Alexandre Lision | 8af73cb | 2013-12-10 14:11:20 -0500 | [diff] [blame] | 1 | |
| 2 | /****************************************************************** |
| 3 | |
| 4 | iLBC Speech Coder ANSI-C Source Code |
| 5 | |
| 6 | FrameClassify.c |
| 7 | |
| 8 | Copyright (C) The Internet Society (2004). |
| 9 | All Rights Reserved. |
| 10 | |
| 11 | ******************************************************************/ |
| 12 | |
| 13 | #include "iLBC_define.h" |
| 14 | |
| 15 | /*---------------------------------------------------------------* |
| 16 | * Classification of subframes to localize start state |
| 17 | *--------------------------------------------------------------*/ |
| 18 | |
| 19 | int FrameClassify( /* index to the max-energy sub-frame */ |
| 20 | iLBC_Enc_Inst_t *iLBCenc_inst, |
| 21 | /* (i/o) the encoder state structure */ |
| 22 | float *residual /* (i) lpc residual signal */ |
| 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 | } |
| 114 | |