Asterisk - The Open Source Telephony Project  18.5.0
Functions
FrameClassify.c File Reference
#include "iLBC_define.h"
Include dependency graph for FrameClassify.c:

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Functions

int FrameClassify (iLBC_Enc_Inst_t *iLBCenc_inst, float *residual)
 

Function Documentation

◆ FrameClassify()

int FrameClassify ( iLBC_Enc_Inst_t iLBCenc_inst,
float *  residual 
)

Definition at line 19 of file FrameClassify.c.

References iLBC_Enc_Inst_t_::mode, iLBC_Enc_Inst_t_::nsub, NSUB_MAX, and SUBL.

Referenced by iLBC_encode().

23  {
24  float max_ssqEn, fssqEn[NSUB_MAX], bssqEn[NSUB_MAX], *pp;
25  int n, l, max_ssqEn_n;
26  const float ssqEn_win[NSUB_MAX-1]={(float)0.8,(float)0.9,
27  (float)1.0,(float)0.9,(float)0.8};
28  const float sampEn_win[5]={(float)1.0/(float)6.0,
29  (float)2.0/(float)6.0, (float)3.0/(float)6.0,
30  (float)4.0/(float)6.0, (float)5.0/(float)6.0};
31 
32  /* init the front and back energies to zero */
33 
34  memset(fssqEn, 0, NSUB_MAX*sizeof(float));
35  memset(bssqEn, 0, NSUB_MAX*sizeof(float));
36 
37  /* Calculate front of first seqence */
38 
39  n=0;
40  pp=residual;
41  for (l=0; l<5; l++) {
42  fssqEn[n] += sampEn_win[l] * (*pp) * (*pp);
43  pp++;
44  }
45  for (l=5; l<SUBL; l++) {
46 
47 
48 
49 
50 
51  fssqEn[n] += (*pp) * (*pp);
52  pp++;
53  }
54 
55  /* Calculate front and back of all middle sequences */
56 
57  for (n=1; n<iLBCenc_inst->nsub-1; n++) {
58  pp=residual+n*SUBL;
59  for (l=0; l<5; l++) {
60  fssqEn[n] += sampEn_win[l] * (*pp) * (*pp);
61  bssqEn[n] += (*pp) * (*pp);
62  pp++;
63  }
64  for (l=5; l<SUBL-5; l++) {
65  fssqEn[n] += (*pp) * (*pp);
66  bssqEn[n] += (*pp) * (*pp);
67  pp++;
68  }
69  for (l=SUBL-5; l<SUBL; l++) {
70  fssqEn[n] += (*pp) * (*pp);
71  bssqEn[n] += sampEn_win[SUBL-l-1] * (*pp) * (*pp);
72  pp++;
73  }
74  }
75 
76  /* Calculate back of last seqence */
77 
78  n=iLBCenc_inst->nsub-1;
79  pp=residual+n*SUBL;
80  for (l=0; l<SUBL-5; l++) {
81  bssqEn[n] += (*pp) * (*pp);
82  pp++;
83  }
84  for (l=SUBL-5; l<SUBL; l++) {
85  bssqEn[n] += sampEn_win[SUBL-l-1] * (*pp) * (*pp);
86  pp++;
87  }
88 
89  /* find the index to the weighted 80 sample with
90  most energy */
91 
92  if (iLBCenc_inst->mode==20) l=1;
93  else l=0;
94 
95  max_ssqEn=(fssqEn[0]+bssqEn[1])*ssqEn_win[l];
96  max_ssqEn_n=1;
97  for (n=2; n<iLBCenc_inst->nsub; n++) {
98 
99 
100 
101 
102 
103 
104  l++;
105  if ((fssqEn[n-1]+bssqEn[n])*ssqEn_win[l] > max_ssqEn) {
106  max_ssqEn=(fssqEn[n-1]+bssqEn[n]) *
107  ssqEn_win[l];
108  max_ssqEn_n=n;
109  }
110  }
111 
112  return max_ssqEn_n;
113  }
#define SUBL
Definition: iLBC_define.h:33
#define NSUB_MAX
Definition: iLBC_define.h:24