tremor/synthesis.c

   1 /********************************************************************
   2  *                                                                  *
   3  * THIS FILE IS PART OF THE OggVorbis 'TREMOR' CODEC SOURCE CODE.   *
   4  *                                                                  *
   5  * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
   6  * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
   7  * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
   8  *                                                                  *
   9  * THE OggVorbis 'TREMOR' SOURCE CODE IS (C) COPYRIGHT 1994-2002    *
  10  * BY THE Xiph.Org FOUNDATION http://www.xiph.org/                  *
  11  *                                                                  *
  12  ********************************************************************
  13
  14  function: single-block PCM synthesis
  15  last mod: $Id$
  16
  17  ********************************************************************/
  18
  19 #include <stdio.h>
  20 #include "ogg.h"
  21 #include "ivorbiscodec.h"
  22 #include "codec_internal.h"
  23 #include "registry.h"
  24 #include "misc.h"
  25 #include "os.h"
  26 #include "block.h"
  27
  28 int vorbis_synthesis(vorbis_block *vb,ogg_packet *op){
  29   vorbis_dsp_state     *vd=vb->vd;
  30   backend_lookup_state *b=(backend_lookup_state *)vd->backend_state;
  31   vorbis_info          *vi=vd->vi;
  32   codec_setup_info     *ci=(codec_setup_info *)vi->codec_setup;
  33   oggpack_buffer       *opb=&vb->opb;
  34   int                   type,mode,i;
  35
  36   /* first things first.  Make sure decode is ready */
  37   _vorbis_block_ripcord(vb);
  38   oggpack_readinit(opb,op->packet,op->bytes);
  39
  40   /* Check the packet type */
  41   if(oggpack_read(opb,1)!=0){
  42     /* Oops.  This is not an audio data packet */
  43     return(OV_ENOTAUDIO);
  44   }
  45
  46   /* read our mode and pre/post windowsize */
  47   mode=oggpack_read(opb,b->modebits);
  48   if(mode==-1)return(OV_EBADPACKET);
  49
  50   vb->mode=mode;
  51   vb->W=ci->mode_param[mode]->blockflag;
  52   if(vb->W){
  53     vb->lW=oggpack_read(opb,1);
  54     vb->nW=oggpack_read(opb,1);
  55     if(vb->nW==-1)   return(OV_EBADPACKET);
  56   }else{
  57     vb->lW=0;
  58     vb->nW=0;
  59   }
  60
  61   /* more setup */
  62   vb->granulepos=op->granulepos;
  63   vb->sequence=op->packetno-3; /* first block is third packet */
  64   vb->eofflag=op->e_o_s;
  65
  66   /* alloc pcm passback storage */
  67   vb->pcmend=ci->blocksizes[vb->W];
  68   vb->pcm=(ogg_int32_t **)_vorbis_block_alloc(vb,sizeof(*vb->pcm)*vi->channels);
  69   for(i=0;i<vi->channels;i++)
  70     vb->pcm[i]=(ogg_int32_t *)_vorbis_block_alloc(vb,vb->pcmend*sizeof(*vb->pcm[i]));
  71
  72   /* unpack_header enforces range checking */
  73   type=ci->map_type[ci->mode_param[mode]->mapping];
  74
  75   return(_mapping_P[type]->inverse(vb,b->mode[mode]));
  76 }
  77
  78 long vorbis_packet_blocksize(vorbis_info *vi,ogg_packet *op){
  79   codec_setup_info     *ci=(codec_setup_info *)vi->codec_setup;
  80   oggpack_buffer       opb;
  81   int                  mode;
  82
  83   oggpack_readinit(&opb,op->packet,op->bytes);
  84
  85   /* Check the packet type */
  86   if(oggpack_read(&opb,1)!=0){
  87     /* Oops.  This is not an audio data packet */
  88     return(OV_ENOTAUDIO);
  89   }
  90
  91   {
  92     int modebits=0;
  93     int v=ci->modes;
  94     while(v>1){
  95       modebits++;
  96       v>>=1;
  97     }
  98
  99     /* read our mode and pre/post windowsize */
 100     mode=oggpack_read(&opb,modebits);
 101   }
 102   if(mode==-1)return(OV_EBADPACKET);
 103   return(ci->blocksizes[ci->mode_param[mode]->blockflag]);
 104 }
 105
 106