Mercurial > hg > audiostuff
comparison intercom/ilbc/hpInput.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 | |
| 7 | |
| 8 | |
| 9 | |
| 10 hpInput.c | |
| 11 | |
| 12 Copyright (C) The Internet Society (2004). | |
| 13 All Rights Reserved. | |
| 14 | |
| 15 ******************************************************************/ | |
| 16 | |
| 17 #include "constants.h" | |
| 18 | |
| 19 /*----------------------------------------------------------------* | |
| 20 * Input high-pass filter | |
| 21 *---------------------------------------------------------------*/ | |
| 22 | |
| 23 void hpInput(float *In, /* (i) vector to filter */ | |
| 24 int len, /* (i) length of vector to filter */ | |
| 25 float *Out, /* (o) the resulting filtered vector */ | |
| 26 float *mem /* (i/o) the filter state */ | |
| 27 ) | |
| 28 { | |
| 29 int i; | |
| 30 float *pi, *po; | |
| 31 | |
| 32 /* all-zero section */ | |
| 33 | |
| 34 pi = &In[0]; | |
| 35 po = &Out[0]; | |
| 36 for (i = 0; i < len; i++) { | |
| 37 *po = hpi_zero_coefsTbl[0] * (*pi); | |
| 38 *po += hpi_zero_coefsTbl[1] * mem[0]; | |
| 39 *po += hpi_zero_coefsTbl[2] * mem[1]; | |
| 40 | |
| 41 mem[1] = mem[0]; | |
| 42 mem[0] = *pi; | |
| 43 po++; | |
| 44 pi++; | |
| 45 | |
| 46 } | |
| 47 | |
| 48 /* all-pole section */ | |
| 49 | |
| 50 po = &Out[0]; | |
| 51 for (i = 0; i < len; i++) { | |
| 52 *po -= hpi_pole_coefsTbl[1] * mem[2]; | |
| 53 *po -= hpi_pole_coefsTbl[2] * mem[3]; | |
| 54 | |
| 55 mem[3] = mem[2]; | |
| 56 mem[2] = *po; | |
| 57 po++; | |
| 58 | |
| 59 | |
| 60 | |
| 61 | |
| 62 | |
| 63 } | |
| 64 } |