Mercurial > hg > audiostuff
comparison intercom/ilbc/FrameClassify.c @ 2:13be24d74cd2
import intercom-0.4.1
| author | Peter Meerwald <pmeerw@cosy.sbg.ac.at> |
|---|---|
| date | Fri, 25 Jun 2010 09:57:52 +0200 |
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| 1:9cadc470e3da | 2:13be24d74cd2 |
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| 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 { | |
| 25 float max_ssqEn, fssqEn[NSUB_MAX], bssqEn[NSUB_MAX], *pp; | |
| 26 int n, l, max_ssqEn_n; | |
| 27 const float ssqEn_win[NSUB_MAX - 1] = { (float) 0.8, (float) 0.9, | |
| 28 (float) 1.0, (float) 0.9, (float) 0.8 | |
| 29 }; | |
| 30 const float sampEn_win[5] = { (float) 1.0 / (float) 6.0, | |
| 31 (float) 2.0 / (float) 6.0, (float) 3.0 / (float) 6.0, | |
| 32 (float) 4.0 / (float) 6.0, (float) 5.0 / (float) 6.0 | |
| 33 }; | |
| 34 | |
| 35 /* init the front and back energies to zero */ | |
| 36 | |
| 37 memset(fssqEn, 0, NSUB_MAX * sizeof(float)); | |
| 38 memset(bssqEn, 0, NSUB_MAX * sizeof(float)); | |
| 39 | |
| 40 /* Calculate front of first seqence */ | |
| 41 | |
| 42 n = 0; | |
| 43 pp = residual; | |
| 44 for (l = 0; l < 5; l++) { | |
| 45 fssqEn[n] += sampEn_win[l] * (*pp) * (*pp); | |
| 46 pp++; | |
| 47 } | |
| 48 for (l = 5; l < SUBL; l++) { | |
| 49 | |
| 50 | |
| 51 | |
| 52 | |
| 53 | |
| 54 fssqEn[n] += (*pp) * (*pp); | |
| 55 pp++; | |
| 56 } | |
| 57 | |
| 58 /* Calculate front and back of all middle sequences */ | |
| 59 | |
| 60 for (n = 1; n < iLBCenc_inst->nsub - 1; n++) { | |
| 61 pp = residual + n * SUBL; | |
| 62 for (l = 0; l < 5; l++) { | |
| 63 fssqEn[n] += sampEn_win[l] * (*pp) * (*pp); | |
| 64 bssqEn[n] += (*pp) * (*pp); | |
| 65 pp++; | |
| 66 } | |
| 67 for (l = 5; l < SUBL - 5; l++) { | |
| 68 fssqEn[n] += (*pp) * (*pp); | |
| 69 bssqEn[n] += (*pp) * (*pp); | |
| 70 pp++; | |
| 71 } | |
| 72 for (l = SUBL - 5; l < SUBL; l++) { | |
| 73 fssqEn[n] += (*pp) * (*pp); | |
| 74 bssqEn[n] += sampEn_win[SUBL - l - 1] * (*pp) * (*pp); | |
| 75 pp++; | |
| 76 } | |
| 77 } | |
| 78 | |
| 79 /* Calculate back of last seqence */ | |
| 80 | |
| 81 n = iLBCenc_inst->nsub - 1; | |
| 82 pp = residual + n * SUBL; | |
| 83 for (l = 0; l < SUBL - 5; l++) { | |
| 84 bssqEn[n] += (*pp) * (*pp); | |
| 85 pp++; | |
| 86 } | |
| 87 for (l = SUBL - 5; l < SUBL; l++) { | |
| 88 bssqEn[n] += sampEn_win[SUBL - l - 1] * (*pp) * (*pp); | |
| 89 pp++; | |
| 90 } | |
| 91 | |
| 92 /* find the index to the weighted 80 sample with | |
| 93 most energy */ | |
| 94 | |
| 95 if (iLBCenc_inst->mode == 20) | |
| 96 l = 1; | |
| 97 else | |
| 98 l = 0; | |
| 99 | |
| 100 max_ssqEn = (fssqEn[0] + bssqEn[1]) * ssqEn_win[l]; | |
| 101 max_ssqEn_n = 1; | |
| 102 for (n = 2; n < iLBCenc_inst->nsub; n++) { | |
| 103 | |
| 104 | |
| 105 | |
| 106 | |
| 107 | |
| 108 | |
| 109 l++; | |
| 110 if ((fssqEn[n - 1] + bssqEn[n]) * ssqEn_win[l] > max_ssqEn) { | |
| 111 max_ssqEn = (fssqEn[n - 1] + bssqEn[n]) * ssqEn_win[l]; | |
| 112 max_ssqEn_n = n; | |
| 113 } | |
| 114 } | |
| 115 | |
| 116 return max_ssqEn_n; | |
| 117 } |