Dolby Pro Logic and Pro Logic II

Discussion in 'Archived Threads 2001-2004' started by AndrewDavid, Jan 14, 2003.

  1. AndrewDavid

    AndrewDavid Auditioning

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    I have a receiver that decodes Dolby 5.1, dts, and Pro Logic only. So what happens when it receives a Pro Logic II signal (in my situation, from GameCube games)? I am still getting "surround" sound out of my rear speakers, so I am assuming it is just being decoded in normal Dolby Pro Logic using "one" rear channel (the left rear and right rear make the same sound), not "separate" left rear and right rear signals. Is this correct?

    Thanks!
     
  2. Alf S

    Alf S Cinematographer

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    You are correct...if it's PLII and your decoder doesn't offer that, you'll get PL1 instead.

    Alfer
     
  3. Rick_Brown

    Rick_Brown Second Unit

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    My understanding was that there is no Pro-Logic II "encoding" method; it is a "decoding" method only. I know that there is no such thing as a PL2-encoded video. Are you sure that your Gamecube has PL2-encoded info?
     
  4. AaronJB

    AaronJB Second Unit

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    Some Gamecube and Playstation 2 (for example, "Treasure Planet" on PS2) are labeled as having "Pro Logic II" soundtracks.
     
  5. MancusoB

    MancusoB Agent

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    Yep.

    Wipeout Fusion for the PS2 even includes a "Dolby ProLogic II" splash screen.
     
  6. Lee Carbray

    Lee Carbray Second Unit

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    Rick is right. PL and PL2 are a processing applied to a stereo signal.
    see more here. dolby labs
     
  7. Jeff Holton

    Jeff Holton Stunt Coordinator

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    Here is a quote from the Dolby websight... is sounds like you can encode a signal differently to take advantage of PL II.

    ************************************************** ********
    While conventional surround programming is fully compatible with Dolby Surround Pro Logic II decoders, soundtracks will be able to be encoded specifically to take full advantage of Pro Logic II playback, including separate left and right surround channels.
    ************************************************** ********
     
  8. ChrisWiggles

    ChrisWiggles Producer

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    That is true, any PL1 or PLII decoder can be applied to any stereo sourcem however, some mixes, particularly movies, and now games too, and also some music, are mixed with this in mind, so that the affect of PL decoding is taken into account. If something is "encoded" PLII, its isn't being encoded, but mixed in a way such that a sound that is supposed to be in the rear left throuhg PLII shows up there. So, really, compatibility is never an issue.
     
  9. KevinDLV

    KevinDLV Auditioning

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    Supposedly PLII basically updates their original PL standard from the 80s to the new millenium, which not only enhances old Dolby Surround and Pro Logic soundtracks, but games can be specifically decoded to play PLII, which has full-bandwidth left and right matrixed surround channels.

    I say, not bad coming out of two analog inputs, and this is much more practical than using the Optical on the PS2 and xbox.
     
  10. Rick_Brown

    Rick_Brown Second Unit

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    ChrisWiggles, I think your explanation is spot-on. On observation, the Gamcube and Playstation makers are using good marketing techniques - consumers see that their receivers have PL-II, so the game manuafacturers play up to it. Nothing wrong with that.
     
  11. Ted Lee

    Ted Lee Lead Actor

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  12. KevinDLV

    KevinDLV Auditioning

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    Brown, Wiggles:

    I thought that the GameCube had a sort of real-time PLII encoder, similar to the 5.1 on xbox, that can place sounds in the areas of the game they should be during real time. Since PLII is an update of PL that it has full bandwidth left and right surrounds (separate and not limited bandwidth, unlike the single mono limited bandwidth channel of PLI) and I don't think it is a marketing gimmick because not all games have support PLII, I remember a thread showing which GC games supported 480p and PLII, and which xbox games supported widescreen/480p/DD 5.1.

    I'll try to find that link.
     
  13. ChrisWiggles

    ChrisWiggles Producer

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    Now, older game systems had software that placed sounds appripriately left/right, and now it's a little more complicated, to do the phase shifting, and whatnot to get PLII to come out right when processed, but it is essentially the same thing. It's still placing them on the two stereo tracks, just in a little more complicated way. Using the word "encoded" is bound to confuse people, so be careful.
     
  14. MichaelMOS

    MichaelMOS Agent

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  15. KevinDLV

    KevinDLV Auditioning

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    Maybe not then. I think someone with a PLII reciever and a GC try it out though and see how it sounds. What I want to know is if the left and right surround channels play independent music and effects from each other, because that would mean that DLII is supported and utilized, unlike the PLI single surround mono channel.
     
  16. ChrisWiggles

    ChrisWiggles Producer

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    GC "supports" PLII. I've heard it on one of the rogue squadron games, they have a little tie-fighter fly-around test of PLII, and it goes all around in a circle.
     
  17. AndrewDavid

    AndrewDavid Auditioning

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    Not to beat a dead horse with all the discussion of Pro Logic and Pro Logic II around here lately, but...
    I usually leave my receiver on "auto-detect" which works pretty well for DVDs (switching from Stereo or PL during menus to dts or DD5.1 during the actual movie), but not so hot with my game systems. I always have to manually switch to "surround" to get Pro Logic to kick in while using the GameCube (Metroid Prime, which definitely supports PLII, sounds awesome). It seems that my receiver always interprets this signal as "stereo" only. Is this typical? Are we meant to physically tell our receivers to start decoding in PL or PLII?
    Any help would be greatly appreciated... then I'll shut up about Pro Logic for a while and go back to enjoying all that dts has to offer! [​IMG]
     
  18. Rick_Brown

    Rick_Brown Second Unit

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    I dopn't think that the fact that a game has planes flying around in a circle in PL-II means that PL-II is necessarily supported. After all, I hear discrete-sounding effects in the rear channels with old PL-I movies - that's what PL-II is supposed to do, right?
     
  19. KevinDLV

    KevinDLV Auditioning

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    PLII is supposed to be discretely left and right channels, and also full bandwidth which means they don't chop off higher and lower octaves like older PLI. And supposedly old PLI and new PLII stuff sound better because it's a better algorithm.
     
  20. ChrisWiggles

    ChrisWiggles Producer

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    I think you mean left and right surrounds. And the surrounds are not discrete at all. The left total/right total (stereo essentially) is as discrete as any other stereo source. When you apply PLII processing, it CREATES a center, and two surrounds. Yes PLII has different left and right surround information, and it is not bandwidth limited. PLI had mono surrounds, was generally worse with sound leakage between channels, and was bandwidth limited in the surrounds.
     

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