other words, it's a 2-channel core, plus a multichannel extension, which is how we got onto the subject in the first place.

Really, I think you're suffering from either reading comprehension difficulties, or you've got some rather ingrained fixed misunderstandings about how MLP works.

My statement is simply that a MLP stream with downmix stores 6 channels, corresponding to:

Left Downmix
Right Downmix
Left Surround
Right Surround
Centre
LFE

Maybe there's some slight variance in the form of the extra 4, but it's 6 channels. Both documents explicitly state that.

Are you truly insisting that it actually stores 8 channels?

Left Downmix
Right Downmix
Left Front
Right Front
Left Surround
Right Surround
Centre
LFE

And that a 5.1 channel player ignores the downmix? If so, please go back and read the papers again.

Neither of the quotes you provide contradict me. The first states that it "encodes both the downmix and 5.1 channel version". Indeed it does - but so would storing the 5.1 channel version and downmix parameters. That statement says nothing about how it is actually stored. If you really think that it stores a separate downmix, then does the MLP encoder offer you a separate file input for the downmix? No it doesn't - it just lets you adjust the downmix parameters. Because that is the only information it is capable of storing. A 5.1 version plus downmix parameters.

But the format it stores it in is downmix + parameters + extension. That means that a 2-channel player doesn't have to decode all 6 channels, just the 2 downmix ones. Just like a 48kHz DTS decoder just decodes the core, not the full 96kHz stream.
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post #21 of 44 Old 02-23-2007, 04:05 AM
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Your use of the first quote irritates me. It looks as if you're trying to avoid the text that actually explicitly explains what it means. The next paragraphs explains in detail what it means. I'll repost it here for others' benefit. Bold is mine.
Quote:
MLP provides an elegant and unique solution. The encoder combines lossless matrixing with the use of two substreams in such a way as to optimally encode both the Lt/Rt downmix and the multichannel version. This method is shown in Figure 17.

Downmix instructions are used to determine some coefficients for the lossless matrices. The matrices then perform a rotation such that the two channels on substream 0 decode to the desired stereo mix and combine with substream 1 to provide full multichannel. Because the 2-channel downmix is a linear combination of the multichannel mix, then strictly, no new information has been added. In the example shown in Figure 17 there are still only six independent channels in the encoded stream.

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post #22 of 44 Old 02-23-2007, 04:19 AM
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Hmm, perhaps you don't understand what "lossless matrixing" means. It means changing the co-ordinate system to express a multi-dimensional quantity in a more convenient way. Any n-dimensional vector can be represented using any n axes, as long as they're independent.

So, for example, 2-channel stereo can be stored either as

1) "Left" and "Right"; or
2) "Left+Right" and "Left-Right"

The two are equivalent, and can be losslessly converted between, but the second form has the advantage that mono playback can be achieved with only the first channel. Also, the second channel will often be simpler to encode - MP3 etc often use this form ("joint stereo"). As does (did?) lots of general sound production in TV etc, I understand.

Consider also television. You could use:

1) Red, Green, Blue; or
2) Luma(R+G+B), Red Chroma(R-Luma), Blue Chroma(B-Luma)

All modern video uses the latter; monochrome playback only requires 1 channel, and luma and chroma can be compressed very differently because of the way the eye responds to them. It then gets losslessly transformed back to RGB for the display.

This MLP downmix system is exactly analogous. 6 channels of information can be stored as:

1) L, R, C, LFE, LS, RS; or
2) aL+bC+cLS+dRS+eLFE, fR+gC+hLS+iRS+jLFE, C, LFE, LS, RS

The latter 6-channel form has the handy advantage that the first two channels are a ready-made stereo downmix, with parameters a to j defined by the mixer. But just like the other cases, you can transform back to the original co-ordinate system.

In theory, the maths to reconstruct the original left and right is as simple as:

L=(Lt-bC-cLS-dRS-eLFE)/a
R=(Rt-gC-hLS-iRS-jLFE)/f

It's only rounding errors you have to worry about.

Actually, I've just realised that as the right channel can be included in the left downmix, and vice versa, the maths is more complicated - you've got to solve a pair of simultaneous equations. Still, simple enough though, but I'm not going to attempt to write it down here.
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post #23 of 44 Old 02-23-2007, 05:46 AM
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Okay, here are the equations. So I was bored.

If

Lt = aL+bR+cC+dLFE+eLS+fRS
Rt = gL+hR+iC+jLFE+kLS+lRS

then

L = [hLt-bRt+(bi-hc)C+(bj-hd)LFE+(bk-he)LS+(bl-hf)RS]/(ah-bg)
R = [-gLt+aRt+(cg-ai)C+(dg-aj)LFE+(eg-ak)LS+(fg-al)RS]/(ah-bg)

As should be clear, if the left channel isn't in the right downmix, or vice versa, then b and g are 0, and the equations reduce to those in the post above.

Of course, the trick is to construct all those co-efficients and perform the calculation in fixed point and with specified rounding. The encoder has to know what rounding errors the decoder will get, and pass through extra least-significant-bit info to compensate.

This is where the Dolby paper gets interesting, because then discusses similar extension techniques for the lossy codec Dolby Digital Plus. That sort of matrixing scheme is fine in theory, and when you're using a lossless codec, but doesn't work when you're not actually reconstructing the original data losslessly. So for DD+, they give in and transmit:

Left Front
Right Front
Centre
LFE
Left Surround for 5.1
Right Surround for 5.1
Left Surround for 7.1
Right Surround for 7.1
Left Back Surround
Right Back Surround

So a full 9.1 channels of info. But they can then presumably rely on the compressor spotting inter-channel similarities so it compresses quite well.
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post #24 of 44 Old 02-23-2007, 05:53 AM
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Hmm, I am suddenly curious though. What happens if you set the Lf and Rf mix parameters to the same for both Lt and Rt in the encoder (effectively making the downmix include a mono collapse of the fronts)? Or indeed if you excluded Lf and Rf from the downmix altogether! That would render it undecodable (divide by zero in the equations). I just tried setting that it in my SurCode MLP demo, and it didn't immediately object. Presumably it would object at the point you actually started the encode, or as soon as it ran the verification.
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post #25 of 44 Old 06-01-2007, 11:46 AM
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If I may inject a diversion - I'm curious as to what information tends to be 'lost' in the DTS 96/24 core + extension playback. Or to put it a different way, just what is it that makes DTS 96/24 lossy compared to, say, DTS-HD Master Audio? Also, is lossy perceptual encoding applied to both the core and extension frequencies or just to the core?

As for DTS vs DD of the same source (and assuming level matching), to be definitive that requires a *double* blind test, with multiple trials (at least ~16 per subject); and running such tests using groups of people at once is usually a bad idea unless independent responses can be assured., otherwise people can and will influence each other's preferences.
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post #26 of 44 Old 06-03-2007, 07:34 AM
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I am not sophisticated enough to get into the minuet details of the various formats except to say when comparing the DD to DTS soundtracks on several Music DVD's, I think it depends on who is doing the mixing. That being said, I am extremely disappointed that my Peter Gabriel's "Play--the Videos" DTS 96/24 track doesn't play on my newer Denons. It ROCKED on my AVR 3803 and AVR 4802R, but sucks on my AVR 3805 and AVR 4806. Insofar as DVD-A is concerned, There is nothing cleaner sounding than REM's compilation "The Best of REM," imo.
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post #27 of 44 Old 06-03-2007, 05:51 PM
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I'm curious about the discussion in this thread relative to THIS thread.

"All men are frauds. The only difference between them is that some admit it. I myself deny it."
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post #28 of 44 Old 06-03-2007, 07:57 PM
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soon there will be nothing but mp3



All this noise about noise.
♪♫♪♫♪♫♪♫♪♫♪♫♪♫♪♫♪♫♪♫♪♫♪♫
Finding the acoustic sweet spot.
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post #29 of 44 Old 06-04-2007, 08:57 AM
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nonsense, with storage costs coming down so fast, soon, it will be mainly lossless files, with lossy files (at higher bitrates than 128 kbps) used exclusively for portable players.
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post #30 of 44 Old 06-05-2007, 05:59 AM
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Quote:
Originally Posted by krabapple View Post

nonsense, with storage costs coming down so fast, soon, it will be mainly lossless files, with lossy files (at higher bitrates than 128 kbps) used exclusively for portable players.


Isn't that WONDERFUL
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