117 lines
3.4 KiB
C
117 lines
3.4 KiB
C
/* 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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