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Surround decoder

  1. Nov 16, 2004 #1
    Hello science fellows!
    I have a problem.I would like to do surround decoder in Matlab.Does enybody knows how to do it?How should I get started?What kind of test could I apply:simple sine signal in .m file or some .wav file?
    Many thanks for help
     
  2. jcsd
  3. Nov 19, 2004 #2
    Sorry, but this somehow relate to surround sound?. I thought that was just your basic sterio with front, back, left, right speakers.
     
  4. Nov 19, 2004 #3

    Cliff_J

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    Surround sound comes in many flavors today but think back to the days of "Dolby Pro-Logic" and how it worked. Movie tracks were recorded on the filmstrip in 4 channels intended for left, center, right speakers behind the perforated screen and one surround channel to be played on the speaker array on the walls/ceiling/rear of the theater.

    Since the job of the center was primarily for dialog and to assist in action that moves offscreen across to the other offscreen it was mixed onto the left and right as a mono signal in-phase. The surround was mixed as a mono signal out-of-phase on both left and right channels. The left and right were untouched aside from having an additional signal added to them.

    So the decoder's job was to seperate out mono in-phase and out-of-phase signals and send them to the appropriate speaker and then subtract this from the L/R and send those signals to the appropriate speakers as well. Some surround processors like a Fosgate Model 3 would decorrelate the surround channel to help create a more lifelike sound and things continue to develop from there. With Dolby AC-3's 5.1 and DTS and so on its a game of little post-processing.

    No idea about Matlab though.....

    Cliff
     
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