Mercurial > hg > audiostuff
comparison intercom/ilbc/StateConstructW.c @ 2:13be24d74cd2
import intercom-0.4.1
| author | Peter Meerwald <pmeerw@cosy.sbg.ac.at> |
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| 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 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(int idxForMax, /* (i) 6-bit index for the quantization of | |
| 25 max amplitude */ | |
| 26 int *idxVec, /* (i) vector of quantization indexes */ | |
| 27 float *syntDenum, /* (i) synthesis filter denumerator */ | |
| 28 float *out, /* (o) the decoded state vector */ | |
| 29 int len /* (i) length of a state vector */ | |
| 30 ) | |
| 31 { | |
| 32 float maxVal, tmpbuf[LPC_FILTERORDER + 2 * STATE_LEN], *tmp, | |
| 33 numerator[LPC_FILTERORDER + 1]; | |
| 34 float foutbuf[LPC_FILTERORDER + 2 * STATE_LEN], *fout; | |
| 35 int k, tmpi; | |
| 36 | |
| 37 /* decoding of the maximum value */ | |
| 38 | |
| 39 maxVal = state_frgqTbl[idxForMax]; | |
| 40 maxVal = (float) pow(10, maxVal) / (float) 4.5; | |
| 41 | |
| 42 /* initialization of buffers and coefficients */ | |
| 43 | |
| 44 memset(tmpbuf, 0, LPC_FILTERORDER * sizeof(float)); | |
| 45 memset(foutbuf, 0, LPC_FILTERORDER * sizeof(float)); | |
| 46 for (k = 0; k < LPC_FILTERORDER; k++) { | |
| 47 numerator[k] = syntDenum[LPC_FILTERORDER - k]; | |
| 48 } | |
| 49 numerator[LPC_FILTERORDER] = syntDenum[0]; | |
| 50 tmp = &tmpbuf[LPC_FILTERORDER]; | |
| 51 fout = &foutbuf[LPC_FILTERORDER]; | |
| 52 | |
| 53 /* decoding of the sample values */ | |
| 54 | |
| 55 for (k = 0; k < len; k++) { | |
| 56 tmpi = len - 1 - k; | |
| 57 /* maxVal = 1/scal */ | |
| 58 tmp[k] = maxVal * state_sq3Tbl[idxVec[tmpi]]; | |
| 59 } | |
| 60 | |
| 61 /* circular convolution with all-pass filter */ | |
| 62 | |
| 63 memset(tmp + len, 0, len * sizeof(float)); | |
| 64 ZeroPoleFilter(tmp, numerator, syntDenum, 2 * len, | |
| 65 LPC_FILTERORDER, fout); | |
| 66 for (k = 0; k < len; k++) { | |
| 67 out[k] = fout[len - 1 - k] + fout[2 * len - 1 - k]; | |
| 68 } | |
| 69 } |