Feature Extraction

Spectral feature extraction functions. More...

Data Structures
struct	SpectrogramTypeDef
	Instance structure for the floating-point Spectrogram function. More...
struct	MelSpectrogramTypeDef
	Instance structure for the floating-point MelSpectrogram function. More...
struct	LogMelSpectrogramTypeDef
	Instance structure for the floating-point Log-MelSpectrogram function. More...
struct	MfccTypeDef
	Instance structure for the floating-point Mfcc function. More...

Enumerations
enum	Spectrogram_TypeTypedef { SPECTRUM_TYPE_MAGNITUDE , SPECTRUM_TYPE_POWER }
	Spectrum types. More...
enum	LogMelSpectrogram_ScaleTypedef { LOGMELSPECTROGRAM_SCALE_DB , LOGMELSPECTROGRAM_SCALE_LOG }
	LogMel Spectrum decibel conversion formula. More...

Functions
void	buf_to_float (int16_t *pInSignal, float32_t *pOutSignal, uint32_t len)
	Convert 16-bit PCM into floating point values.
void	buf_to_float_normed (int16_t *pInSignal, float32_t *pOutSignal, uint32_t len)
	Convert 16-bit PCM into normalized floating point values.
void	SpectrogramColumn (SpectrogramTypeDef *S, float32_t *pInSignal, float32_t *pOutCol)
	Power Spectrogram column.
void	MelSpectrogramColumn (MelSpectrogramTypeDef *S, float32_t *pInSignal, float32_t *pOutCol)
	Mel Spectrogram column.
void	LogMelSpectrogramColumn (LogMelSpectrogramTypeDef *S, float32_t *pInSignal, float32_t *pOutCol)
	Log-Mel Spectrogram column.
void	LogMelSpectrogramColumn_q15_Q8 (LogMelSpectrogramTypeDef *S, int16_t *pInSignal, int8_t *pOutCol, int8_t offset, float32_t inv_scale)
void	MfccColumn (MfccTypeDef *S, float32_t *pInSignal, float32_t *pOutCol)
	Mel-Frequency Cepstral Coefficients (MFCCs) column.
void	SpectrogramColumn_pad (SpectrogramTypeDef *S, float32_t *pInSignal, float32_t *pOutCol)

Detailed Description

Spectral feature extraction functions.

Enumeration Type Documentation

LogMelSpectrogram_ScaleTypedef

enum LogMelSpectrogram_ScaleTypedef

LogMel Spectrum decibel conversion formula.

Enumerator
LOGMELSPECTROGRAM_SCALE_DB	return mel energies using decibel scale (librosa)
LOGMELSPECTROGRAM_SCALE_LOG	return mel energies using natural log scale (TensorFlow)

Spectrogram_TypeTypedef

enum Spectrogram_TypeTypedef

Spectrum types.

Enumerator
SPECTRUM_TYPE_MAGNITUDE	magnitude spectrum
SPECTRUM_TYPE_POWER	squared magnitude spectrum

Function Documentation

buf_to_float()

void buf_to_float	(	int16_t *	pInSignal,
		float32_t *	pOutSignal,
		uint32_t	len
	)

Convert 16-bit PCM into floating point values.

Parameters

*pInSignal	points to input signal buffer
*pOutSignal	points to output signal buffer
len	signal length

buf_to_float_normed()

void buf_to_float_normed	(	int16_t *	pInSignal,
		float32_t *	pOutSignal,
		uint32_t	len
	)

Convert 16-bit PCM into normalized floating point values.

Parameters

*pInSignal	points to input signal buffer
*pOutSignal	points to output signal buffer
len	signal length

LogMelSpectrogramColumn()

void LogMelSpectrogramColumn	(	LogMelSpectrogramTypeDef *	S,
		float32_t *	pInSignal,
		float32_t *	pOutCol
	)

Log-Mel Spectrogram column.

Parameters

*S	points to an instance of the floating-point Log-Mel structure.
*pInSignal	points to input signal frame of length FFTLen.
*pOutCol	points to output Log-Mel Spectrogram column.

Returns

None

MelSpectrogramColumn()

void MelSpectrogramColumn	(	MelSpectrogramTypeDef *	S,
		float32_t *	pInSignal,
		float32_t *	pOutCol
	)

Mel Spectrogram column.

Parameters

*S	points to an instance of the floating-point Mel structure.
*pInSignal	points to input signal frame of length FFTLen.
*pOutCol	points to output Mel Spectrogram column.

Returns

None

MfccColumn()

void MfccColumn	(	MfccTypeDef *	S,
		float32_t *	pInSignal,
		float32_t *	pOutCol
	)

Mel-Frequency Cepstral Coefficients (MFCCs) column.

Parameters

*S	points to an instance of the floating-point MFCC structure.
*pInSignal	points to input signal frame of length FFTLen.
*pOutCol	points to output MFCC spectrogram column.

Returns

None

SpectrogramColumn()

void SpectrogramColumn	(	SpectrogramTypeDef *	S,
		float32_t *	pInSignal,
		float32_t *	pOutCol
	)

Power Spectrogram column.

Parameters

*S	points to an instance of the floating-point Spectrogram structure.
*pInSignal	points to the in-place input signal frame of length FFTLen.
*pOutCol	points to output Spectrogram column.

Returns

None