apps/codecs/libtremor/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: $Id$
  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
  27
  28 static ogg_int32_t *ipcm_vect[CHANNELS] IBSS_ATTR;
  29
  30 static inline int _vorbis_synthesis1(vorbis_block *vb,ogg_packet *op,int decodep){
  31   vorbis_dsp_state     *vd= vb ? vb->vd : 0;
  32   private_state        *b= vd ? (private_state *)vd->backend_state: 0;
  33   vorbis_info          *vi= vd ? vd->vi : 0;
  34   codec_setup_info     *ci= vi ? (codec_setup_info *)vi->codec_setup : 0;
  35   oggpack_buffer       *opb=vb ? &vb->opb : 0;
  36   int                   type,mode,i;
  37
  38   if (!vd || !b || !vi || !ci || !opb) {
  39     return OV_EBADPACKET;
  40   }
  41
  42   /* first things first.  Make sure decode is ready */
  43   _vorbis_block_ripcord(vb);
  44   oggpack_readinit(opb,op->packet,op->bytes);
  45
  46   /* Check the packet type */
  47   if(oggpack_read(opb,1)!=0){
  48     /* Oops.  This is not an audio data packet */
  49     return(OV_ENOTAUDIO);
  50   }
  51
  52   /* read our mode and pre/post windowsize */
  53   mode=oggpack_read(opb,b->modebits);
  54   if(mode==-1)return(OV_EBADPACKET);
  55
  56   vb->mode=mode;
  57   if(!ci->mode_param[mode]){
  58     return(OV_EBADPACKET);
  59   }
  60
  61   vb->W=ci->mode_param[mode]->blockflag;
  62   if(vb->W){
  63     vb->lW=oggpack_read(opb,1);
  64     vb->nW=oggpack_read(opb,1);
  65     if(vb->nW==-1)   return(OV_EBADPACKET);
  66   }else{
  67     vb->lW=0;
  68     vb->nW=0;
  69   }
  70
  71   /* more setup */
  72   vb->granulepos=op->granulepos;
  73   vb->sequence=op->packetno-3; /* first block is third packet */
  74   vb->eofflag=op->e_o_s;
  75
  76   if(decodep && vi->channels<=CHANNELS)
  77   {
  78     vb->pcm = ipcm_vect;
  79
  80     /* set pcm end point */
  81     vb->pcmend=ci->blocksizes[vb->W];
  82     /* use statically allocated buffer */
  83     if(vd->reset_pcmb || vb->pcm[0]==NULL)
  84     {
  85       /* one-time initialisation at codec start
  86          NOT for every block synthesis start
  87          allows us to flip between buffers once initialised
  88          by simply flipping pointers */
  89       for(i=0; i<vi->channels; i++)
  90         vb->pcm[i] = &vd->first_pcm[i*ci->blocksizes[1]];
  91
  92     }
  93     vd->reset_pcmb = false;
  94
  95     /* unpack_header enforces range checking */
  96     type=ci->map_type[ci->mode_param[mode]->mapping];
  97     return(_mapping_P[type]->inverse(vb,b->mode[mode]));
  98   }else{
  99     /* no pcm */
 100     vb->pcmend=0;
 101     vb->pcm=NULL;
 102
 103     return(0);
 104   }
 105 }
 106
 107 int vorbis_synthesis(vorbis_block *vb,ogg_packet *op)
 108   ICODE_ATTR_TREMOR_NOT_MDCT;
 109 int vorbis_synthesis(vorbis_block *vb,ogg_packet *op){
 110   return _vorbis_synthesis1(vb,op,1);
 111 }
 112
 113 /* used to track pcm position without actually performing decode.
 114    Useful for sequential 'fast forward' */
 115 int vorbis_synthesis_trackonly(vorbis_block *vb,ogg_packet *op){
 116   return _vorbis_synthesis1(vb,op,0);
 117 }
 118
 119 long vorbis_packet_blocksize(vorbis_info *vi,ogg_packet *op){
 120   codec_setup_info     *ci=(codec_setup_info *)vi->codec_setup;
 121   oggpack_buffer       opb;
 122   int                  mode;
 123
 124   oggpack_readinit(&opb,op->packet,op->bytes);
 125
 126   /* Check the packet type */
 127   if(oggpack_read(&opb,1)!=0){
 128     /* Oops.  This is not an audio data packet */
 129     return(OV_ENOTAUDIO);
 130   }
 131
 132   {
 133     int modebits=0;
 134     int v=ci->modes;
 135     while(v>1){
 136       modebits++;
 137       v>>=1;
 138     }
 139
 140     /* read our mode and pre/post windowsize */
 141     mode=oggpack_read(&opb,modebits);
 142   }
 143   if(mode==-1)return(OV_EBADPACKET);
 144   return(ci->blocksizes[ci->mode_param[mode]->blockflag]);
 145 }
 146
 147