MFPKEY_WMAAECMA_FEATR_VAD Property

[アーティクル]
04/12/2010

Specifies the type of voice activity detection that the Voice Capture DSP performs.

Constant for IPropertyBag

Available only by using IPropertyStore.

Data Type

VT_I4

Default Value

Applies To

Voice Capture DSP

Remarks

The value of this property is a member of the AEC_VAD_MODE enumeration. The output from voice activity detection is a number from 0 to 3, calculated for each audio frame. The DSP encodes the result in the lowest bit of the first two audio samples in each audio frame. The meaning of the value depends on the specified mode.

The following code shows how to extract the results from the audio data. In this example, pOutput is a pointer to the start of an audio frame in the output data.

int AecDecodeVAD(short *pOutput)
{
    int iVAD = (*pOutput) & 0x01;
    pOutput++;
    iVAD |= (*pOutput << 1) & 0x02;
    return iVAD;
}

The default value of this property is 0 (disabled). Before setting this property, you must set the MFPKEY_WMAAECMA_FEATURE_MODE property to VARIANT_TRUE.

Requirements

Minimum supported client	Windows XP
Minimum supported server	Windows Server 2003
Header	Wmcodecdsp.h

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