Dolby Digital 2.0 vs. DPL 2.0 or "Dolby Surround"

Discussion in 'Apple TV and Home Theater' started by Icaras, Apr 26, 2009.

  1. Icaras macrumors 603

    Icaras

    Joined:
    Mar 18, 2008
    Location:
    California, United States
    #1
    I am trying to find out if there is any distinguishable difference between Dolby Digital 2.0 and Dolby Pro Logic in 2 channels, other than it being stereo.

    The reason why is that I have some TV shows on DVD that were originally encoded to play in Dolby Digital 2.0, and those same movies and TV shows that are stereo sources to begin with do not display the DD logo in the iTunes store, which to me means, just Dolby Pro Logic, matrixed in just your basic 2 channel stereo source.

    Maybe I'm just confusing the hell out of myself over nothing, but could anyone tell me if the DD 2.0 on the DVDs would actually be of a higher quality than the 2.0 material found on Apple's iTunes store? Thats what I'm really trying to find out.
     
  2. cleric macrumors 6502a

    cleric

    Joined:
    Jun 7, 2008
    Location:
    Minneapolis, MN
    #2
    Depends what the source is for the stereo encodes. I assume they are encoded in to aac which is a better compression algorithm than ac3, but the ac3 may have been sourced higher.
     
  3. eddyg macrumors 6502

    Joined:
    Sep 5, 2003
    Location:
    Christchurch, New Zealand
    #3
    Without knowing the bitrate you can't say which is better. AAC (which the dolby surround stream is using) at the same bitrate as AC3 (DD) will give better fidelity due to having better compression.

    Personally I think the following are comparable in quality:

    AC-3, rate=48000Hz, bitrate=224000 (2.0 ch)
    AAC, rate=48000Hz, bitrate=160000 (2.0 ch)

    Don't worry about stereo sources, but do choose for DD 5.1 sources over matrixed dolby surround sources, that is noticeable.

    Cheers, Ed.
     
  4. Icaras thread starter macrumors 603

    Icaras

    Joined:
    Mar 18, 2008
    Location:
    California, United States
    #4
    Yes, this I do know very well and clear. But thank you both for clearing up some of the differences between AAC vs. AC3.
     

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