5.1 and S/PDIF

Discussion in 'Hardware Discussion & Support' started by dj_stick, Jul 29, 2004.

  1. dj_stick

    dj_stick Apple Fanboy?

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    A common misconception is that S/PDIF digital audio signals will provide a 5.1 channel sound.

    This is not true.

    S/PDIF is a 2 channel stereo format, regardless of the medium (optical or coaxial)

    The exception to the rule is when a form of compression is used.

    Dolby Digital (AC-3) compresses 6 channel signal into the 2 channel format used by S/PDIF, and can then be read by a decoder.

    No soundcard apart from the nForce 2 Soundstorm chip so far can encode AC-3. Therefore if you do not have one of these motherboards, the only way to get 5.1 channel sound over S/PDIF is to play a source that is already encoded in the format, such as a DVD video.
     
  2. Judas

    Judas Obvious Closet Brony Pony

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    excellent information..... i've never really used s/pdif... is that the optical port?
     
  3. dj_stick

    dj_stick Apple Fanboy?

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    yes it can be in the opticle medium aswell as coaxial
     
  4. DavoNogo

    DavoNogo New Member

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    the latest version of AC3Filter can encode PCM, AC3, DTS, MPEG Audio and PES (a DVD format) on the fly
     
  5. exorcism

    exorcism New Member

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    Is there anyway to use this technique for playing games in surround?
     
  6. dj_stick

    dj_stick Apple Fanboy?

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    the program should automatically do that… but will increase CPU load - possibly reducing performance in your game
     
  7. exorcism

    exorcism New Member

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    Isn't AC3Filter an acm codec/filter or something? As in, use it in windows media player? I don't see how I could use it for a game.
     
  8. dj_stick

    dj_stick Apple Fanboy?

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    afaik AC-3 filter attaches itself to the directsound outputs before it reaches the soundcard, and should work for any directsound application
     
  9. justarandomuser

    justarandomuser New Member

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    This doesn't work for games.

    Sadly
     
  10. Lowfat

    Lowfat Xtreme

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    Thats why i love my Soundstorm :)
     
  11. classic_leon

    classic_leon New Member

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    Yeah,excellent information! I think S/PDIF is now the best solution to 192KHz/24Bit DVD-AUDIO for PC.
     
  12. dj_stick

    dj_stick Apple Fanboy?

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    the S/PDIF medium can't support anything more than 24/96 afaik
     
  13. classic_leon

    classic_leon New Member

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    If I play 192/24 DVD-AUDIO via S/PDIF to stereo speakers of A2 platinum drive, what will happen? will the speakers hiss? Thanks.
     
  14. dj_stick

    dj_stick Apple Fanboy?

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    no - it will be limited to 24/96 - read the specs for your audigy 2, i'm pretty sure it only says s/pdif output is 24/96 at maximum
     
  15. classic_leon

    classic_leon New Member

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    I got it. Thank you!
    Actually I haven't tred it before. I will go n try to play this using S/PDIF.
     
  16. bollwerk

    bollwerk New Member

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    So currently, the only way to play games in 5.1 and send the output digitally to a home stereo is with the now-discontinued nVidia SoundStorm?

    Why doesn't Soundblaster just license an AC-3 encoder for their S/PDIF output?
     
  17. dj_stick

    dj_stick Apple Fanboy?

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    the hardware has to be powerful enough to support it, and dolby has to licence the technology
     
  18. siriuz

    siriuz New Member

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  19. dj_stick

    dj_stick Apple Fanboy?

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    yes ONLY if the original input signal/source file is 5.1, as this is its AC-3 passthrough mode

    EDIT: the digital out jack on the audigy cards uses a 4 pole jack that gives 3 seperate stereo SPDIF connections plus a ground wire, for a total of 6 channels (5.1)
     
  20. siriuz

    siriuz New Member

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    ah.. ok.. thanks for the quick reply :)

    so a special cable is needed ?
     

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