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 int vorbis_synthesis(vorbis_block *vb,ogg_packet *op,int decodep)
  31     ICODE_ATTR_TREMOR_NOT_MDCT;
  32 int vorbis_synthesis(vorbis_block *vb,ogg_packet *op,int decodep){
  33   vorbis_dsp_state     *vd=vb->vd;
  34   private_state        *b=(private_state *)vd->backend_state;
  35   vorbis_info          *vi=vd->vi;
  36   codec_setup_info     *ci=(codec_setup_info *)vi->codec_setup;
  37   oggpack_buffer       *opb=&vb->opb;
  38   int                   type,mode,i;
  39
  40   /* first things first.  Make sure decode is ready */
  41   _vorbis_block_ripcord(vb);
  42   oggpack_readinit(opb,op->packet);
  43
  44   /* Check the packet type */
  45   if(oggpack_read(opb,1)!=0){
  46     /* Oops.  This is not an audio data packet */
  47     return(OV_ENOTAUDIO);
  48   }
  49
  50   /* read our mode and pre/post windowsize */
  51   mode=oggpack_read(opb,b->modebits);
  52   if(mode==-1)return(OV_EBADPACKET);
  53
  54   vb->mode=mode;
  55   vb->W=ci->mode_param[mode]->blockflag;
  56   if(vb->W){
  57     vb->lW=oggpack_read(opb,1);
  58     vb->nW=oggpack_read(opb,1);
  59     if(vb->nW==-1)   return(OV_EBADPACKET);
  60   }else{
  61     vb->lW=0;
  62     vb->nW=0;
  63   }
  64
  65   /* more setup */
  66   vb->granulepos=op->granulepos;
  67   vb->sequence=op->packetno-3; /* first block is third packet */
  68   vb->eofflag=op->e_o_s;
  69
  70   if(decodep && vi->channels<=CHANNELS){
  71     vb->pcm = ipcm_vect;
  72
  73     /* set pcm end point */
  74     vb->pcmend=ci->blocksizes[vb->W];
  75     /* use statically allocated buffer */
  76     if(vd->reset_pcmb || vb->pcm[0]==NULL)
  77     {
  78       /* one-time initialisation at codec start
  79          NOT for every block synthesis start
  80          allows us to flip between buffers once initialised
  81          by simply flipping pointers */
  82       for(i=0; i<vi->channels; i++)
  83         vb->pcm[i] = &vd->first_pcm[i*ci->blocksizes[1]];
  84     }
  85     vd->reset_pcmb = false;
  86
  87     /* unpack_header enforces range checking */
  88     type=ci->map_type[ci->mode_param[mode]->mapping];
  89     return(_mapping_P[type]->inverse(vb,b->mode[mode]));
  90   }else{
  91     /* no pcm */
  92     vb->pcmend=0;
  93     vb->pcm=NULL;
  94
  95     return(0);
  96   }
  97 }
  98
  99 long vorbis_packet_blocksize(vorbis_info *vi,ogg_packet *op){
 100   codec_setup_info     *ci=(codec_setup_info *)vi->codec_setup;
 101   oggpack_buffer       opb;
 102   int                  mode;
 103
 104   oggpack_readinit(&opb,op->packet);
 105
 106   /* Check the packet type */
 107   if(oggpack_read(&opb,1)!=0){
 108     /* Oops.  This is not an audio data packet */
 109     return(OV_ENOTAUDIO);
 110   }
 111
 112   {
 113     int modebits=0;
 114     int v=ci->modes;
 115     while(v>1){
 116       modebits++;
 117       v>>=1;
 118     }
 119
 120     /* read our mode and pre/post windowsize */
 121     mode=oggpack_read(&opb,modebits);
 122   }
 123   if(mode==-1)return(OV_EBADPACKET);
 124   return(ci->blocksizes[ci->mode_param[mode]->blockflag]);
 125 }
 126
 127