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 1994-2003    *
  10  * BY THE Xiph.Org FOUNDATION http://www.xiph.org/                  *
  11  *                                                                  *
  12  ********************************************************************
  13
  14  function: single-block PCM synthesis
  15  last mod: $Id: synthesis.c,v 1.4 2003/03/29 03:07:21 xiphmont Exp $
  16
  17  ********************************************************************/
  18
  19 #include <stdio.h>
  20 #include <ogg/ogg.h>
  21 #include "ivorbiscodec.h"
  22 #include "codec_internal.h"
  23 #include "registry.h"
  24 #include "misc.h"
  25 #include "block.h"
  26
  27 static int _vorbis_synthesis1(vorbis_block *vb,ogg_packet *op,int decodep){
  28   vorbis_dsp_state     *vd= vb ? vb->vd : 0;
  29   private_state        *b= vd ? (private_state *)vd->backend_state: 0;
  30   vorbis_info          *vi= vd ? vd->vi : 0;
  31   codec_setup_info     *ci= vi ? (codec_setup_info *)vi->codec_setup : 0;
  32   oggpack_buffer       *opb=vb ? &vb->opb : 0;
  33   int                   type,mode,i;
  34
  35   if (!vd || !b || !vi || !ci || !opb) {
  36     return OV_EBADPACKET;
  37   }
  38
  39   /* first things first.  Make sure decode is ready */
  40   _vorbis_block_ripcord(vb);
  41   oggpack_readinit(opb,op->packet,op->bytes);
  42
  43   /* Check the packet type */
  44   if(oggpack_read(opb,1)!=0){
  45     /* Oops.  This is not an audio data packet */
  46     return(OV_ENOTAUDIO);
  47   }
  48
  49   /* read our mode and pre/post windowsize */
  50   mode=oggpack_read(opb,b->modebits);
  51   if(mode==-1)return(OV_EBADPACKET);
  52
  53   vb->mode=mode;
  54   if(!ci->mode_param[mode]){
  55     return(OV_EBADPACKET);
  56   }
  57
  58   vb->W=ci->mode_param[mode]->blockflag;
  59   if(vb->W){
  60     vb->lW=oggpack_read(opb,1);
  61     vb->nW=oggpack_read(opb,1);
  62     if(vb->nW==-1)   return(OV_EBADPACKET);
  63   }else{
  64     vb->lW=0;
  65     vb->nW=0;
  66   }
  67
  68   /* more setup */
  69   vb->granulepos=op->granulepos;
  70   vb->sequence=op->packetno; /* first block is third packet */
  71   vb->eofflag=op->e_o_s;
  72
  73   if(decodep){
  74     /* alloc pcm passback storage */
  75     vb->pcmend=ci->blocksizes[vb->W];
  76     vb->pcm=(ogg_int32_t **)_vorbis_block_alloc(vb,sizeof(*vb->pcm)*vi->channels);
  77     for(i=0;i<vi->channels;i++)
  78       vb->pcm[i]=(ogg_int32_t *)_vorbis_block_alloc(vb,vb->pcmend*sizeof(*vb->pcm[i]));
  79
  80     /* unpack_header enforces range checking */
  81     type=ci->map_type[ci->mode_param[mode]->mapping];
  82
  83     return(_mapping_P[type]->inverse(vb,b->mode[mode]));
  84   }else{
  85     /* no pcm */
  86     vb->pcmend=0;
  87     vb->pcm=NULL;
  88
  89     return(0);
  90   }
  91 }
  92
  93 int vorbis_synthesis(vorbis_block *vb,ogg_packet *op){
  94   return _vorbis_synthesis1(vb,op,1);
  95 }
  96
  97 /* used to track pcm position without actually performing decode.
  98    Useful for sequential 'fast forward' */
  99 int vorbis_synthesis_trackonly(vorbis_block *vb,ogg_packet *op){
 100   return _vorbis_synthesis1(vb,op,0);
 101 }
 102
 103 long vorbis_packet_blocksize(vorbis_info *vi,ogg_packet *op){
 104   codec_setup_info     *ci=(codec_setup_info *)vi->codec_setup;
 105   oggpack_buffer       opb;
 106   int                  mode;
 107
 108   oggpack_readinit(&opb,op->packet,op->bytes);
 109
 110   /* Check the packet type */
 111   if(oggpack_read(&opb,1)!=0){
 112     /* Oops.  This is not an audio data packet */
 113     return(OV_ENOTAUDIO);
 114   }
 115
 116   {
 117     int modebits=0;
 118     int v=ci->modes;
 119     while(v>1){
 120       modebits++;
 121       v>>=1;
 122     }
 123
 124     /* read our mode and pre/post windowsize */
 125     mode=oggpack_read(&opb,modebits);
 126   }
 127   if(mode==-1 || !ci->mode_param[mode])return(OV_EBADPACKET);
 128   return(ci->blocksizes[ci->mode_param[mode]->blockflag]);
 129 }
 130
 131