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Diffstat (limited to 'trunk/codecs/ilbc/createCB.c')
| -rw-r--r-- | trunk/codecs/ilbc/createCB.c | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/trunk/codecs/ilbc/createCB.c b/trunk/codecs/ilbc/createCB.c new file mode 100644 index 000000000..a7efd9380 --- /dev/null +++ b/trunk/codecs/ilbc/createCB.c @@ -0,0 +1,216 @@ + + + +/****************************************************************** + + iLBC Speech Coder ANSI-C Source Code + + createCB.c + + Copyright (C) The Internet Society (2004). + All Rights Reserved. + +******************************************************************/ + +#include "iLBC_define.h" +#include "createCB.h" +#include "constants.h" +#include <string.h> +#include <math.h> + +/*----------------------------------------------------------------* + * Construct an additional codebook vector by filtering the + * initial codebook buffer. This vector is then used to expand + * the codebook with an additional section. + *---------------------------------------------------------------*/ + +void filteredCBvecs( + float *cbvectors, /* (o) Codebook vectors for the + higher section */ + float *mem, /* (i) Buffer to create codebook + vector from */ + int lMem /* (i) Length of buffer */ +){ + int j, k; + float *pp, *pp1; + float tempbuff2[CB_MEML+CB_FILTERLEN]; + float *pos; + + memset(tempbuff2, 0, (CB_HALFFILTERLEN-1)*sizeof(float)); + memcpy(&tempbuff2[CB_HALFFILTERLEN-1], mem, lMem*sizeof(float)); + memset(&tempbuff2[lMem+CB_HALFFILTERLEN-1], 0, + (CB_HALFFILTERLEN+1)*sizeof(float)); + + /* Create codebook vector for higher section by filtering */ + + /* do filtering */ + pos=cbvectors; + memset(pos, 0, lMem*sizeof(float)); + for (k=0; k<lMem; k++) { + pp=&tempbuff2[k]; + pp1=&cbfiltersTbl[CB_FILTERLEN-1]; + for (j=0;j<CB_FILTERLEN;j++) { + (*pos)+=(*pp++)*(*pp1--); + } + pos++; + } +} + + + +/*----------------------------------------------------------------* + * Search the augmented part of the codebook to find the best + * measure. + *----------------------------------------------------------------*/ + +void searchAugmentedCB( + int low, /* (i) Start index for the search */ + int high, /* (i) End index for the search */ + int stage, /* (i) Current stage */ + int startIndex, /* (i) Codebook index for the first + aug vector */ + float *target, /* (i) Target vector for encoding */ + float *buffer, /* (i) Pointer to the end of the buffer for + augmented codebook construction */ + float *max_measure, /* (i/o) Currently maximum measure */ + int *best_index,/* (o) Currently the best index */ + float *gain, /* (o) Currently the best gain */ + float *energy, /* (o) Energy of augmented codebook + vectors */ + float *invenergy/* (o) Inv energy of augmented codebook + vectors */ +) { + int icount, ilow, j, tmpIndex; + float *pp, *ppo, *ppi, *ppe, crossDot, alfa; + float weighted, measure, nrjRecursive; + float ftmp; + + /* Compute the energy for the first (low-5) + noninterpolated samples */ + nrjRecursive = (float) 0.0; + pp = buffer - low + 1; + for (j=0; j<(low-5); j++) { + nrjRecursive += ( (*pp)*(*pp) ); + pp++; + } + ppe = buffer - low; + + + for (icount=low; icount<=high; icount++) { + + /* Index of the codebook vector used for retrieving + energy values */ + tmpIndex = startIndex+icount-20; + + ilow = icount-4; + + /* Update the energy recursively to save complexity */ + nrjRecursive = nrjRecursive + (*ppe)*(*ppe); + ppe--; + energy[tmpIndex] = nrjRecursive; + + /* Compute cross dot product for the first (low-5) + samples */ + crossDot = (float) 0.0; + + + pp = buffer-icount; + for (j=0; j<ilow; j++) { + crossDot += target[j]*(*pp++); + } + + /* interpolation */ + alfa = (float) 0.2; + ppo = buffer-4; + ppi = buffer-icount-4; + for (j=ilow; j<icount; j++) { + weighted = ((float)1.0-alfa)*(*ppo)+alfa*(*ppi); + ppo++; + ppi++; + energy[tmpIndex] += weighted*weighted; + crossDot += target[j]*weighted; + alfa += (float)0.2; + } + + /* Compute energy and cross dot product for the + remaining samples */ + pp = buffer - icount; + for (j=icount; j<SUBL; j++) { + energy[tmpIndex] += (*pp)*(*pp); + crossDot += target[j]*(*pp++); + } + + if (energy[tmpIndex]>0.0) { + invenergy[tmpIndex]=(float)1.0/(energy[tmpIndex]+EPS); + } else { + invenergy[tmpIndex] = (float) 0.0; + } + + if (stage==0) { + measure = (float)-10000000.0; + + if (crossDot > 0.0) { + measure = crossDot*crossDot*invenergy[tmpIndex]; + } + } + else { + measure = crossDot*crossDot*invenergy[tmpIndex]; + } + + /* check if measure is better */ + ftmp = crossDot*invenergy[tmpIndex]; + + if ((measure>*max_measure) && (fabs(ftmp)<CB_MAXGAIN)) { + *best_index = tmpIndex; + *max_measure = measure; + *gain = ftmp; + } + } +} + + + + +/*----------------------------------------------------------------* + * Recreate a specific codebook vector from the augmented part. + * + *----------------------------------------------------------------*/ + +void createAugmentedVec( + int index, /* (i) Index for the augmented vector + to be created */ + float *buffer, /* (i) Pointer to the end of the buffer for + augmented codebook construction */ + float *cbVec/* (o) The construced codebook vector */ +) { + int ilow, j; + float *pp, *ppo, *ppi, alfa, alfa1, weighted; + + ilow = index-5; + + /* copy the first noninterpolated part */ + + pp = buffer-index; + memcpy(cbVec,pp,sizeof(float)*index); + + /* interpolation */ + + alfa1 = (float)0.2; + alfa = 0.0; + ppo = buffer-5; + ppi = buffer-index-5; + for (j=ilow; j<index; j++) { + weighted = ((float)1.0-alfa)*(*ppo)+alfa*(*ppi); + ppo++; + ppi++; + cbVec[j] = weighted; + alfa += alfa1; + } + + /* copy the second noninterpolated part */ + + pp = buffer - index; + memcpy(cbVec+index,pp,sizeof(float)*(SUBL-index)); +} + + |