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Diffstat (limited to 'trunk/codecs/ilbc/filter.c')
| -rw-r--r-- | trunk/codecs/ilbc/filter.c | 168 |
1 files changed, 0 insertions, 168 deletions
diff --git a/trunk/codecs/ilbc/filter.c b/trunk/codecs/ilbc/filter.c deleted file mode 100644 index f4ba63386..000000000 --- a/trunk/codecs/ilbc/filter.c +++ /dev/null @@ -1,168 +0,0 @@ - -/****************************************************************** - - iLBC Speech Coder ANSI-C Source Code - - filter.c - - Copyright (C) The Internet Society (2004). - All Rights Reserved. - -******************************************************************/ - - - -#include "iLBC_define.h" -#include "filter.h" - -/*----------------------------------------------------------------* - * all-pole filter - *---------------------------------------------------------------*/ - -void AllPoleFilter( - float *InOut, /* (i/o) on entrance InOut[-orderCoef] to - InOut[-1] contain the state of the - filter (delayed samples). InOut[0] to - InOut[lengthInOut-1] contain the filter - input, on en exit InOut[-orderCoef] to - InOut[-1] is unchanged and InOut[0] to - InOut[lengthInOut-1] contain filtered - samples */ - float *Coef,/* (i) filter coefficients, Coef[0] is assumed - to be 1.0 */ - int lengthInOut,/* (i) number of input/output samples */ - int orderCoef /* (i) number of filter coefficients */ -){ - int n,k; - - for(n=0;n<lengthInOut;n++){ - for(k=1;k<=orderCoef;k++){ - *InOut -= Coef[k]*InOut[-k]; - } - InOut++; - } -} - -/*----------------------------------------------------------------* - * all-zero filter - *---------------------------------------------------------------*/ - -void AllZeroFilter( - float *In, /* (i) In[0] to In[lengthInOut-1] contain - filter input samples */ - float *Coef,/* (i) filter coefficients (Coef[0] is assumed - to be 1.0) */ - int lengthInOut,/* (i) number of input/output samples */ - int orderCoef, /* (i) number of filter coefficients */ - float *Out /* (i/o) on entrance Out[-orderCoef] to Out[-1] - contain the filter state, on exit Out[0] - to Out[lengthInOut-1] contain filtered - samples */ -){ - int n,k; - - for(n=0;n<lengthInOut;n++){ - *Out = Coef[0]*In[0]; - for(k=1;k<=orderCoef;k++){ - *Out += Coef[k]*In[-k]; - } - - - Out++; - In++; - } -} - -/*----------------------------------------------------------------* - * pole-zero filter - *---------------------------------------------------------------*/ - -void ZeroPoleFilter( - float *In, /* (i) In[0] to In[lengthInOut-1] contain - filter input samples In[-orderCoef] to - In[-1] contain state of all-zero - section */ - float *ZeroCoef,/* (i) filter coefficients for all-zero - section (ZeroCoef[0] is assumed to - be 1.0) */ - float *PoleCoef,/* (i) filter coefficients for all-pole section - (ZeroCoef[0] is assumed to be 1.0) */ - int lengthInOut,/* (i) number of input/output samples */ - int orderCoef, /* (i) number of filter coefficients */ - float *Out /* (i/o) on entrance Out[-orderCoef] to Out[-1] - contain state of all-pole section. On - exit Out[0] to Out[lengthInOut-1] - contain filtered samples */ -){ - AllZeroFilter(In,ZeroCoef,lengthInOut,orderCoef,Out); - AllPoleFilter(Out,PoleCoef,lengthInOut,orderCoef); -} - -/*----------------------------------------------------------------* - * downsample (LP filter and decimation) - *---------------------------------------------------------------*/ - -void DownSample ( - float *In, /* (i) input samples */ - float *Coef, /* (i) filter coefficients */ - int lengthIn, /* (i) number of input samples */ - float *state, /* (i) filter state */ - float *Out /* (o) downsampled output */ -){ - float o; - float *Out_ptr = Out; - float *Coef_ptr, *In_ptr; - float *state_ptr; - int i, j, stop; - - /* LP filter and decimate at the same time */ - - for (i = DELAY_DS; i < lengthIn; i+=FACTOR_DS) - { - Coef_ptr = &Coef[0]; - In_ptr = &In[i]; - state_ptr = &state[FILTERORDER_DS-2]; - - - - o = (float)0.0; - - stop = (i < FILTERORDER_DS) ? i + 1 : FILTERORDER_DS; - - for (j = 0; j < stop; j++) - { - o += *Coef_ptr++ * (*In_ptr--); - } - for (j = i + 1; j < FILTERORDER_DS; j++) - { - o += *Coef_ptr++ * (*state_ptr--); - } - - *Out_ptr++ = o; - } - - /* Get the last part (use zeros as input for the future) */ - - for (i=(lengthIn+FACTOR_DS); i<(lengthIn+DELAY_DS); - i+=FACTOR_DS) { - - o=(float)0.0; - - if (i<lengthIn) { - Coef_ptr = &Coef[0]; - In_ptr = &In[i]; - for (j=0; j<FILTERORDER_DS; j++) { - o += *Coef_ptr++ * (*Out_ptr--); - } - } else { - Coef_ptr = &Coef[i-lengthIn]; - In_ptr = &In[lengthIn-1]; - for (j=0; j<FILTERORDER_DS-(i-lengthIn); j++) { - o += *Coef_ptr++ * (*In_ptr--); - } - } - *Out_ptr++ = o; - } -} - - |