DVD_MUA_Coeff Structure

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Microsoft DirectShow 9.0

DVD_MUA_Coeff Structure

The DVD_MUA_Coeff structure defines the mixing coefficients for one channel in a multichannel audio stream. The DVD_MultichannelAudioAttributes structure contains an array of eight DVD_MUA_Coeff structures, one for each channel in the stream.

Syntax

typedef struct tagDVD_MUA_Coeff {
    double   log2_alpha; 
    double   log2_beta;  
} DVD_MUA_Coeff;

Members

log2_alpha

Variable of type double indicating the mixing coefficient for this channel to channel 0.

log2_beta

Variable of type double indicating the mixing coefficient for this channel to channel 1.

Remarks

The information contained in this structure reflects the mixing coefficients as authored on the digital video disc (DVD). An application cannot modify these values or otherwise use them unless it is also decoding the audio. In the typical DVD filter graph, the DVD Navigator filter does not send this information to the decoder.

The alpha coefficient is used to mix to audio channel 0 and the beta coefficient is used to mix to audio channel 1. In general, the following formula calculates the mixing coefficients.

Audio channel 0 = coeff[0].alpha * value[0] + coeff[1].alpha * value[1] + ... 
Audio channel 1 = coeff[0].beta * value[0]  + coeff[1].beta * value[1] + ...

Requirements

Header: Dshow.h.

See Also