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116 lines
3.6 KiB
116 lines
3.6 KiB
/* Copyright (C) 2002 Jean-Marc Valin |
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File: vq.c |
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Vector quantization |
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Redistribution and use in source and binary forms, with or without |
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modification, are permitted provided that the following conditions |
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are met: |
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- Redistributions of source code must retain the above copyright |
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notice, this list of conditions and the following disclaimer. |
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- Redistributions in binary form must reproduce the above copyright |
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notice, this list of conditions and the following disclaimer in the |
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documentation and/or other materials provided with the distribution. |
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- Neither the name of the Xiph.org Foundation nor the names of its |
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contributors may be used to endorse or promote products derived from |
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this software without specific prior written permission. |
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR |
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CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
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EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
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NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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*/ |
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#include "vq.h" |
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/*Finds the index of the entry in a codebook that best matches the input*/ |
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int vq_index(float *in, float *codebook, int len, int entries) |
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{ |
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int i,j; |
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float min_dist=0; |
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int best_index=0; |
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for (i=0;i<entries;i++) |
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{ |
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float dist=0; |
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for (j=0;j<len;j++) |
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{ |
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float tmp = in[j]-*codebook++; |
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dist += tmp*tmp; |
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} |
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if (i==0 || dist<min_dist) |
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{ |
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min_dist=dist; |
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best_index=i; |
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} |
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} |
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return best_index; |
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} |
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/*Finds the indices of the n-best entries in a codebook*/ |
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void vq_nbest(float *in, float *codebook, int len, int entries, float *E, int N, int *nbest, float *best_dist) |
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{ |
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int i,j,k,used; |
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used = 0; |
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for (i=0;i<entries;i++) |
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{ |
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float dist=.5*E[i]; |
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for (j=0;j<len;j++) |
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dist -= in[j]**codebook++; |
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if (i<N || dist<best_dist[N-1]) |
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{ |
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for (k=N-1; (k >= 1) && (k > used || dist < best_dist[k-1]); k--) |
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{ |
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best_dist[k]=best_dist[k-1]; |
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nbest[k] = nbest[k-1]; |
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} |
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best_dist[k]=dist; |
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nbest[k]=i; |
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used++; |
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} |
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} |
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} |
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/*Finds the indices of the n-best entries in a codebook with sign*/ |
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void vq_nbest_sign(float *in, float *codebook, int len, int entries, float *E, int N, int *nbest, float *best_dist) |
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{ |
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int i,j,k, sign, used; |
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used=0; |
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for (i=0;i<entries;i++) |
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{ |
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float dist=0; |
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for (j=0;j<len;j++) |
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dist -= in[j]**codebook++; |
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if (dist>0) |
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{ |
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sign=1; |
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dist=-dist; |
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} else |
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{ |
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sign=0; |
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} |
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dist += .5*E[i]; |
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if (i<N || dist<best_dist[N-1]) |
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{ |
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for (k=N-1; (k >= 1) && (k > used || dist < best_dist[k-1]); k--) |
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{ |
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best_dist[k]=best_dist[k-1]; |
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nbest[k] = nbest[k-1]; |
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} |
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best_dist[k]=dist; |
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nbest[k]=i; |
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used++; |
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if (sign) |
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nbest[k]+=entries; |
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} |
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} |
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}
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