DTS ES Discrete versus Dolby EX?

Discussion in 'Archived Threads 2001-2004' started by RichardMA, May 24, 2002.

  1. RichardMA

    RichardMA Second Unit

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    Knowing how few DTS DVDs exist relative to the total
    number of DVD discs out there, I'm wondering what prevents
    Dolby from introducing a discrete 6.1 channel DD format?
    Knowing what the move from say an older DD 5.1 only decoder
    to a new all-format 6.1/7.1 decoder costs, I can't help
    but wonder exactly how many movies I'll want to see out
    of the small number of DTS encoded ones that exist.
    Put it this way; If I watch 100 movies this year, most
    will be in DD, so the "cost per movie" is relatively low
    when you factor in the decoder cost. But the "cost" to
    listen to DTS-encoded movies is going to be high when you
    factor in the decoder cost. If you only watch a couple
    dozen DTS-encoded movies a year, then they technically
    cost far more (each) than listening to DD movies.
     
  2. Adam Barratt

    Adam Barratt Cinematographer

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    Dolby Digital in its current form is incapable of reproducing more than six discrete channels. Any new system that included additional channels would not be compatible with existing Dolby Digital decoders, which would make it an impractical proposition (this is a trick that DTS, which is more flexible, was capable of pulling off).

    'Splicing' a conventional 5.1 and a 2.0 soundtrack might be possible, but would require a new decoder and DVD player configuration. The 5.1 soundtrack would remain compatible with existing decoders (as would the 2.0, but would be unusable on its own), while those with newer decoders would get eight fully discrete channels (back-surround and height?). This would be a complicated operation, however.

    Dolby have stated many times in the past that they have no plans to introduce a new 6.1 audio format, but who knows what the future will hold.

    Adam
     
  3. John Garcia

    John Garcia Executive Producer

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    I don't understand the question or the point? There are VERY few discs that are DTS ONLY these days (I think most or all of them are out of print). All of the discs that I have that have ES tracks also have standard DD tracks, so the cost vs decoder is basically irrelevant. If the decoder does ES, the likelihood it won't do EX is extremely low also.
     
  4. ThomasL

    ThomasL Supporting Actor

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    My guess is that the current bandwidth limitations in the DD protocol limit it's ability to carry another full discrete channel (6.1). I have not looked at technical specs for the protocol but I suspect that somewhere is defined how fast and how many bits can fly from the reader to the decoder. Just like there are bandwidth limitations for low level computer network protocols (e.g. 100 Mbit/sec ethernet).

    cheers,


    --tom
     
  5. RichardMA

    RichardMA Second Unit

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    Very few discs have DTS Discrete (which is not the same
    as DTS ES Matrixed or Dolby Digital Matrixed). In fact,
    flags or not, you can basically use the 6.1 channel matrix
    docoders on all 5.1 sources and achieve varying results.
    You can even force 2.0 channel stereo tracks though a
    DTS or DD matrix decoder and you might come up with something that is listenable. But you can't do that with
    DTS Discrete decoding. Which I guess is why we won't see
    any stand alone DTS-Discrete decoders.
     
  6. Roger Dressler

    Roger Dressler Stunt Coordinator

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    Lanching an extended version of Dolby Digital is technically possible just as it was for DTS. In both cases, it needs a new decoder to detect and decode the new channel, while existing decoders just ignore it. But the coder is just one step in the chain, so without content to drive it, there'd be no point in adding more delivery channels. This is borne out by the DTS ES discrete situation, which requires expensive remixes to be made because 6.1 discrete is not used for film soundtracks.
     
  7. Adam Barratt

    Adam Barratt Cinematographer

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    Interesting. How would the additional channel be added? As I understand it, DTS used its larger size and padding data to squeeze in an extra channel. I was aware of an option to increase Dolby Digital's sampling rate to 96kHz using extension data, but not to add extra channels.

    Utilising 'extra' information within the conventional data, as with DTS, would seem unlikely as I doubt there is any with Dolby Digital (at least not without also reducing the resolution or frequency response of the six core channels). Would an additional external datastream be needed, as with DTS 24/96?

    Any further elaboration, even if purely academic, would be appreciated.

    Adam
     
  8. Dan Hitchman

    Dan Hitchman Cinematographer

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    Ah, but when the time and effort is made to create a 24 bit, 6.1 discrete master for DTS-ES Discrete 6.1 encoding as in the case of The Haunting and Gladiator and Chicken Run, the results can be spectacular!

    Too bad more post production audio mixing facilities don't master to 6.1 (discrete mono back channel) or even 7.1 (discrete stereo back channels) and then down mix for the 5.1 EX/ES theatrical version. At least that way they're more prepared for what the future may hold in store, and there is no need to spend further money on remixes.

    Discrete 5.1 as a speaker array standard, as some audiophile sound engineers have stated, was the lazy way out.

    Dan
     
  9. Earl Simpson

    Earl Simpson Supporting Actor

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    """"I'm wondering what prevents
    Dolby from introducing a discrete 6.1 channel DD format"""

    I am confused as usual! Oh well!!! I thought ddes discrete was 6.1 discrete and ddex discrete was 6.1 discrete????????????????????????????????????????
     
  10. Jeff Kohn

    Jeff Kohn Supporting Actor

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  11. Wes

    Wes Screenwriter

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    In the mid 80's we got Dolby surround, Prologic in late 80's. DD in the mid 90's and DTS in the late 90's. EX/ES and Prologic II in the early 2000's as well as DTS 6.1.
    Do you really think DTS ES 6.1 will be the stopping point for sound tracks? We have had to upgrade our equipment to take advantage of all these other formats why would should it be any different now if Dolby said "Hey we now have 10.2"!
    Things seem to be changing quicker now with newer technology.

    Wes
     
  12. Craig_Kg

    Craig_Kg Supporting Actor

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    OK, can someone tell me what the discrete center rear does?

    With a matrixed center rear, isn't the common signal for the rears extracted and sent to the rear center instead (like a DPL center)? If that is the case then the only advantage I can see of a discrete rear (especially if it is backwards compatible with 5.1 systems) is that the center rear information is not totally drawn out from the normal rears so it is, err... less discrete.
     
  13. ThomasL

    ThomasL Supporting Actor

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    Craig, in DD-EX and DTS-ES Matrix, the sound engineer creates a separate rear channel which is then "matrixed" within the surround channels' information. When decoded, it is extracted and played out the rear speaker(s). In DTS-ES Discrete, there is actually a 6th channel mixed and encoded completely separate from the other 5.

    cheers,


    --tom
     
  14. Craig_Kg

    Craig_Kg Supporting Actor

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    Yes but if the "matrixed" information is extracted from the rears surrounds, for the rear center, then how different is the effect of the "discrete" signal apart from allowing overlap with the rear surrounds (which would make it less discrete in effect)?
     
  15. ThomasL

    ThomasL Supporting Actor

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    Craig, I'm not sure what you're asking but I would assume that things that should sound like they are behind you will be matrixed into the rears for that 6th channel. A good example is the current Star Wars movie in the theater. There were a few scenes with ship fly overs where the sound of their engines started in the back channel and moved to the front as the ship flew directly overhead - or that was the intended feeling. If your point is that the rear back channel is essentially just more surround sound that could come out of the 2 surround speakers, then yes, it won't add to the affect and may lessen it. This is what may happen if you listen to a 5.1 mixed movie with the 6.1 processing on. Some movies may sound better, others may not sound as good since the rear channel is extracting too much away from the surrounds - where the sounds were intended to be played.

    cheers,


    --tom
     
  16. Dan Hitchman

    Dan Hitchman Cinematographer

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    Craig,

    The rear back "matrixed" info on the left and right surrounds in a DTS-ES Discrete 6.1 track decoded on a DTS-ES Discrete decoder are de-matrixed and filtered out (disgarded), then the discrete, sixth channel (which is in a separate flagged extension packet) is extracted and sent to the appropriate back channel.

    However it is done to have both a 6.1 discrete track and a 5.1 ES matrix track (for backwards compatibility), the results are quite effective and much more precise than DD EX or straight DTS ES matrix (which is not surprising). To these ears I hear no cross-talk in the various surround speakers when the DTS-ES Discrete 6.1 track is fully decoded on my Outlaw Model 950 pre-amp.

    I think Dolby Labs was a day late and a dollar short with Dolby EX when they decided to start adding matrixed channels back into the fray. Full range, discrete channels are the ONLY way to go.

    Dan
     
  17. Wes

    Wes Screenwriter

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    Craig, I understand what you are asking! I do not have
    DTS ES 6.1 so I have not had a chance to test it. And I know most people (here included) do not under stand how EX/ES works. There is no magical mystical EX cannel recorded in a so called matrixed EX/ES system (there was never any front center channel recorded into a stereo or Dolby Surround source, but a center channel is created by moving Inphase Mono info into the Front Center channel). All that goes on is if the sound mixer/producer wants something to start out in the back of the room (EX/ES channel) the sound will be recorded Inphase Mono in the surround channels! Then as the sound moves into the theater it will slowly be separated into stereo with retaining the same volume amount in each surround L/R channel. Then as the sound moves to the front it will be faded out of the EX/ES and into the front L/R channels and then will again be faded into the center channel as the sound goes away from the audience into the screen.
    Now I do not know how this same sound moves through DTS ES 6.1. It seems to me that if done correctly when 6.1 is selected on the processor that the decoder will have to remove the "Inphase Mono" info that is there in the surround Left and Right channels. Sense the Mono rear surround is now recorded in its own channel this mono info must be tossed out and not used???????
    If the Mono info is not removed from the L/R Surrounds all 3 surround channels would be firing at the same time same vol. when the above mentioned sound ran through the theater, which would NOT give a good EX sound experience.

    Could someone with 6.1 capabilities take the time to find a good "front to back or back to front" scene in a movie that is in 6.1 and compare the L/R surround channels to the 5.1 EX/ES in relation to the 6.1 track. I would be interested to know how the surrounds differ!

    Wes
     
  18. Craig_Kg

    Craig_Kg Supporting Actor

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    OK, so discrete basically allows more control over the balance of the rear soundstage instead of collapsing all common rear information to the rear center(s). I can see this having a big benefit when something "pans" across the rears.

    Thanks for the info everybody.
     
  19. ThomasL

    ThomasL Supporting Actor

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    Craig, Dan is right. In order to maintain "backwards compatability" a DTS-ES Discrete soundtrack also contains the matrixed version in the surrounds. When played in DTS-ES Discrete processing mode, this is removed. I've only listened to Gladiator in this mode but I can say, there is a noticeable positive difference. Discrete channels are definitely the way to go and I suspect in the future, we'll see a new Dolby Labs protocol that allows for 7.1 discrete channels (two rears each with their own separate channel). Then they'll have a reason for everyone to upgrade their dvd player and their receiver/processor [​IMG]
    cheers,
    --tom
     

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