MFCC Q31

Functions
arm_status	arm_mfcc_init_q31 (arm_mfcc_instance_q31 *S, uint32_t fftLen, uint32_t nbMelFilters, uint32_t nbDctOutputs, const q31_t *dctCoefs, const uint32_t *filterPos, const uint32_t *filterLengths, const q31_t *filterCoefs, const q31_t *windowCoefs)
	Generic initialization of the MFCC Q31 instance structure. More...
arm_status	arm_mfcc_init_32_q31 (arm_mfcc_instance_q31 *S, uint32_t nbMelFilters, uint32_t nbDctOutputs, const q31_t *dctCoefs, const uint32_t *filterPos, const uint32_t *filterLengths, const q31_t *filterCoefs, const q31_t *windowCoefs)
	Initialization of the MFCC Q31 instance structure for 32 sample MFCC. More...
arm_status	arm_mfcc_init_64_q31 (arm_mfcc_instance_q31 *S, uint32_t nbMelFilters, uint32_t nbDctOutputs, const q31_t *dctCoefs, const uint32_t *filterPos, const uint32_t *filterLengths, const q31_t *filterCoefs, const q31_t *windowCoefs)
	Initialization of the MFCC Q31 instance structure for 64 sample MFCC. More...
arm_status	arm_mfcc_init_128_q31 (arm_mfcc_instance_q31 *S, uint32_t nbMelFilters, uint32_t nbDctOutputs, const q31_t *dctCoefs, const uint32_t *filterPos, const uint32_t *filterLengths, const q31_t *filterCoefs, const q31_t *windowCoefs)
	Initialization of the MFCC Q31 instance structure for 128 sample MFCC. More...
arm_status	arm_mfcc_init_256_q31 (arm_mfcc_instance_q31 *S, uint32_t nbMelFilters, uint32_t nbDctOutputs, const q31_t *dctCoefs, const uint32_t *filterPos, const uint32_t *filterLengths, const q31_t *filterCoefs, const q31_t *windowCoefs)
	Initialization of the MFCC Q31 instance structure for 256 sample MFCC. More...
arm_status	arm_mfcc_init_512_q31 (arm_mfcc_instance_q31 *S, uint32_t nbMelFilters, uint32_t nbDctOutputs, const q31_t *dctCoefs, const uint32_t *filterPos, const uint32_t *filterLengths, const q31_t *filterCoefs, const q31_t *windowCoefs)
	Initialization of the MFCC Q31 instance structure for 512 sample MFCC. More...
arm_status	arm_mfcc_init_1024_q31 (arm_mfcc_instance_q31 *S, uint32_t nbMelFilters, uint32_t nbDctOutputs, const q31_t *dctCoefs, const uint32_t *filterPos, const uint32_t *filterLengths, const q31_t *filterCoefs, const q31_t *windowCoefs)
	Initialization of the MFCC Q31 instance structure for 1024 sample MFCC. More...
arm_status	arm_mfcc_init_2048_q31 (arm_mfcc_instance_q31 *S, uint32_t nbMelFilters, uint32_t nbDctOutputs, const q31_t *dctCoefs, const uint32_t *filterPos, const uint32_t *filterLengths, const q31_t *filterCoefs, const q31_t *windowCoefs)
	Initialization of the MFCC Q31 instance structure for 2048 sample MFCC. More...
arm_status	arm_mfcc_init_4096_q31 (arm_mfcc_instance_q31 *S, uint32_t nbMelFilters, uint32_t nbDctOutputs, const q31_t *dctCoefs, const uint32_t *filterPos, const uint32_t *filterLengths, const q31_t *filterCoefs, const q31_t *windowCoefs)
	Initialization of the MFCC Q31 instance structure for 4096 sample MFCC. More...
arm_status	arm_mfcc_q31 (const arm_mfcc_instance_q31 *S, q31_t *pSrc, q31_t *pDst, q31_t *pTmp)
	MFCC Q31. More...

Description

Function Documentation

arm_mfcc_init_1024_q31()

arm_status arm_mfcc_init_1024_q31	(	arm_mfcc_instance_q31 *	S,
		uint32_t	nbMelFilters,
		uint32_t	nbDctOutputs,
		const q31_t *	dctCoefs,
		const uint32_t *	filterPos,
		const uint32_t *	filterLengths,
		const q31_t *	filterCoefs,
		const q31_t *	windowCoefs
	)

Parameters

[out]	S	points to the mfcc instance structure
[in]	nbMelFilters	number of Mel filters
[in]	nbDctOutputs	number of Dct outputs
[in]	dctCoefs	points to an array of DCT coefficients
[in]	filterPos	points of the array of filter positions
[in]	filterLengths	points to the array of filter lengths
[in]	filterCoefs	points to the array of filter coefficients
[in]	windowCoefs	points to the array of window coefficients

Returns

error status

Description

The matrix of Mel filter coefficients is sparse. Most of the coefficients are zero. To avoid multiplying the spectrogram by those zeros, the filter is applied only to a given position in the spectrogram and on a given number of FFT bins (the filter length). It is the reason for the arrays filterPos and filterLengths.

window coefficients can describe (for instance) a Hamming window. The array has the same size as the FFT length.

The folder Scripts is containing a Python script which can be used to generate the filter, dct and window arrays.

arm_mfcc_init_128_q31()

arm_status arm_mfcc_init_128_q31	(	arm_mfcc_instance_q31 *	S,
		uint32_t	nbMelFilters,
		uint32_t	nbDctOutputs,
		const q31_t *	dctCoefs,
		const uint32_t *	filterPos,
		const uint32_t *	filterLengths,
		const q31_t *	filterCoefs,
		const q31_t *	windowCoefs
	)

Parameters

[out]	S	points to the mfcc instance structure
[in]	nbMelFilters	number of Mel filters
[in]	nbDctOutputs	number of Dct outputs
[in]	dctCoefs	points to an array of DCT coefficients
[in]	filterPos	points of the array of filter positions
[in]	filterLengths	points to the array of filter lengths
[in]	filterCoefs	points to the array of filter coefficients
[in]	windowCoefs	points to the array of window coefficients

Returns

error status

Description

The matrix of Mel filter coefficients is sparse. Most of the coefficients are zero. To avoid multiplying the spectrogram by those zeros, the filter is applied only to a given position in the spectrogram and on a given number of FFT bins (the filter length). It is the reason for the arrays filterPos and filterLengths.

window coefficients can describe (for instance) a Hamming window. The array has the same size as the FFT length.

The folder Scripts is containing a Python script which can be used to generate the filter, dct and window arrays.

arm_mfcc_init_2048_q31()

arm_status arm_mfcc_init_2048_q31	(	arm_mfcc_instance_q31 *	S,
		uint32_t	nbMelFilters,
		uint32_t	nbDctOutputs,
		const q31_t *	dctCoefs,
		const uint32_t *	filterPos,
		const uint32_t *	filterLengths,
		const q31_t *	filterCoefs,
		const q31_t *	windowCoefs
	)

Parameters

[out]	S	points to the mfcc instance structure
[in]	nbMelFilters	number of Mel filters
[in]	nbDctOutputs	number of Dct outputs
[in]	dctCoefs	points to an array of DCT coefficients
[in]	filterPos	points of the array of filter positions
[in]	filterLengths	points to the array of filter lengths
[in]	filterCoefs	points to the array of filter coefficients
[in]	windowCoefs	points to the array of window coefficients

Returns

error status

Description

The matrix of Mel filter coefficients is sparse. Most of the coefficients are zero. To avoid multiplying the spectrogram by those zeros, the filter is applied only to a given position in the spectrogram and on a given number of FFT bins (the filter length). It is the reason for the arrays filterPos and filterLengths.

window coefficients can describe (for instance) a Hamming window. The array has the same size as the FFT length.

The folder Scripts is containing a Python script which can be used to generate the filter, dct and window arrays.

arm_mfcc_init_256_q31()

arm_status arm_mfcc_init_256_q31	(	arm_mfcc_instance_q31 *	S,
		uint32_t	nbMelFilters,
		uint32_t	nbDctOutputs,
		const q31_t *	dctCoefs,
		const uint32_t *	filterPos,
		const uint32_t *	filterLengths,
		const q31_t *	filterCoefs,
		const q31_t *	windowCoefs
	)

Parameters

[out]	S	points to the mfcc instance structure
[in]	nbMelFilters	number of Mel filters
[in]	nbDctOutputs	number of Dct outputs
[in]	dctCoefs	points to an array of DCT coefficients
[in]	filterPos	points of the array of filter positions
[in]	filterLengths	points to the array of filter lengths
[in]	filterCoefs	points to the array of filter coefficients
[in]	windowCoefs	points to the array of window coefficients

Returns

error status

Description

The matrix of Mel filter coefficients is sparse. Most of the coefficients are zero. To avoid multiplying the spectrogram by those zeros, the filter is applied only to a given position in the spectrogram and on a given number of FFT bins (the filter length). It is the reason for the arrays filterPos and filterLengths.

window coefficients can describe (for instance) a Hamming window. The array has the same size as the FFT length.

The folder Scripts is containing a Python script which can be used to generate the filter, dct and window arrays.

arm_mfcc_init_32_q31()

arm_status arm_mfcc_init_32_q31	(	arm_mfcc_instance_q31 *	S,
		uint32_t	nbMelFilters,
		uint32_t	nbDctOutputs,
		const q31_t *	dctCoefs,
		const uint32_t *	filterPos,
		const uint32_t *	filterLengths,
		const q31_t *	filterCoefs,
		const q31_t *	windowCoefs
	)

Parameters

[out]	S	points to the mfcc instance structure
[in]	nbMelFilters	number of Mel filters
[in]	nbDctOutputs	number of Dct outputs
[in]	dctCoefs	points to an array of DCT coefficients
[in]	filterPos	points of the array of filter positions
[in]	filterLengths	points to the array of filter lengths
[in]	filterCoefs	points to the array of filter coefficients
[in]	windowCoefs	points to the array of window coefficients

Returns

error status

Description

The matrix of Mel filter coefficients is sparse. Most of the coefficients are zero. To avoid multiplying the spectrogram by those zeros, the filter is applied only to a given position in the spectrogram and on a given number of FFT bins (the filter length). It is the reason for the arrays filterPos and filterLengths.

window coefficients can describe (for instance) a Hamming window. The array has the same size as the FFT length.

The folder Scripts is containing a Python script which can be used to generate the filter, dct and window arrays.

arm_mfcc_init_4096_q31()

arm_status arm_mfcc_init_4096_q31	(	arm_mfcc_instance_q31 *	S,
		uint32_t	nbMelFilters,
		uint32_t	nbDctOutputs,
		const q31_t *	dctCoefs,
		const uint32_t *	filterPos,
		const uint32_t *	filterLengths,
		const q31_t *	filterCoefs,
		const q31_t *	windowCoefs
	)

Parameters

[out]	S	points to the mfcc instance structure
[in]	nbMelFilters	number of Mel filters
[in]	nbDctOutputs	number of Dct outputs
[in]	dctCoefs	points to an array of DCT coefficients
[in]	filterPos	points of the array of filter positions
[in]	filterLengths	points to the array of filter lengths
[in]	filterCoefs	points to the array of filter coefficients
[in]	windowCoefs	points to the array of window coefficients

Returns

error status

Description

The matrix of Mel filter coefficients is sparse. Most of the coefficients are zero. To avoid multiplying the spectrogram by those zeros, the filter is applied only to a given position in the spectrogram and on a given number of FFT bins (the filter length). It is the reason for the arrays filterPos and filterLengths.

window coefficients can describe (for instance) a Hamming window. The array has the same size as the FFT length.

The folder Scripts is containing a Python script which can be used to generate the filter, dct and window arrays.

arm_mfcc_init_512_q31()

arm_status arm_mfcc_init_512_q31	(	arm_mfcc_instance_q31 *	S,
		uint32_t	nbMelFilters,
		uint32_t	nbDctOutputs,
		const q31_t *	dctCoefs,
		const uint32_t *	filterPos,
		const uint32_t *	filterLengths,
		const q31_t *	filterCoefs,
		const q31_t *	windowCoefs
	)

Parameters

[out]	S	points to the mfcc instance structure
[in]	nbMelFilters	number of Mel filters
[in]	nbDctOutputs	number of Dct outputs
[in]	dctCoefs	points to an array of DCT coefficients
[in]	filterPos	points of the array of filter positions
[in]	filterLengths	points to the array of filter lengths
[in]	filterCoefs	points to the array of filter coefficients
[in]	windowCoefs	points to the array of window coefficients

Returns

error status

Description

The matrix of Mel filter coefficients is sparse. Most of the coefficients are zero. To avoid multiplying the spectrogram by those zeros, the filter is applied only to a given position in the spectrogram and on a given number of FFT bins (the filter length). It is the reason for the arrays filterPos and filterLengths.

window coefficients can describe (for instance) a Hamming window. The array has the same size as the FFT length.

The folder Scripts is containing a Python script which can be used to generate the filter, dct and window arrays.

arm_mfcc_init_64_q31()

arm_status arm_mfcc_init_64_q31	(	arm_mfcc_instance_q31 *	S,
		uint32_t	nbMelFilters,
		uint32_t	nbDctOutputs,
		const q31_t *	dctCoefs,
		const uint32_t *	filterPos,
		const uint32_t *	filterLengths,
		const q31_t *	filterCoefs,
		const q31_t *	windowCoefs
	)

Parameters

[out]	S	points to the mfcc instance structure
[in]	nbMelFilters	number of Mel filters
[in]	nbDctOutputs	number of Dct outputs
[in]	dctCoefs	points to an array of DCT coefficients
[in]	filterPos	points of the array of filter positions
[in]	filterLengths	points to the array of filter lengths
[in]	filterCoefs	points to the array of filter coefficients
[in]	windowCoefs	points to the array of window coefficients

Returns

error status

Description

The matrix of Mel filter coefficients is sparse. Most of the coefficients are zero. To avoid multiplying the spectrogram by those zeros, the filter is applied only to a given position in the spectrogram and on a given number of FFT bins (the filter length). It is the reason for the arrays filterPos and filterLengths.

window coefficients can describe (for instance) a Hamming window. The array has the same size as the FFT length.

The folder Scripts is containing a Python script which can be used to generate the filter, dct and window arrays.

arm_mfcc_init_q31()

arm_status arm_mfcc_init_q31	(	arm_mfcc_instance_q31 *	S,
		uint32_t	fftLen,
		uint32_t	nbMelFilters,
		uint32_t	nbDctOutputs,
		const q31_t *	dctCoefs,
		const uint32_t *	filterPos,
		const uint32_t *	filterLengths,
		const q31_t *	filterCoefs,
		const q31_t *	windowCoefs
	)

Parameters

[out]	S	points to the mfcc instance structure
[in]	fftLen	fft length
[in]	nbMelFilters	number of Mel filters
[in]	nbDctOutputs	number of Dct outputs
[in]	dctCoefs	points to an array of DCT coefficients
[in]	filterPos	points of the array of filter positions
[in]	filterLengths	points to the array of filter lengths
[in]	filterCoefs	points to the array of filter coefficients
[in]	windowCoefs	points to the array of window coefficients

Returns

error status

Description

The matrix of Mel filter coefficients is sparse. Most of the coefficients are zero. To avoid multiplying the spectrogram by those zeros, the filter is applied only to a given position in the spectrogram and on a given number of FFT bins (the filter length). It is the reason for the arrays filterPos and filterLengths.

window coefficients can describe (for instance) a Hamming window. The array has the same size as the FFT length.

The folder Scripts is containing a Python script which can be used to generate the filter, dct and window arrays.

This function should be used only if you don't know the FFT sizes that you'll need at build time. The use of this function will prevent the linker from removing the FFT tables that are not needed and the library code size will be bigger than needed.

If you use CMSIS-DSP as a static library, and if you know the MFCC sizes that you need at build time, then it is better to use the initialization functions defined for each MFCC size.

arm_mfcc_q31()

arm_status arm_mfcc_q31	(	const arm_mfcc_instance_q31 *	S,
		q31_t *	pSrc,
		q31_t *	pDst,
		q31_t *	pTmp
	)

Parameters

[in]	S	points to the mfcc instance structure
[in]	pSrc	points to the input samples in Q31
[out]	pDst	points to the output MFCC values in q8.23 format
[in,out]	pTmp	points to a temporary buffer of complex

Returns

none

Description

The number of input samples is the FFT length used when initializing the instance data structure.

The temporary buffer has a 2*fft length.

The source buffer is modified by this function.

The function may saturate. If the FFT length is too big and the number of MEL filters too small then the fixed point computations may saturate.