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2 /******************************************************************
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3
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4 iLBC Speech Coder ANSI-C Source Code
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5
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6 filter.h
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7
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8 Copyright (C) The Internet Society (2004).
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9 All Rights Reserved.
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10
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11 ******************************************************************/
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12
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13
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14
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15
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16
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17
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18 #ifndef __iLBC_FILTER_H
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19 #define __iLBC_FILTER_H
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20
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21 void AllPoleFilter(float *InOut, /* (i/o) on entrance InOut[-orderCoef] to
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22 InOut[-1] contain the state of the
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23 filter (delayed samples). InOut[0] to
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24 InOut[lengthInOut-1] contain the filter
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25 input, on en exit InOut[-orderCoef] to
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26 InOut[-1] is unchanged and InOut[0] to
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27 InOut[lengthInOut-1] contain filtered
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28 samples */
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29 float *Coef, /* (i) filter coefficients, Coef[0] is assumed
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30 to be 1.0 */
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31 int lengthInOut, /* (i) number of input/output samples */
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32 int orderCoef /* (i) number of filter coefficients */
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33 );
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34
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35 void AllZeroFilter(float *In, /* (i) In[0] to In[lengthInOut-1] contain
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36 filter input samples */
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37 float *Coef, /* (i) filter coefficients (Coef[0] is assumed
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38 to be 1.0) */
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39 int lengthInOut, /* (i) number of input/output samples */
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40 int orderCoef, /* (i) number of filter coefficients */
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41 float *Out /* (i/o) on entrance Out[-orderCoef] to Out[-1]
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42 contain the filter state, on exit Out[0]
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43 to Out[lengthInOut-1] contain filtered
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44 samples */
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45 );
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46
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47 void ZeroPoleFilter(float *In, /* (i) In[0] to In[lengthInOut-1] contain filter
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48 input samples In[-orderCoef] to In[-1]
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49 contain state of all-zero section */
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50 float *ZeroCoef, /* (i) filter coefficients for all-zero
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51 section (ZeroCoef[0] is assumed to
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52 be 1.0) */
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53 float *PoleCoef, /* (i) filter coefficients for all-pole section
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54 (ZeroCoef[0] is assumed to be 1.0) */
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55 int lengthInOut, /* (i) number of input/output samples */
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56 int orderCoef, /* (i) number of filter coefficients */
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57 float *Out /* (i/o) on entrance Out[-orderCoef] to Out[-1]
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58 contain state of all-pole section. On
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59 exit Out[0] to Out[lengthInOut-1]
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60 contain filtered samples */
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61 );
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62
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63
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64
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65
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66
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67
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68 void DownSample(float *In, /* (i) input samples */
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69 float *Coef, /* (i) filter coefficients */
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70 int lengthIn, /* (i) number of input samples */
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71 float *state, /* (i) filter state */
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72 float *Out /* (o) downsampled output */
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73 );
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74
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75 #endif
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