Tristan Matthews | 0a329cc | 2013-07-17 13:20:14 -0400 | [diff] [blame] | 1 | |
| 2 | /****************************************************************** |
| 3 | |
| 4 | iLBC Speech Coder ANSI-C Source Code |
| 5 | |
| 6 | StateConstructW.c |
| 7 | |
| 8 | Copyright (C) The Internet Society (2004). |
| 9 | All Rights Reserved. |
| 10 | |
| 11 | ******************************************************************/ |
| 12 | |
| 13 | #include <math.h> |
| 14 | #include <string.h> |
| 15 | |
| 16 | #include "iLBC_define.h" |
| 17 | #include "constants.h" |
| 18 | #include "filter.h" |
| 19 | |
| 20 | /*----------------------------------------------------------------* |
| 21 | * decoding of the start state |
| 22 | *---------------------------------------------------------------*/ |
| 23 | |
| 24 | void StateConstructW( |
| 25 | int idxForMax, /* (i) 6-bit index for the quantization of |
| 26 | max amplitude */ |
| 27 | int *idxVec, /* (i) vector of quantization indexes */ |
| 28 | float *syntDenum, /* (i) synthesis filter denumerator */ |
| 29 | |
| 30 | |
| 31 | |
| 32 | |
| 33 | |
| 34 | float *out, /* (o) the decoded state vector */ |
| 35 | int len /* (i) length of a state vector */ |
| 36 | ){ |
| 37 | float maxVal, tmpbuf[LPC_FILTERORDER+2*STATE_LEN], *tmp, |
| 38 | numerator[LPC_FILTERORDER+1]; |
| 39 | float foutbuf[LPC_FILTERORDER+2*STATE_LEN], *fout; |
| 40 | int k,tmpi; |
| 41 | |
| 42 | /* decoding of the maximum value */ |
| 43 | |
| 44 | maxVal = state_frgqTbl[idxForMax]; |
| 45 | maxVal = (float)pow(10,maxVal)/(float)4.5; |
| 46 | |
| 47 | /* initialization of buffers and coefficients */ |
| 48 | |
| 49 | memset(tmpbuf, 0, LPC_FILTERORDER*sizeof(float)); |
| 50 | memset(foutbuf, 0, LPC_FILTERORDER*sizeof(float)); |
| 51 | for (k=0; k<LPC_FILTERORDER; k++) { |
| 52 | numerator[k]=syntDenum[LPC_FILTERORDER-k]; |
| 53 | } |
| 54 | numerator[LPC_FILTERORDER]=syntDenum[0]; |
| 55 | tmp = &tmpbuf[LPC_FILTERORDER]; |
| 56 | fout = &foutbuf[LPC_FILTERORDER]; |
| 57 | |
| 58 | /* decoding of the sample values */ |
| 59 | |
| 60 | for (k=0; k<len; k++) { |
| 61 | tmpi = len-1-k; |
| 62 | /* maxVal = 1/scal */ |
| 63 | tmp[k] = maxVal*state_sq3Tbl[idxVec[tmpi]]; |
| 64 | } |
| 65 | |
| 66 | /* circular convolution with all-pass filter */ |
| 67 | |
| 68 | memset(tmp+len, 0, len*sizeof(float)); |
| 69 | ZeroPoleFilter(tmp, numerator, syntDenum, 2*len, |
| 70 | LPC_FILTERORDER, fout); |
| 71 | for (k=0;k<len;k++) { |
| 72 | out[k] = fout[len-1-k]+fout[2*len-1-k]; |
| 73 | } |
| 74 | } |
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