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292 lines
7.9 KiB
292 lines
7.9 KiB
/* Copyright (C) 2002 Jean-Marc Valin |
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File: filters.c |
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Various analysis/synthesis filters |
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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 "filters.h" |
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#include "stack_alloc.h" |
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#include <math.h> |
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void bw_lpc(float gamma, float *lpc_in, float *lpc_out, int order) |
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{ |
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int i; |
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float tmp=1; |
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for (i=0;i<order+1;i++) |
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{ |
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lpc_out[i] = tmp * lpc_in[i]; |
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tmp *= gamma; |
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} |
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} |
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#ifdef _USE_SSE |
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#include "filters_sse.h" |
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#else |
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void filter_mem2(float *x, float *num, float *den, float *y, int N, int ord, float *mem) |
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{ |
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int i,j; |
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float xi,yi; |
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for (i=0;i<N;i++) |
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{ |
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xi=x[i]; |
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y[i] = num[0]*xi + mem[0]; |
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yi=y[i]; |
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for (j=0;j<ord-1;j++) |
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{ |
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mem[j] = mem[j+1] + num[j+1]*xi - den[j+1]*yi; |
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} |
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mem[ord-1] = num[ord]*xi - den[ord]*yi; |
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} |
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} |
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void iir_mem2(float *x, float *den, float *y, int N, int ord, float *mem) |
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{ |
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int i,j; |
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for (i=0;i<N;i++) |
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{ |
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y[i] = x[i] + mem[0]; |
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for (j=0;j<ord-1;j++) |
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{ |
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mem[j] = mem[j+1] - den[j+1]*y[i]; |
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} |
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mem[ord-1] = - den[ord]*y[i]; |
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} |
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} |
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#endif |
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void fir_mem2(float *x, float *num, float *y, int N, int ord, float *mem) |
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{ |
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int i,j; |
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float xi; |
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for (i=0;i<N;i++) |
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{ |
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xi=x[i]; |
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y[i] = num[0]*xi + mem[0]; |
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for (j=0;j<ord-1;j++) |
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{ |
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mem[j] = mem[j+1] + num[j+1]*xi; |
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} |
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mem[ord-1] = num[ord]*xi; |
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} |
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} |
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void syn_percep_zero(float *xx, float *ak, float *awk1, float *awk2, float *y, int N, int ord, char *stack) |
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{ |
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int i; |
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float *mem = PUSH(stack,ord, float); |
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for (i=0;i<ord;i++) |
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mem[i]=0; |
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filter_mem2(xx, awk1, ak, y, N, ord, mem); |
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for (i=0;i<ord;i++) |
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mem[i]=0; |
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iir_mem2(y, awk2, y, N, ord, mem); |
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} |
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void residue_percep_zero(float *xx, float *ak, float *awk1, float *awk2, float *y, int N, int ord, char *stack) |
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{ |
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int i; |
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float *mem = PUSH(stack,ord, float); |
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for (i=0;i<ord;i++) |
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mem[i]=0; |
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filter_mem2(xx, ak, awk1, y, N, ord, mem); |
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for (i=0;i<ord;i++) |
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mem[i]=0; |
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fir_mem2(y, awk2, y, N, ord, mem); |
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} |
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void qmf_decomp(float *xx, float *aa, float *y1, float *y2, int N, int M, float *mem, char *stack) |
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{ |
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int i,j,k,M2; |
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float *a; |
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float *x; |
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float *x2; |
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a = PUSH(stack, M, float); |
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x = PUSH(stack, N+M-1, float); |
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x2=x+M-1; |
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M2=M>>1; |
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for (i=0;i<M;i++) |
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a[M-i-1]=aa[i]; |
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for (i=0;i<M-1;i++) |
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x[i]=mem[M-i-2]; |
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for (i=0;i<N;i++) |
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x[i+M-1]=xx[i]; |
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for (i=0,k=0;i<N;i+=2,k++) |
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{ |
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y1[k]=0; |
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y2[k]=0; |
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for (j=0;j<M2;j++) |
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{ |
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y1[k]+=a[j]*(x[i+j]+x2[i-j]); |
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y2[k]-=a[j]*(x[i+j]-x2[i-j]); |
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j++; |
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y1[k]+=a[j]*(x[i+j]+x2[i-j]); |
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y2[k]+=a[j]*(x[i+j]-x2[i-j]); |
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} |
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} |
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for (i=0;i<M-1;i++) |
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mem[i]=xx[N-i-1]; |
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} |
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/* By segher */ |
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void fir_mem_up(float *x, float *a, float *y, int N, int M, float *mem, char *stack) |
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/* assumptions: |
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all odd x[i] are zero -- well, actually they are left out of the array now |
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N and M are multiples of 4 */ |
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{ |
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int i, j; |
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float *xx=PUSH(stack, M+N-1, float); |
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for (i = 0; i < N/2; i++) |
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xx[2*i] = x[N/2-1-i]; |
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for (i = 0; i < M - 1; i += 2) |
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xx[N+i] = mem[i+1]; |
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for (i = 0; i < N; i += 4) { |
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float y0, y1, y2, y3; |
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float x0; |
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y0 = y1 = y2 = y3 = 0.f; |
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x0 = xx[N-4-i]; |
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for (j = 0; j < M; j += 4) { |
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float x1; |
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float a0, a1; |
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a0 = a[j]; |
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a1 = a[j+1]; |
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x1 = xx[N-2+j-i]; |
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y0 += a0 * x1; |
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y1 += a1 * x1; |
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y2 += a0 * x0; |
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y3 += a1 * x0; |
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a0 = a[j+2]; |
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a1 = a[j+3]; |
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x0 = xx[N+j-i]; |
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y0 += a0 * x0; |
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y1 += a1 * x0; |
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y2 += a0 * x1; |
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y3 += a1 * x1; |
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} |
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y[i] = y0; |
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y[i+1] = y1; |
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y[i+2] = y2; |
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y[i+3] = y3; |
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} |
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for (i = 0; i < M - 1; i += 2) |
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mem[i+1] = xx[i]; |
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} |
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void comp_filter_mem_init (CombFilterMem *mem) |
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{ |
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mem->last_pitch=0; |
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mem->last_pitch_gain[0]=mem->last_pitch_gain[1]=mem->last_pitch_gain[2]=0; |
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mem->smooth_gain=1; |
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} |
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void comb_filter( |
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float *exc, /*decoded excitation*/ |
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float *new_exc, /*enhanced excitation*/ |
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float *ak, /*LPC filter coefs*/ |
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int p, /*LPC order*/ |
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int nsf, /*sub-frame size*/ |
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int pitch, /*pitch period*/ |
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float *pitch_gain, /*pitch gain (3-tap)*/ |
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float comb_gain, /*gain of comb filter*/ |
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CombFilterMem *mem |
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) |
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{ |
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int i; |
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float exc_energy=0, new_exc_energy=0; |
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float gain; |
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float step; |
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float fact; |
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/*Compute excitation energy prior to enhancement*/ |
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for (i=0;i<nsf;i++) |
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exc_energy+=exc[i]*exc[i]; |
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/*Some gain adjustment is pitch is too high or if unvoiced*/ |
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{ |
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float g=0; |
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g = .5*fabs(pitch_gain[0]+pitch_gain[1]+pitch_gain[2] + |
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mem->last_pitch_gain[0] + mem->last_pitch_gain[1] + mem->last_pitch_gain[2]); |
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if (g>1.3) |
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comb_gain*=1.3/g; |
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if (g<.5) |
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comb_gain*=2*g; |
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} |
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step = 1.0/nsf; |
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fact=0; |
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/*Apply pitch comb-filter (filter out noise between pitch harmonics)*/ |
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for (i=0;i<nsf;i++) |
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{ |
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fact += step; |
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new_exc[i] = exc[i] + comb_gain * fact * ( |
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pitch_gain[0]*exc[i-pitch+1] + |
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pitch_gain[1]*exc[i-pitch] + |
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pitch_gain[2]*exc[i-pitch-1] |
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) |
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+ comb_gain * (1-fact) * ( |
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mem->last_pitch_gain[0]*exc[i-mem->last_pitch+1] + |
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mem->last_pitch_gain[1]*exc[i-mem->last_pitch] + |
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mem->last_pitch_gain[2]*exc[i-mem->last_pitch-1] |
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); |
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} |
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mem->last_pitch_gain[0] = pitch_gain[0]; |
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mem->last_pitch_gain[1] = pitch_gain[1]; |
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mem->last_pitch_gain[2] = pitch_gain[2]; |
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mem->last_pitch = pitch; |
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/*Gain after enhancement*/ |
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for (i=0;i<nsf;i++) |
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new_exc_energy+=new_exc[i]*new_exc[i]; |
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/*Compute scaling factor and normalize energy*/ |
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gain = sqrt(exc_energy)/sqrt(.1+new_exc_energy); |
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if (gain < .5) |
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gain=.5; |
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if (gain>1) |
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gain=1; |
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for (i=0;i<nsf;i++) |
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{ |
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mem->smooth_gain = .96*mem->smooth_gain + .04*gain; |
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new_exc[i] *= mem->smooth_gain; |
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} |
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}
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