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/********************************************************************
* *
* THIS FILE IS PART OF THE OggVorbis 'TREMOR' CODEC SOURCE CODE. *
* *
* USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS *
* GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
* IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. *
* *
* THE OggVorbis 'TREMOR' SOURCE CODE IS (C) COPYRIGHT 1994-2003 *
* BY THE Xiph.Org FOUNDATION http://www.xiph.org/ *
* *
********************************************************************
function: single-block PCM synthesis
last mod: $Id$
********************************************************************/
#include <stdio.h>
#include "ogg.h"
#include "ivorbiscodec.h"
#include "codec_internal.h"
#include "registry.h"
#include "misc.h"
#include "os.h"
static ogg_int32_t *ipcm_vect[CHANNELS] IBSS_ATTR;
int vorbis_synthesis(vorbis_block *vb,ogg_packet *op,int decodep)
ICODE_ATTR_TREMOR_NOT_MDCT;
int vorbis_synthesis(vorbis_block *vb,ogg_packet *op,int decodep){
vorbis_dsp_state *vd=vb->vd;
private_state *b=(private_state *)vd->backend_state;
vorbis_info *vi=vd->vi;
codec_setup_info *ci=(codec_setup_info *)vi->codec_setup;
oggpack_buffer *opb=&vb->opb;
int type,mode,i;
/* first things first. Make sure decode is ready */
_vorbis_block_ripcord(vb);
oggpack_readinit(opb,op->packet);
/* Check the packet type */
if(oggpack_read(opb,1)!=0){
/* Oops. This is not an audio data packet */
return(OV_ENOTAUDIO);
}
/* read our mode and pre/post windowsize */
mode=oggpack_read(opb,b->modebits);
if(mode==-1)return(OV_EBADPACKET);
vb->mode=mode;
vb->W=ci->mode_param[mode]->blockflag;
if(vb->W){
vb->lW=oggpack_read(opb,1);
vb->nW=oggpack_read(opb,1);
if(vb->nW==-1) return(OV_EBADPACKET);
}else{
vb->lW=0;
vb->nW=0;
}
/* more setup */
vb->granulepos=op->granulepos;
vb->sequence=op->packetno-3; /* first block is third packet */
vb->eofflag=op->e_o_s;
if(decodep && vi->channels<=CHANNELS)
{
vb->pcm = ipcm_vect;
/* set pcm end point */
vb->pcmend=ci->blocksizes[vb->W];
/* use statically allocated buffer */
if(vd->reset_pcmb || vb->pcm[0]==NULL)
{
/* one-time initialisation at codec start
NOT for every block synthesis start
allows us to flip between buffers once initialised
by simply flipping pointers */
for(i=0; i<vi->channels; i++)
vb->pcm[i] = &vd->first_pcm[i*ci->blocksizes[1]];
}
vd->reset_pcmb = false;
/* unpack_header enforces range checking */
type=ci->map_type[ci->mode_param[mode]->mapping];
return(_mapping_P[type]->inverse(vb,b->mode[mode]));
}else{
/* no pcm */
vb->pcmend=0;
vb->pcm=NULL;
return(0);
}
}
long vorbis_packet_blocksize(vorbis_info *vi,ogg_packet *op){
codec_setup_info *ci=(codec_setup_info *)vi->codec_setup;
oggpack_buffer opb;
int mode;
oggpack_readinit(&opb,op->packet);
/* Check the packet type */
if(oggpack_read(&opb,1)!=0){
/* Oops. This is not an audio data packet */
return(OV_ENOTAUDIO);
}
{
int modebits=0;
int v=ci->modes;
while(v>1){
modebits++;
v>>=1;
}
/* read our mode and pre/post windowsize */
mode=oggpack_read(&opb,modebits);
}
if(mode==-1)return(OV_EBADPACKET);
return(ci->blocksizes[ci->mode_param[mode]->blockflag]);
}
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