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view libs/vorbis/synthesis.c @ 0:b2f14e535253

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author John Tsiombikas <nuclear@member.fsf.org>
date Sat, 01 Feb 2014 19:58:19 +0200
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1 /********************************************************************
2 * *
3 * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE. *
4 * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS *
5 * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
6 * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. *
7 * *
8 * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2009 *
9 * by the Xiph.Org Foundation http://www.xiph.org/ *
10 * *
11 ********************************************************************
12
13 function: single-block PCM synthesis
14 last mod: $Id: synthesis.c 17474 2010-09-30 03:41:41Z gmaxwell $
15
16 ********************************************************************/
17
18 #include <stdio.h>
19 #include <ogg/ogg.h>
20 #include "vorbis/codec.h"
21 #include "codec_internal.h"
22 #include "registry.h"
23 #include "misc.h"
24 #include "os.h"
25
26 int vorbis_synthesis(vorbis_block *vb,ogg_packet *op){
27 vorbis_dsp_state *vd= vb ? vb->vd : 0;
28 private_state *b= vd ? vd->backend_state : 0;
29 vorbis_info *vi= vd ? vd->vi : 0;
30 codec_setup_info *ci= vi ? vi->codec_setup : 0;
31 oggpack_buffer *opb=vb ? &vb->opb : 0;
32 int type,mode,i;
33
34 if (!vd || !b || !vi || !ci || !opb) {
35 return OV_EBADPACKET;
36 }
37
38 /* first things first. Make sure decode is ready */
39 _vorbis_block_ripcord(vb);
40 oggpack_readinit(opb,op->packet,op->bytes);
41
42 /* Check the packet type */
43 if(oggpack_read(opb,1)!=0){
44 /* Oops. This is not an audio data packet */
45 return(OV_ENOTAUDIO);
46 }
47
48 /* read our mode and pre/post windowsize */
49 mode=oggpack_read(opb,b->modebits);
50 if(mode==-1){
51 return(OV_EBADPACKET);
52 }
53
54 vb->mode=mode;
55 if(!ci->mode_param[mode]){
56 return(OV_EBADPACKET);
57 }
58
59 vb->W=ci->mode_param[mode]->blockflag;
60 if(vb->W){
61
62 /* this doesn;t get mapped through mode selection as it's used
63 only for window selection */
64 vb->lW=oggpack_read(opb,1);
65 vb->nW=oggpack_read(opb,1);
66 if(vb->nW==-1){
67 return(OV_EBADPACKET);
68 }
69 }else{
70 vb->lW=0;
71 vb->nW=0;
72 }
73
74 /* more setup */
75 vb->granulepos=op->granulepos;
76 vb->sequence=op->packetno;
77 vb->eofflag=op->e_o_s;
78
79 /* alloc pcm passback storage */
80 vb->pcmend=ci->blocksizes[vb->W];
81 vb->pcm=_vorbis_block_alloc(vb,sizeof(*vb->pcm)*vi->channels);
82 for(i=0;i<vi->channels;i++)
83 vb->pcm[i]=_vorbis_block_alloc(vb,vb->pcmend*sizeof(*vb->pcm[i]));
84
85 /* unpack_header enforces range checking */
86 type=ci->map_type[ci->mode_param[mode]->mapping];
87
88 return(_mapping_P[type]->inverse(vb,ci->map_param[ci->mode_param[mode]->
89 mapping]));
90 }
91
92 /* used to track pcm position without actually performing decode.
93 Useful for sequential 'fast forward' */
94 int vorbis_synthesis_trackonly(vorbis_block *vb,ogg_packet *op){
95 vorbis_dsp_state *vd=vb->vd;
96 private_state *b=vd->backend_state;
97 vorbis_info *vi=vd->vi;
98 codec_setup_info *ci=vi->codec_setup;
99 oggpack_buffer *opb=&vb->opb;
100 int mode;
101
102 /* first things first. Make sure decode is ready */
103 _vorbis_block_ripcord(vb);
104 oggpack_readinit(opb,op->packet,op->bytes);
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 /* read our mode and pre/post windowsize */
113 mode=oggpack_read(opb,b->modebits);
114 if(mode==-1)return(OV_EBADPACKET);
115
116 vb->mode=mode;
117 if(!ci->mode_param[mode]){
118 return(OV_EBADPACKET);
119 }
120
121 vb->W=ci->mode_param[mode]->blockflag;
122 if(vb->W){
123 vb->lW=oggpack_read(opb,1);
124 vb->nW=oggpack_read(opb,1);
125 if(vb->nW==-1) return(OV_EBADPACKET);
126 }else{
127 vb->lW=0;
128 vb->nW=0;
129 }
130
131 /* more setup */
132 vb->granulepos=op->granulepos;
133 vb->sequence=op->packetno;
134 vb->eofflag=op->e_o_s;
135
136 /* no pcm */
137 vb->pcmend=0;
138 vb->pcm=NULL;
139
140 return(0);
141 }
142
143 long vorbis_packet_blocksize(vorbis_info *vi,ogg_packet *op){
144 codec_setup_info *ci=vi->codec_setup;
145 oggpack_buffer opb;
146 int mode;
147
148 oggpack_readinit(&opb,op->packet,op->bytes);
149
150 /* Check the packet type */
151 if(oggpack_read(&opb,1)!=0){
152 /* Oops. This is not an audio data packet */
153 return(OV_ENOTAUDIO);
154 }
155
156 {
157 int modebits=0;
158 int v=ci->modes;
159 while(v>1){
160 modebits++;
161 v>>=1;
162 }
163
164 /* read our mode and pre/post windowsize */
165 mode=oggpack_read(&opb,modebits);
166 }
167 if(mode==-1)return(OV_EBADPACKET);
168 return(ci->blocksizes[ci->mode_param[mode]->blockflag]);
169 }
170
171 int vorbis_synthesis_halfrate(vorbis_info *vi,int flag){
172 /* set / clear half-sample-rate mode */
173 codec_setup_info *ci=vi->codec_setup;
174
175 /* right now, our MDCT can't handle < 64 sample windows. */
176 if(ci->blocksizes[0]<=64 && flag)return -1;
177 ci->halfrate_flag=(flag?1:0);
178 return 0;
179 }
180
181 int vorbis_synthesis_halfrate_p(vorbis_info *vi){
182 codec_setup_info *ci=vi->codec_setup;
183 return ci->halfrate_flag;
184 }