release/src/router/libvorbis/lib/synthesis.c

   1 /********************************************************************
   2  *                                                                  *
   3  * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
   4  * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
   5  * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
   6  * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
   7  *                                                                  *
   8  * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2009             *
   9  * by the Xiph.Org Foundation http://www.xiph.org/                  *
  10  *                                                                  *
  11  ********************************************************************
  12
  13  function: single-block PCM synthesis
  14  last mod: $Id: synthesis.c 16227 2009-07-08 06:58:46Z xiphmont $
  15
  16  ********************************************************************/
  17
  18 #include <stdio.h>
  19 #include <ogg/ogg.h>
  20 #include "vorbis/codec.h"
  21 #include "codec_internal.h"
  22 #include "registry.h"
  23 #include "misc.h"
  24 #include "os.h"
  25
  26 int vorbis_synthesis(vorbis_block *vb,ogg_packet *op){
  27   vorbis_dsp_state     *vd=vb->vd;
  28   private_state        *b=vd->backend_state;
  29   vorbis_info          *vi=vd->vi;
  30   codec_setup_info     *ci=vi->codec_setup;
  31   oggpack_buffer       *opb=&vb->opb;
  32   int                   type,mode,i;
  33
  34   /* first things first.  Make sure decode is ready */
  35   _vorbis_block_ripcord(vb);
  36   oggpack_readinit(opb,op->packet,op->bytes);
  37
  38   /* Check the packet type */
  39   if(oggpack_read(opb,1)!=0){
  40     /* Oops.  This is not an audio data packet */
  41     return(OV_ENOTAUDIO);
  42   }
  43
  44   /* read our mode and pre/post windowsize */
  45   mode=oggpack_read(opb,b->modebits);
  46   if(mode==-1)return(OV_EBADPACKET);
  47
  48   vb->mode=mode;
  49   vb->W=ci->mode_param[mode]->blockflag;
  50   if(vb->W){
  51
  52     /* this doesn;t get mapped through mode selection as it's used
  53        only for window selection */
  54     vb->lW=oggpack_read(opb,1);
  55     vb->nW=oggpack_read(opb,1);
  56     if(vb->nW==-1)   return(OV_EBADPACKET);
  57   }else{
  58     vb->lW=0;
  59     vb->nW=0;
  60   }
  61
  62   /* more setup */
  63   vb->granulepos=op->granulepos;
  64   vb->sequence=op->packetno;
  65   vb->eofflag=op->e_o_s;
  66
  67   /* alloc pcm passback storage */
  68   vb->pcmend=ci->blocksizes[vb->W];
  69   vb->pcm=_vorbis_block_alloc(vb,sizeof(*vb->pcm)*vi->channels);
  70   for(i=0;i<vi->channels;i++)
  71     vb->pcm[i]=_vorbis_block_alloc(vb,vb->pcmend*sizeof(*vb->pcm[i]));
  72
  73   /* unpack_header enforces range checking */
  74   type=ci->map_type[ci->mode_param[mode]->mapping];
  75
  76   return(_mapping_P[type]->inverse(vb,ci->map_param[ci->mode_param[mode]->
  77                                                    mapping]));
  78 }
  79
  80 /* used to track pcm position without actually performing decode.
  81    Useful for sequential 'fast forward' */
  82 int vorbis_synthesis_trackonly(vorbis_block *vb,ogg_packet *op){
  83   vorbis_dsp_state     *vd=vb->vd;
  84   private_state        *b=vd->backend_state;
  85   vorbis_info          *vi=vd->vi;
  86   codec_setup_info     *ci=vi->codec_setup;
  87   oggpack_buffer       *opb=&vb->opb;
  88   int                   mode;
  89
  90   /* first things first.  Make sure decode is ready */
  91   _vorbis_block_ripcord(vb);
  92   oggpack_readinit(opb,op->packet,op->bytes);
  93
  94   /* Check the packet type */
  95   if(oggpack_read(opb,1)!=0){
  96     /* Oops.  This is not an audio data packet */
  97     return(OV_ENOTAUDIO);
  98   }
  99
 100   /* read our mode and pre/post windowsize */
 101   mode=oggpack_read(opb,b->modebits);
 102   if(mode==-1)return(OV_EBADPACKET);
 103
 104   vb->mode=mode;
 105   vb->W=ci->mode_param[mode]->blockflag;
 106   if(vb->W){
 107     vb->lW=oggpack_read(opb,1);
 108     vb->nW=oggpack_read(opb,1);
 109     if(vb->nW==-1)   return(OV_EBADPACKET);
 110   }else{
 111     vb->lW=0;
 112     vb->nW=0;
 113   }
 114
 115   /* more setup */
 116   vb->granulepos=op->granulepos;
 117   vb->sequence=op->packetno;
 118   vb->eofflag=op->e_o_s;
 119
 120   /* no pcm */
 121   vb->pcmend=0;
 122   vb->pcm=NULL;
 123
 124   return(0);
 125 }
 126
 127 long vorbis_packet_blocksize(vorbis_info *vi,ogg_packet *op){
 128   codec_setup_info     *ci=vi->codec_setup;
 129   oggpack_buffer       opb;
 130   int                  mode;
 131
 132   oggpack_readinit(&opb,op->packet,op->bytes);
 133
 134   /* Check the packet type */
 135   if(oggpack_read(&opb,1)!=0){
 136     /* Oops.  This is not an audio data packet */
 137     return(OV_ENOTAUDIO);
 138   }
 139
 140   {
 141     int modebits=0;
 142     int v=ci->modes;
 143     while(v>1){
 144       modebits++;
 145       v>>=1;
 146     }
 147
 148     /* read our mode and pre/post windowsize */
 149     mode=oggpack_read(&opb,modebits);
 150   }
 151   if(mode==-1)return(OV_EBADPACKET);
 152   return(ci->blocksizes[ci->mode_param[mode]->blockflag]);
 153 }
 154
 155 int vorbis_synthesis_halfrate(vorbis_info *vi,int flag){
 156   /* set / clear half-sample-rate mode */
 157   codec_setup_info     *ci=vi->codec_setup;
 158
 159   /* right now, our MDCT can't handle < 64 sample windows. */
 160   if(ci->blocksizes[0]<=64 && flag)return -1;
 161   ci->halfrate_flag=(flag?1:0);
 162   return 0;
 163 }
 164
 165 int vorbis_synthesis_halfrate_p(vorbis_info *vi){
 166   codec_setup_info     *ci=vi->codec_setup;
 167   return ci->halfrate_flag;
 168 }