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Getting DD 5.1 out of a vcr?

Discussion in 'Archived Threads 2001-2004' started by NathanP, Nov 3, 2001.

  1. NathanP

    NathanP Supporting Actor

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    I know you can't get Digital from analogue but here's a question.
    I've seen many THX certified VHS tapes that say they're Dolby Digital encoded..
    How can I get DD 5.1 then?
    I don't believe there are any VCR's with digital outs but I may be wrong.
    Thanks guys!
    Nathan
     
  2. Rob Gillespie

    Rob Gillespie Producer

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    In short - you can't. Any VHS tape that says it has a Dolby Digital track is incorrectly labelled. The most you'll get out of VHS is analogue HiFi Stereo.
     
  3. Brett DiMichele

    Brett DiMichele Producer

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  4. Justin Lane

    Justin Lane Cinematographer

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    Brett, why do you say it is a crock that Toy Story 2 on VHS is THX certified. There are many THX certified VHS tapes on the market. THX has nothing to do with the format being used, but instead the mastering process to some degree.
    Nathan, what you could be seeing is the ending credits or the back of the box where it shows what the sound formats that were presented theatrically for the film. If you watch the end of the credits of some films you might even think it has a DTS or SDDS track. It is just part of the credits, nothing more.
    J
     
  5. Chris PC

    Chris PC Producer

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    I do consider myself an "audiophile" in that I really do appreciate and strive for better and better sound, but VHS hi-fi is really decent quality sound considering the format. I know its only DPL, but thats where DPL-II comes into play [​IMG]
     
  6. Seth T

    Seth T Stunt Coordinator

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    I'm inclined to agree with Justin. I've seen a lot of "THX Digitally (re)Mastered" VHS tapes. Maybe you're confusing that with Dolby Digital?
    -Seth
    ------------------
    My Home Theatre
     
  7. Andrew Pratt

    Andrew Pratt Producer

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    Actually a VHS tape can be Dobly Digital. DD isn't strickly a 5.1 format it comes in many flavors incl. 2 channels.
    ------------------
    http://www.mts.net/~glendap/
     
  8. Rob Gillespie

    Rob Gillespie Producer

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    Nope, sorry. VHS cannot hold Dolby Digital. DD, regardless of the number of active channels is a digital audio format. The 2-channel audio on VHS is analogue HiFi Stereo.
     
  9. Glenn Overholt

    Glenn Overholt Producer

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    Rob, but if a new movie is made using DD for the master, the original would be DD encoded. Of course if they transfered that to a VHS tape, it would come out analogue (hi-fi stereo), but have a DD origin, correct? Sorry to nitpick, but I think this is the correct translation.
    The fact that the DD symbol on the back of the VHS tape is true, but it is probably there just because its in the closing credits of the movie. (In other words, they didn't have a clue when they put that on the box).
    Glenn
     
  10. Chris PC

    Chris PC Producer

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    This isn't like the old ADD, DDD and AAD of the old compact discs and how they are recorded, produced, mastered/engineered and finally recorded on disc. DD is commonly understood to mean that you the user, in your home, is playing back a DIGITAL signal being processed by the CPU in the "DECODER" in your playback equipment (receiver/ pre-pro etc) which then goes to each of your separate surround, front, center and subwoofer speakers of the DD format in a much more discrete fashion than with matrix or pro logic surround. That is not happening in a VHS vcr. VHS is totally analog. If Video tapes do say DD, I don't care how they were made, that's just a silly marketing thing to put it on the tape because it can be easily misunderstood as being the same as the DD we are all familiar with today, the real Digital versions found on LD's and DVD's. Whatever comes out your speakers from a VHS tape source is either pro-logic or matrixed stereo or surround sound. There is no digital audio on video tapes. Funny, but its not impossible, surely they could record digital audio on a video tape if they wanted to. Its just that in order to playback, you'd need a specific VCR to do that and then the tapes would only play on those vcr's. Shiney discs have taken over. Digital audio and video for that matter would have created a compatibility issue that would made the new format of videotape less marketable maybe?
    [Edited last by Chris PC on November 03, 2001 at 07:46 PM]
     
  11. BruceD

    BruceD Screenwriter

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    If you pay close attention to the markings, I believe you will read Dolby Stereo or Dolby Surround on most of the VHS tapes. This was Dolby's original trademarks on stereo movie material before the introduction of digital into the home.
    This would be similiar to DD2.0 in the digital domain. Both can take advantage of today's DPL II to get a very respectable 5.1 soundstage, even from VHS.
    Bruce
    [Edited last by BruceD on November 03, 2001 at 10:31 PM]
    [Edited last by BruceD on November 03, 2001 at 10:32 PM]
    [Edited last by BruceD on November 03, 2001 at 10:34 PM]
     
  12. Adam Barratt

    Adam Barratt Cinematographer

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    Rob is 100% correct. You cannot get Dolby Digital from VHS.
    Adam
    [Edited last by Adam Barratt on November 04, 2001 at 03:01 AM]
     
  13. Jeff

    Jeff Supporting Actor

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    THX is nothing more than a stamp of approval for achieving the best audio and video quality.
    Why it's associated with VHS is beyond me.
    Jeff
     
  14. Rob Gillespie

    Rob Gillespie Producer

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    OK, the best way to think of Dolby Digital (or DTS for that matter) is as a carrier format. Lots of different channel configurations and uses, but really just comes down to how an audio signal is compressed and stored on a digital medium.
    quote: Rob, but if a new movie is made using DD for the master, the original would be DD encoded. Of course if they transfered that to a VHS tape, it would come out analogue (hi-fi stereo), but have a DD origin, correct? Sorry to nitpick, but I think this is the correct translation.[/quote]
    The thing is Glenn, movies aren't made in DD, DTS or SDDS. The final orignal master soundtrack will most likely be in an uncompressed format such as PCM. The Dolby, DTS and SDDS (compressed theatrical or home formats) are then derived from that original.
    The actual format of a soundtrack will be stereo, mono, 5.1 discrete, 5.1EX/ES, 6.1 ES. A stereo soundtrack may be 'Dolby Surround' which means it has centre and rear channel information phase-plexed into the two-channel signal.
    Dolby, DTS and SDDS are just carriers.
    [Edited last by Rob Gillespie on November 04, 2001 at 04:15 AM]
     
  15. Marty Neudel

    Marty Neudel Stunt Coordinator

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    >if a new movie is made using DD for the master, the original would be DD encoded<
    Glenn,
    movies are made using uncompressed digital tracks, then mixed through DD, DTS, and SDDS encoders. If a movie were made using DD then the resulting tape would have all the artifacts of digital encoding, DD compression, and FM HiFi analog sound. I suspect it would not be the cleanest sounding VHS tape in your collection. [​IMG]
    Marty
    [Edited last by Marty Neudel on November 04, 2001 at 06:14 AM]
     
  16. Wes

    Wes Screenwriter

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    If you install a flux capacitor on the Right and Left output jacks and cross that with 22gigawatts of power I think that will extract the DD! [​IMG]
    Wes
     
  17. Chris PC

    Chris PC Producer

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    Ooooo. Wes solves world hunger and extracts DD from VHS tape in one quick soldering job [​IMG] Cool. But Wes, I think I could almost buy a small manufacturing company to make myself personal digital VHS copies with DD before I'd have a 22 giggawatt source of power [​IMG]
    Really though, now that I have a new VCR and new speakers, I'm totally impressed with VHS tape audio. It really is Hi-Fi. I can't wait to get my receiver back to try DPL-II on rentals and other VHS material. Should be pretty darn cool to say the least. I think Analog VHS tape Hi-Fi was one of the better audio things to come out of the 80's. Cassette tape was a disappointment for me during the 80's, so when Hi-Fi VHS came out, I was impressed and I still am today. Stereo or surround, it sounds nice and clean and has good dynamics. Hell, we'll all be using DVD's more and more in the years to come, but at least when we rent video tapes or "non-video/audio-phile" friends rent or bring over their own videos we aren't stuck with crappy sound.
    [Edited last by Chris PC on November 04, 2001 at 08:11 PM]
     
  18. Luke_Y

    Luke_Y Second Unit

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    Now Wes, Don't go misleading people...
    It's 21.1 gigawatts [​IMG]
    ------------------
    Luke
     
  19. Sean Conklin

    Sean Conklin Screenwriter

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    quote: If you install a flux capacitor on the Right and Left output jacks and cross that with 22gigawatts of power I think that will extract the DD! [/quote]
    Wes, contrary to popular belief and the great work of Dr. Emmett Brown, you can extract the DD with only 1.21 gigawatts. Yes, the gigawatt power value of 1.21 is the scientific standard of all things powered by a "gigawatt".
    For example in a time travel vehicle if you were to boost the flux capacitor to 1.22 gigawatts you would in effect overpower the flux capacitor, cause an explosion, and would not be able to time travel! If you were to under power the flux Capacitor with only 1.20 gigawatts or less, you would create an incomplete time cross and would wreak havoc on the space time continuum, including but not limited to partial body parts arriving at the intended destination.
    The same goes for DD extraction from a VHS tape vehicle, If you were to use only 1.20 GW, you would get the equivalent of DPL 3.0, OTOH, if you were to use 1.22 gigawatts you can extract dts, but only a dts 4.1 track. If you use the universal scientific standard of 1.21 gigawatts and a THX approved Flux Capacitor you can extract exactly DD 5.1!
    So Wes your suggestion of 22 gigawatts would be disastrous, not to mention that 22 gigawatts is not obtainable with todays technology! [​IMG]
    ------------------
    Sean
    "I was thinking of the immortal words of Socrates who said.......I drank what?"
    [Edited last by Sean Conklin on November 04, 2001 at 09:14 PM]
     
  20. Jesse Skeen

    Jesse Skeen Producer

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    I'm working on putting a Dolby Digital signal on CED videodiscs, decodable with an RF demodulator [​IMG]
     

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