1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_mfcc_f32.c
4 * Description: MFCC function for the f32 version
5 *
6 * $Date: 07 September 2021
7 * $Revision: V1.10.0
8 *
9 * Target Processor: Cortex-M and Cortex-A cores
10 * -------------------------------------------------------------------- */
11 /*
12 * Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved.
13 *
14 * SPDX-License-Identifier: Apache-2.0
15 *
16 * Licensed under the Apache License, Version 2.0 (the License); you may
17 * not use this file except in compliance with the License.
18 * You may obtain a copy of the License at
19 *
20 * www.apache.org/licenses/LICENSE-2.0
21 *
22 * Unless required by applicable law or agreed to in writing, software
23 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
24 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
25 * See the License for the specific language governing permissions and
26 * limitations under the License.
27 */
28
29
30
31 #include "dsp/transform_functions.h"
32 #include "dsp/statistics_functions.h"
33 #include "dsp/basic_math_functions.h"
34 #include "dsp/complex_math_functions.h"
35 #include "dsp/fast_math_functions.h"
36 #include "dsp/matrix_functions.h"
37
38 /**
39 @ingroup MFCC
40 */
41
42
43
44 /**
45 @addtogroup MFCCF32
46 @{
47 */
48
49 /**
50 @brief MFCC F32
51 @param[in] S points to the mfcc instance structure
52 @param[in] pSrc points to the input samples
53 @param[out] pDst points to the output MFCC values
54 @param[inout] pTmp points to a temporary buffer of complex
55
56 @par Description
57 The number of input samples if the FFT length used
58 when initializing the instance data structure.
59
60 The temporary buffer has a 2*fft length size when MFCC
61 is implemented with CFFT.
62 It has length FFT Length + 2 when implemented with RFFT
63 (default implementation).
64
65 The source buffer is modified by this function.
66
67 */
arm_mfcc_f32(const arm_mfcc_instance_f32 * S,float32_t * pSrc,float32_t * pDst,float32_t * pTmp)68 void arm_mfcc_f32(
69 const arm_mfcc_instance_f32 * S,
70 float32_t *pSrc,
71 float32_t *pDst,
72 float32_t *pTmp
73 )
74 {
75 float32_t maxValue;
76 uint32_t index;
77 uint32_t i;
78 float32_t result;
79 const float32_t *coefs=S->filterCoefs;
80 arm_matrix_instance_f32 pDctMat;
81
82 /* Normalize */
83 arm_absmax_f32(pSrc,S->fftLen,&maxValue,&index);
84
85 if (maxValue != 0.0f)
86 {
87 arm_scale_f32(pSrc,1.0f/maxValue,pSrc,S->fftLen);
88 }
89
90 /* Multiply by window */
91 arm_mult_f32(pSrc,S->windowCoefs,pSrc,S->fftLen);
92
93 /* Compute spectrum magnitude
94 */
95 #if defined(ARM_MFCC_CFFT_BASED)
96 /* some HW accelerator for CMSIS-DSP used in some boards
97 are only providing acceleration for CFFT.
98 With ARM_MFCC_CFFT_BASED enabled, CFFT is used and the MFCC
99 will be accelerated on those boards.
100
101 The default is to use RFFT
102 */
103 /* Convert from real to complex */
104 for(i=0; i < S->fftLen ; i++)
105 {
106 pTmp[2*i] = pSrc[i];
107 pTmp[2*i+1] = 0.0f;
108 }
109 arm_cfft_f32(&(S->cfft),pTmp,0,1);
110 #else
111 /* Default RFFT based implementation */
112 arm_rfft_fast_f32(&(S->rfft),pSrc,pTmp,0);
113 /* Unpack real values */
114 pTmp[S->fftLen]=pTmp[1];
115 pTmp[S->fftLen+1]=0.0f;
116 pTmp[1]=0.0f;
117 #endif
118 arm_cmplx_mag_f32(pTmp,pSrc,S->fftLen);
119 if (maxValue != 0.0f)
120 {
121 arm_scale_f32(pSrc,maxValue,pSrc,S->fftLen);
122 }
123
124 /* Apply MEL filters */
125 for(i=0; i<S->nbMelFilters; i++)
126 {
127 arm_dot_prod_f32(pSrc+S->filterPos[i],
128 coefs,
129 S->filterLengths[i],
130 &result);
131
132 coefs += S->filterLengths[i];
133
134 pTmp[i] = result;
135
136 }
137
138 /* Compute the log */
139 arm_offset_f32(pTmp,1.0e-6f,pTmp,S->nbMelFilters);
140 arm_vlog_f32(pTmp,pTmp,S->nbMelFilters);
141
142 /* Multiply with the DCT matrix */
143
144 pDctMat.numRows=S->nbDctOutputs;
145 pDctMat.numCols=S->nbMelFilters;
146 pDctMat.pData=(float32_t*)S->dctCoefs;
147
148 arm_mat_vec_mult_f32(&pDctMat, pTmp, pDst);
149
150
151 }
152
153 /**
154 @} end of MFCCF32 group
155 */
156
