[16] | 1 | /******************************************************************** |
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| 2 | * * |
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| 3 | * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE. * |
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| 4 | * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS * |
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| 5 | * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE * |
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| 6 | * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. * |
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| 7 | * * |
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| 8 | * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2007 * |
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| 9 | * by the Xiph.Org Foundation http://www.xiph.org/ * |
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| 10 | * * |
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| 11 | ******************************************************************** |
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| 12 | |
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| 13 | function: single-block PCM synthesis |
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| 14 | last mod: $Id: synthesis.c 13293 2007-07-24 00:09:47Z xiphmont $ |
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| 15 | |
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| 16 | ********************************************************************/ |
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| 17 | |
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| 18 | #include <stdio.h> |
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| 19 | #include <ogg/ogg.h> |
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| 20 | #include "vorbis/codec.h" |
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| 21 | #include "codec_internal.h" |
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| 22 | #include "registry.h" |
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| 23 | #include "misc.h" |
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| 24 | #include "os.h" |
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| 25 | |
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| 26 | int vorbis_synthesis(vorbis_block *vb,ogg_packet *op){ |
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| 27 | vorbis_dsp_state *vd=vb->vd; |
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| 28 | private_state *b=vd->backend_state; |
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| 29 | vorbis_info *vi=vd->vi; |
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| 30 | codec_setup_info *ci=vi->codec_setup; |
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| 31 | oggpack_buffer *opb=&vb->opb; |
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| 32 | int type,mode,i; |
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| 33 | |
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| 34 | /* first things first. Make sure decode is ready */ |
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| 35 | _vorbis_block_ripcord(vb); |
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| 36 | oggpack_readinit(opb,op->packet,op->bytes); |
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| 37 | |
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| 38 | /* Check the packet type */ |
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| 39 | if(oggpack_read(opb,1)!=0){ |
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| 40 | /* Oops. This is not an audio data packet */ |
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| 41 | return(OV_ENOTAUDIO); |
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| 42 | } |
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| 43 | |
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| 44 | /* read our mode and pre/post windowsize */ |
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| 45 | mode=oggpack_read(opb,b->modebits); |
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| 46 | if(mode==-1)return(OV_EBADPACKET); |
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| 47 | |
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| 48 | vb->mode=mode; |
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| 49 | vb->W=ci->mode_param[mode]->blockflag; |
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| 50 | if(vb->W){ |
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| 51 | |
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| 52 | /* this doesn;t get mapped through mode selection as it's used |
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| 53 | only for window selection */ |
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| 54 | vb->lW=oggpack_read(opb,1); |
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| 55 | vb->nW=oggpack_read(opb,1); |
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| 56 | if(vb->nW==-1) return(OV_EBADPACKET); |
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| 57 | }else{ |
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| 58 | vb->lW=0; |
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| 59 | vb->nW=0; |
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| 60 | } |
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| 61 | |
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| 62 | /* more setup */ |
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| 63 | vb->granulepos=op->granulepos; |
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| 64 | vb->sequence=op->packetno; |
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| 65 | vb->eofflag=op->e_o_s; |
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| 66 | |
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| 67 | /* alloc pcm passback storage */ |
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| 68 | vb->pcmend=ci->blocksizes[vb->W]; |
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| 69 | vb->pcm=_vorbis_block_alloc(vb,sizeof(*vb->pcm)*vi->channels); |
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| 70 | for(i=0;i<vi->channels;i++) |
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| 71 | vb->pcm[i]=_vorbis_block_alloc(vb,vb->pcmend*sizeof(*vb->pcm[i])); |
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| 72 | |
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| 73 | /* unpack_header enforces range checking */ |
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| 74 | type=ci->map_type[ci->mode_param[mode]->mapping]; |
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| 75 | |
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| 76 | return(_mapping_P[type]->inverse(vb,ci->map_param[ci->mode_param[mode]-> |
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| 77 | mapping])); |
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| 78 | } |
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| 79 | |
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| 80 | /* used to track pcm position without actually performing decode. |
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| 81 | Useful for sequential 'fast forward' */ |
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| 82 | int vorbis_synthesis_trackonly(vorbis_block *vb,ogg_packet *op){ |
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| 83 | vorbis_dsp_state *vd=vb->vd; |
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| 84 | private_state *b=vd->backend_state; |
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| 85 | vorbis_info *vi=vd->vi; |
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| 86 | codec_setup_info *ci=vi->codec_setup; |
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| 87 | oggpack_buffer *opb=&vb->opb; |
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| 88 | int mode; |
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| 89 | |
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| 90 | /* first things first. Make sure decode is ready */ |
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| 91 | _vorbis_block_ripcord(vb); |
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| 92 | oggpack_readinit(opb,op->packet,op->bytes); |
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| 93 | |
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| 94 | /* Check the packet type */ |
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| 95 | if(oggpack_read(opb,1)!=0){ |
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| 96 | /* Oops. This is not an audio data packet */ |
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| 97 | return(OV_ENOTAUDIO); |
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| 98 | } |
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| 99 | |
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| 100 | /* read our mode and pre/post windowsize */ |
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| 101 | mode=oggpack_read(opb,b->modebits); |
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| 102 | if(mode==-1)return(OV_EBADPACKET); |
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| 103 | |
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| 104 | vb->mode=mode; |
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| 105 | vb->W=ci->mode_param[mode]->blockflag; |
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| 106 | if(vb->W){ |
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| 107 | vb->lW=oggpack_read(opb,1); |
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| 108 | vb->nW=oggpack_read(opb,1); |
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| 109 | if(vb->nW==-1) return(OV_EBADPACKET); |
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| 110 | }else{ |
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| 111 | vb->lW=0; |
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| 112 | vb->nW=0; |
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| 113 | } |
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| 114 | |
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| 115 | /* more setup */ |
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| 116 | vb->granulepos=op->granulepos; |
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| 117 | vb->sequence=op->packetno; |
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| 118 | vb->eofflag=op->e_o_s; |
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| 119 | |
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| 120 | /* no pcm */ |
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| 121 | vb->pcmend=0; |
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| 122 | vb->pcm=NULL; |
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| 123 | |
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| 124 | return(0); |
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| 125 | } |
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| 126 | |
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| 127 | long vorbis_packet_blocksize(vorbis_info *vi,ogg_packet *op){ |
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| 128 | codec_setup_info *ci=vi->codec_setup; |
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| 129 | oggpack_buffer opb; |
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| 130 | int mode; |
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| 131 | |
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| 132 | oggpack_readinit(&opb,op->packet,op->bytes); |
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| 133 | |
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| 134 | /* Check the packet type */ |
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| 135 | if(oggpack_read(&opb,1)!=0){ |
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| 136 | /* Oops. This is not an audio data packet */ |
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| 137 | return(OV_ENOTAUDIO); |
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| 138 | } |
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| 139 | |
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| 140 | { |
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| 141 | int modebits=0; |
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| 142 | int v=ci->modes; |
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| 143 | while(v>1){ |
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| 144 | modebits++; |
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| 145 | v>>=1; |
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| 146 | } |
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| 147 | |
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| 148 | /* read our mode and pre/post windowsize */ |
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| 149 | mode=oggpack_read(&opb,modebits); |
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| 150 | } |
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| 151 | if(mode==-1)return(OV_EBADPACKET); |
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| 152 | return(ci->blocksizes[ci->mode_param[mode]->blockflag]); |
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| 153 | } |
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| 154 | |
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| 155 | int vorbis_synthesis_halfrate(vorbis_info *vi,int flag){ |
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| 156 | /* set / clear half-sample-rate mode */ |
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| 157 | codec_setup_info *ci=vi->codec_setup; |
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| 158 | |
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| 159 | /* right now, our MDCT can't handle < 64 sample windows. */ |
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| 160 | if(ci->blocksizes[0]<=64 && flag)return -1; |
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| 161 | ci->halfrate_flag=(flag?1:0); |
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| 162 | return 0; |
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| 163 | } |
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| 164 | |
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| 165 | int vorbis_synthesis_halfrate_p(vorbis_info *vi){ |
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| 166 | codec_setup_info *ci=vi->codec_setup; |
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| 167 | return ci->halfrate_flag; |
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| 168 | } |
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| 169 | |
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| 170 | |
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