1 /********************************************************************
3 * THIS FILE IS PART OF THE OggVorbis 'TREMOR' CODEC SOURCE CODE. *
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. *
9 * THE OggVorbis 'TREMOR' SOURCE CODE IS (C) COPYRIGHT 1994-2002 *
10 * BY THE Xiph.Org FOUNDATION http://www.xiph.org/ *
12 ********************************************************************
14 function: single-block PCM synthesis
15 last mod: $Id: synthesis.c,v 1.2 2002/09/03 03:15:19 xiphmont Exp $
17 ********************************************************************/
21 #include "ivorbiscodec.h"
22 #include "codec_internal.h"
27 int vorbis_synthesis(vorbis_block *vb,ogg_packet *op){
28 vorbis_dsp_state *vd=vb->vd;
29 backend_lookup_state *b=(backend_lookup_state *)vd->backend_state;
30 vorbis_info *vi=vd->vi;
31 codec_setup_info *ci=(codec_setup_info *)vi->codec_setup;
32 oggpack_buffer *opb=&vb->opb;
35 /* first things first. Make sure decode is ready */
36 _vorbis_block_ripcord(vb);
37 oggpack_readinit(opb,op->packet,op->bytes);
39 /* Check the packet type */
40 if(oggpack_read(opb,1)!=0){
41 /* Oops. This is not an audio data packet */
45 /* read our mode and pre/post windowsize */
46 mode=oggpack_read(opb,b->modebits);
47 if(mode==-1)return(OV_EBADPACKET);
50 vb->W=ci->mode_param[mode]->blockflag;
52 vb->lW=oggpack_read(opb,1);
53 vb->nW=oggpack_read(opb,1);
54 if(vb->nW==-1) return(OV_EBADPACKET);
61 vb->granulepos=op->granulepos;
62 vb->sequence=op->packetno-3; /* first block is third packet */
63 vb->eofflag=op->e_o_s;
65 /* alloc pcm passback storage */
66 vb->pcmend=ci->blocksizes[vb->W];
67 vb->pcm=(ogg_int32_t **)_vorbis_block_alloc(vb,sizeof(*vb->pcm)*vi->channels);
68 for(i=0;i<vi->channels;i++)
69 vb->pcm[i]=(ogg_int32_t *)_vorbis_block_alloc(vb,vb->pcmend*sizeof(*vb->pcm[i]));
71 /* unpack_header enforces range checking */
72 type=ci->map_type[ci->mode_param[mode]->mapping];
74 return(_mapping_P[type]->inverse(vb,b->mode[mode]));
77 long vorbis_packet_blocksize(vorbis_info *vi,ogg_packet *op){
78 codec_setup_info *ci=(codec_setup_info *)vi->codec_setup;
82 oggpack_readinit(&opb,op->packet,op->bytes);
84 /* Check the packet type */
85 if(oggpack_read(&opb,1)!=0){
86 /* Oops. This is not an audio data packet */
98 /* read our mode and pre/post windowsize */
99 mode=oggpack_read(&opb,modebits);
101 if(mode==-1)return(OV_EBADPACKET);
102 return(ci->blocksizes[ci->mode_param[mode]->blockflag]);