VAD API functions

Functions
VAD_API VAD_Handle	VAD_setup ()
VAD_API int_least16_t	VAD_getInitFrames (VAD_Handle handle)
VAD_API void	VAD_setInitFrames (VAD_Handle handle, int_least16_t initFrames)
VAD_API int_least16_t	VAD_getDelayFrames (VAD_Handle handle)
VAD_API void	VAD_setDelayFrames (VAD_Handle handle, int_least16_t delayFrames)
VAD_API int_least16_t	VAD_getAlpha (VAD_Handle handle)
VAD_API void	VAD_setAlpha (VAD_Handle handle, int_least16_t alpha)
VAD_API int_least16_t	VAD_getFastCoef (VAD_Handle handle)
VAD_API void	VAD_setFastCoef (VAD_Handle handle, int_least16_t fastCoef)
VAD_API int_least16_t	VAD_getSlowCoef (VAD_Handle handle)
VAD_API void	VAD_setSlowCoef (VAD_Handle handle, int_least16_t slowCoef)
VAD_API int_least16_t	VAD_getSignalFloor (VAD_Handle handle)
VAD_API void	VAD_setSignalFloor (VAD_Handle handle, int_least32_t signalFloor)
VAD_API int_least16_t	VAD_getNoiseFloor (VAD_Handle handle)
VAD_API void	VAD_setNoiseFloor (VAD_Handle handle, int_least32_t noiseFloor)
VAD_API int_least16_t	VAD_getSigSNRThresh (VAD_Handle handle)
VAD_API void	VAD_setSigSNRThresh (VAD_Handle handle, int_least16_t sigSNRThresh)
VAD_API int_least16_t	VAD_getSigSNRLimit (VAD_Handle handle)
VAD_API void	VAD_setSigSNRLimit (VAD_Handle handle, int_least16_t sigSNRLimit)
VAD_API int_least16_t	VAD_getNoiseRate (VAD_Handle handle)
VAD_API void	VAD_setNoiseRate (VAD_Handle handle, int_least16_t noiseRate)
VAD_API VAD_MessageEnum	VAD_run (VAD_Handle handle, int_least16_t rmsegy)
VAD_API const char *	VAD_getVersion (void)

Detailed Description

Functions of the VAD API

Function Documentation

VAD_API VAD_Handle VAD_setup

(

)

Initialize the VAD object prior to starting detection. Prepares the VAD object to start detecting audio events. It must be called before any other VAD functions including get/set functions. Returns handle to VAD object.

Returns

VAD handle

VAD_API int_least16_t VAD_getInitFrames

(

VAD_Handle

handle

)

Gets the initialization stabilization duration in frames. Get initialization stabilization duration in frames.

Parameters

[in]

handle

VAD handle

Returns

Number of initialization frames

VAD_API void VAD_setInitFrames	(	VAD_Handle	handle,
		int_least16_t	initFrames
	)

Sets the the initialization stabilization duration in frames. Set initialization stabilization duration in frames.
0 < initFrames <= INT16_MAX

Parameters

[in]	handle	VAD handle
[in]	initFrames	Initialization frames

VAD_API int_least16_t VAD_getDelayFrames

(

VAD_Handle

handle

)

Gets number of sequential frames above noise to declare activity. Get sequential frames above noise to declare activity.

Parameters

[in]

handle

VAD handle

Returns

Number of delay frames

VAD_API void VAD_setDelayFrames	(	VAD_Handle	handle,
		int_least16_t	delayFrames
	)

Sets number of sequential frames above noise to declare activity. Set sequential frames above noise to declare activity.
0 < delayFrames <= INT16_MAX

Parameters

[in]	handle	VAD handle
[in]	delayFrames	Delay frames

VAD_API int_least16_t VAD_getAlpha

(

VAD_Handle

handle

)

Gets smoothed signal energy filter coefficient alpha. Get smoothed signal energy filter coefficient alpha

Parameters

[in]

handle

VAD handle

Returns

smoothing filter coefficient alpha (Q15)

VAD_API void VAD_setAlpha	(	VAD_Handle	handle,
		int_least16_t	alpha
	)

Sets smoothed signal energy filter coefficient alpha. Set smoothed signal energy filter coefficient alpha (Q15).
0 < alpha <= INT16_MAX

Parameters

[in]	handle	VAD handle
[in]	alpha	Smoothing filter coefficient alpha

VAD_API int_least16_t VAD_getFastCoef

(

VAD_Handle

handle

)

Gets fast activity estimator filter coefficient. Get fast activity estimator filter coefficient (Q15).

Parameters

[in]

handle

VAD handle

Returns

fast activity estimator filter coefficient (Q15)

VAD_API void VAD_setFastCoef	(	VAD_Handle	handle,
		int_least16_t	fastCoef
	)

Sets fast activity estimator filter coefficient. Set fast activity estimator filter coefficient (Q15).
0 < fastCoef <= INT16_MAX

Parameters

[in]	handle	VAD handle
[in]	fastCoef	Fast activity estimator filter coefficient;

VAD_API int_least16_t VAD_getSlowCoef

(

VAD_Handle

handle

)

Gets slow activity estimator filter coefficient. Gets slow activity estimator filter coefficient (Q15).

Parameters

[in]

handle

VAD handle

Returns

slow activity estimator filter coefficient (Q15)

VAD_API void VAD_setSlowCoef	(	VAD_Handle	handle,
		int_least16_t	slowCoef
	)

Sets slow activity estimator filter coefficient. Set slow activity estimator filter coefficient (Q15).
0 < slowCoef <= INT16_MAX

Parameters

[in]	handle	VAD handle
[in]	slowCoef	Slow activity estimator filter coefficient;

VAD_API int_least16_t VAD_getSignalFloor

(

VAD_Handle

handle

)

Gets signal RMS energy floor.

Parameters

[in]

handle

VAD handle

Returns

signal rms energy floor (Q30)

VAD_API void VAD_setSignalFloor	(	VAD_Handle	handle,
		int_least32_t	signalFloor
	)

Sets signal RMS energy floor. Set signal RMS energy floor in (Q30).
0 < signalFloor <= INT32_MAX

Parameters

[in]	handle	VAD handle
[in]	signalFloor	Signal rms energy floor in (Q30);

VAD_API int_least16_t VAD_getNoiseFloor

(

VAD_Handle

handle

)

Gets noise RMS energy floor. Gets noise RMS energy floor in (Q30).

Parameters

[in]

handle

VAD handle

Returns

noise RMS energy floor (Q30)

VAD_API void VAD_setNoiseFloor	(	VAD_Handle	handle,
		int_least32_t	noiseFloor
	)

Sets noise RMS energy floor. Set noise RMS energy floor in (Q30).
0 < noiseFloor <= INT32_MAX

Parameters

[in]	handle	VAD handle
[in]	noiseFloor	Noise RMS energy floor in (Q30);

VAD_API int_least16_t VAD_getSigSNRThresh

(

VAD_Handle

handle

)

Gets signal SNR threshold. Get signal SNR threshold (Q10)

Parameters

[in]

handle

VAD handle

Returns

signal SNR threshold (Q10)

VAD_API void VAD_setSigSNRThresh	(	VAD_Handle	handle,
		int_least16_t	sigSNRThresh
	)

Sets signal SNR threshold. Sets signal SNR threshold (Q10).
0 < sigSNRThresh <= INT16_MAX

Parameters

[in]	handle	VAD handle
[in]	sigSNRThresh	Signal SNR threshold (Q10);

VAD_API int_least16_t VAD_getSigSNRLimit

(

VAD_Handle

handle

)

Gets signal SNR Limit. Get signal SNR Limit (Q10)

Parameters

[in]

handle

VAD handle

Returns

signal SNR limit (Q10)

VAD_API void VAD_setSigSNRLimit	(	VAD_Handle	handle,
		int_least16_t	sigSNRLimit
	)

Sets signal SNR limit. Set signal SNR limit (Q10).
0 < sigSNRLimit <= INT16_MAX

Parameters

[in]	handle	VAD handle
[in]	sigSNRLimit	SNR limit (Q10)

VAD_API int_least16_t VAD_getNoiseRate

(

VAD_Handle

handle

)

Get noise floor maximum upward adaptation rate multiplier (Q14). Gets noise floor maximum upward adaptation rate multiplier (Q14).

Parameters

[in]

handle

VAD handle

Returns

upward adaptation rate (Q14)

VAD_API void VAD_setNoiseRate	(	VAD_Handle	handle,
		int_least16_t	noiseRate
	)

Set noise floor maximum upward adaptation rate multiplier. Sets noise floor maximum upward adaptation rate multiplier (Q14).
0 < noiseRate <= INT16_MAX

Parameters

[in]	handle	VAD handle
[in]	noiseRate	Noise maximum upward rate (Q14);

VAD_API VAD_MessageEnum VAD_run	(	VAD_Handle	handle,
		int_least16_t	rmsegy
	)

Performs voice activity detection. Runs the voice activity detector for one frame returning result. The declaration that speech is found will be delayed by delayFrames seconds from when speech actually started. The parameter rmsegy is the average rms energy in the frame of data in Q15, normalized to a peak rms energy of 1.0 (32767 in Q15). For each frame, VAD returns a message indicating the status of the VAD result. During non-speech it returns VAD_Background. When it detects some signal above the background noise it returns VAD_Hang. If this continues long enough to declare a speech signal found it will return VAD_Detect for one frame. Thereafter, as long as the speech signal continues, it will return VAD_Ongoing. At the end of the utterance it will return to VAD_Background.

Parameters

[in]	handle	VAD handle
[in]	rmsegy	Normalized frame RMS energy (Q15)

Returns

VAD message indicating status as of the input frame

VAD_API const char* VAD_getVersion

(

void

)

Get VAD library version number.

Returns

Pointer to string that contains VAD library version.