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/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_mfcc_init_q15.c
* Description: MFCC initialization function for the q15 version
*
* $Date: 07 September 2021
* $Revision: V1.10.0
*
* Target Processor: Cortex-M and Cortex-A cores
* -------------------------------------------------------------------- */
/*
* Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved.
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the License); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an AS IS BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
@ingroup groupTransforms
*/
/**
@addtogroup MFCC
@{
*/
#include "dsp/transform_functions.h"
/**
@brief Initialization of the MFCC F32 instance structure
@param[out] S points to the mfcc instance structure
@param[in] fftLen fft length
@param[in] nbMelFilters number of Mel filters
@param[in] nbDctOutputs number of Dct outputs
@param[in] dctCoefs points to an array of DCT coefficients
@param[in] filterPos points of the array of filter positions
@param[in] filterLengths points to the array of filter lengths
@param[in] filterCoefs points to the array of filter coefficients
@param[in] windowCoefs points to the array of window coefficients
@return error status
@par 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_status arm_mfcc_init_q15(
arm_mfcc_instance_q15 * S,
uint32_t fftLen,
uint32_t nbMelFilters,
uint32_t nbDctOutputs,
const q15_t *dctCoefs,
const uint32_t *filterPos,
const uint32_t *filterLengths,
const q15_t *filterCoefs,
const q15_t *windowCoefs
)
{
arm_status status;
S->fftLen=fftLen;
S->nbMelFilters=nbMelFilters;
S->nbDctOutputs=nbDctOutputs;
S->dctCoefs=dctCoefs;
S->filterPos=filterPos;
S->filterLengths=filterLengths;
S->filterCoefs=filterCoefs;
S->windowCoefs=windowCoefs;
#if defined(ARM_MFCC_CFFT_BASED)
status=arm_cfft_init_q15(&(S->cfft),fftLen);
#else
status=arm_rfft_init_q15(&(S->rfft),fftLen,0,1);
#endif
return(status);
}
/**
@} end of MFCC group
*/
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