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  1. As the topic says, what is the difference? 'Cause I'm creating a lot of SVCDs and I wonder if I should use Dual Channel or Joint Stereo istead of normal Stereo for DVDs, that don't have DD 5.1 (If they got DD 5.1 I mostly use MPEG MC). I suggest that Dual Channel is Dolby Surround 2.0, but I am not sure and i haven't tested it yet. And also, which Quality to use? For stereo i use 192 kbits and for mpeg MC 384 kbits.
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  2. Член BJ_M's Avatar
    Join Date: Jul 2002
    Location: Canada
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    no - dual channel is not dolby surround ..

    The MPEG Audio standard has four modes:
    Mono
    Dual channel
    Stereo
    Intensity Stereo (also called Joint Stereo).
    Mono mode is the obvious choice for single channel audio work. To choose the mode for two-channel applications, first determine whether the left and right signals need to be separated into two different files so that you can work individually on the left or right channel. If this is the case, choose the Mono mode. If the two channels do not need to be operated upon independently, choose among Stereo, Dual channel or Intensity Stereo modes to create a single file. The Stereo or Dual Channel modes are identical from the perspective of the operation, as they generate a unique file for the stereo signal. However an indicator bit that identifies whether the file is in one or the other mode may be used by some applications. The Intensity Stereo (Joint Stereo) mode considers the redundancy between left and right channels to optimize coding. The subjective quality of Intensity Stereo varies with the stereo image of the coded signal. However, it is particularly well-suited to low bit rates, yielding better quality than with other modes, so its use should be reserved for applications, such as transmission, where low bit rate is a priority.
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  3. The difference between dual channel and stereo modes is that dual channel fixes the bitrate of each channel so that it is exactly half for the entire length of the audio.

    For example, for 224 kbit/s stereo audio, a dual channel encoded track will have exactly 112 kbit/s for the L channel and 112 kbit/s for the R.

    Standard stereo dynamically allocates bitrate to the channel that has "more need". For example, if L is silent and R has audio, it can allocate the majority of the combined bitrate to the R channel.

    Joint stereo encodes the audio with the redundancy between the L and R channel taken into acount. As joint stereo encoding can affect the phase information, it can negatively impact on Dolby Surround encoded stereo and is not recommended.

    I personally suggest that you just use "stereo". Some people claim that "dual channel" is better for Dolby Surround encoded material, but I certainly cannot hear it and it logically shouldn't really either.

    Regards.
    Michael Tam
    w: Morsels of Evidence
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