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ffmpeg / libavcodec / ra288.c @ 71160c55

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/*
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 * RealAudio 2.0 (28.8K)
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 * Copyright (c) 2003 the ffmpeg project
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 *
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 * This library is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2 of the License, or (at your option) any later version.
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 *
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 * This library is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with this library; if not, write to the Free Software
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 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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 */
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#include "avcodec.h"
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#include "ra288.h"
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typedef struct {
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        float        history[8];
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        float        output[40];
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        float        pr1[36];
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        float        pr2[10];
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        int        phase, phasep;
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        float st1a[111],st1b[37],st1[37];
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        float st2a[38],st2b[11],st2[11];
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        float sb[41];
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        float lhist[10];
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} Real288_internal;
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static int ra288_decode_init(AVCodecContext * avctx)
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{
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        Real288_internal *glob=avctx->priv_data;
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        memset(glob,0,sizeof(Real288_internal));
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        return 0;
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}
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static void prodsum(float *tgt, float *src, int len, int n);
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static void co(int n, int i, int j, float *in, float *out, float *st1, float *st2, const float *table);
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static int pred(float *in, float *tgt, int n);
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static void colmult(float *tgt, float *m1, const float *m2, int n);
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/* initial decode */
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static void unpack(unsigned short *tgt, unsigned char *src, unsigned int len)
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{
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  int x,y,z;
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  int n,temp;
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  int buffer[len];
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  for (x=0;x<len;tgt[x++]=0)
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    buffer[x]=9+(x&1);
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  for (x=y=z=0;x<len/*was 38*/;x++) {
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    n=buffer[y]-z;
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    temp=src[x];
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    if (n<8) temp&=255>>(8-n);
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    tgt[y]+=temp<<z;
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    if (n<=8) {
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      tgt[++y]+=src[x]>>n;
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      z=8-n;
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    } else z+=8;
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  }
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}
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static void update(Real288_internal *glob)
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{
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  int x,y;
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  float buffer1[40],temp1[37];
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  float buffer2[8],temp2[11];
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  for (x=0,y=glob->phasep+5;x<40;buffer1[x++]=glob->output[(y++)%40]);
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  co(36,40,35,buffer1,temp1,glob->st1a,glob->st1b,table1);
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  if (pred(temp1,glob->st1,36))
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    colmult(glob->pr1,glob->st1,table1a,36);
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  for (x=0,y=glob->phase+1;x<8;buffer2[x++]=glob->history[(y++)%8]);
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  co(10,8,20,buffer2,temp2,glob->st2a,glob->st2b,table2);
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  if (pred(temp2,glob->st2,10))
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    colmult(glob->pr2,glob->st2,table2a,10);
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}
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/* Decode and produce output */
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static void decode(Real288_internal *glob, unsigned int input)
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{
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  unsigned int x,y;
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  float f;
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  double sum,sumsum;
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  float *p1,*p2;
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  float buffer[5];
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  const float *table;
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  for (x=36;x--;glob->sb[x+5]=glob->sb[x]);
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  for (x=5;x--;) {
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    p1=glob->sb+x;p2=glob->pr1;
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    for (sum=0,y=36;y--;sum-=(*(++p1))*(*(p2++)));
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    glob->sb[x]=sum;
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  }
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  f=amptable[input&7];
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  table=codetable+(input>>3)*5;
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  /* convert log and do rms */
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  for (sum=32,x=10;x--;sum-=glob->pr2[x]*glob->lhist[x]);
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  if (sum<0) sum=0; else if (sum>60) sum=60;
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  sumsum=exp(sum*0.1151292546497)*f;        /* pow(10.0,sum/20)*f */
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  for (sum=0,x=5;x--;) { buffer[x]=table[x]*sumsum; sum+=buffer[x]*buffer[x]; }
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  if ((sum/=5)<1) sum=1;
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  /* shift and store */
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  for (x=10;--x;glob->lhist[x]=glob->lhist[x-1]);
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  *glob->lhist=glob->history[glob->phase]=10*log10(sum)-32;
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  for (x=1;x<5;x++) for (y=x;y--;buffer[x]-=glob->pr1[x-y-1]*buffer[y]);
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  /* output */
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  for (x=0;x<5;x++) {
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    f=glob->sb[4-x]+buffer[x];
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    if (f>4095) f=4095; else if (f<-4095) f=-4095;
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    glob->output[glob->phasep+x]=glob->sb[4-x]=f;
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  }
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}
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/* column multiply */
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static void colmult(float *tgt, float *m1, const float *m2, int n)
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{
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  while (n--)
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    *(tgt++)=(*(m1++))*(*(m2++));
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}
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static int pred(float *in, float *tgt, int n)
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{
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  int x,y;
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  float *p1,*p2;
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  double f0,f1,f2;
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  float temp;
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  if (in[n]==0) return 0;
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  if ((f0=*in)<=0) return 0;
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  for (x=1;;x++) {
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    if (n<x) return 1;
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    p1=in+x;
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    p2=tgt;
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    f1=*(p1--);
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    for (y=x;--y;f1+=(*(p1--))*(*(p2++)));
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    p1=tgt+x-1;
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    p2=tgt;
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    *(p1--)=f2=-f1/f0;
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    for (y=x>>1;y--;) {
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      temp=*p2+*p1*f2;
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      *(p1--)+=*p2*f2;
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      *(p2++)=temp;
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    }
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    if ((f0+=f1*f2)<0) return 0;
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  }
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}
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static void co(int n, int i, int j, float *in, float *out, float *st1, float *st2, const float *table)
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{
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  int a,b,c;
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  unsigned int x;
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  float *fp;
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  float buffer1[37];
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  float buffer2[37];
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  float work[111];
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  /* rotate and multiply */
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  c=(b=(a=n+i)+j)-i;
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  fp=st1+i;
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  for (x=0;x<b;x++) {
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    if (x==c) fp=in;
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    work[x]=*(table++)*(*(st1++)=*(fp++));
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  }
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  prodsum(buffer1,work+n,i,n);
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  prodsum(buffer2,work+a,j,n);
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  for (x=0;x<=n;x++) {
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    *st2=*st2*(0.5625)+buffer1[x];
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    out[x]=*(st2++)+buffer2[x];
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  }
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  *out*=1.00390625; /* to prevent clipping */
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}
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/* product sum (lsf) */
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static void prodsum(float *tgt, float *src, int len, int n)
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{
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  unsigned int x;
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  float *p1,*p2;
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  double sum;
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  while (n>=0)
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  {
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    p1=(p2=src)-n;
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    for (sum=0,x=len;x--;sum+=(*p1++)*(*p2++));
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    tgt[n--]=sum;
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  }
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}
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static void * decode_block(AVCodecContext * avctx, unsigned char *in, signed short int *out,unsigned len)
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{
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  int x,y;
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  Real288_internal *glob=avctx->priv_data;
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  unsigned short int buffer[len];
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  unpack(buffer,in,len);
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  for (x=0;x<32;x++)
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  {
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    glob->phasep=(glob->phase=x&7)*5;
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    decode(glob,buffer[x]);
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    for (y=0;y<5;*(out++)=8*glob->output[glob->phasep+(y++)]);
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    if (glob->phase==3) update(glob);
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  }
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  return out;
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}
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/* Decode a block (celp) */
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static int ra288_decode_frame(AVCodecContext * avctx,
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            void *data, int *data_size,
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            uint8_t * buf, int buf_size)
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{
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    void *datao;
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    if (buf_size < avctx->block_align)
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    {
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        av_log(avctx, AV_LOG_ERROR, "ffra288: Error! Input buffer is too small [%d<%d]\n",buf_size,avctx->block_align);
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        return 0;
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    }
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    datao = data;
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    data = decode_block(avctx, buf, (signed short *)data, avctx->block_align);
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    *data_size = (char *)data - (char *)datao;
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    return avctx->block_align;
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}
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AVCodec ra_288_decoder =
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{
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    "real_288",
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    CODEC_TYPE_AUDIO,
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    CODEC_ID_RA_288,
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    sizeof(Real288_internal),
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    ra288_decode_init,
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    NULL,
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    NULL,
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    ra288_decode_frame,
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};