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 17027 2010-03-25 05:21:20Z xiphmont $
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 
vorbis_synthesis(vorbis_block * vb,ogg_packet * op)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' */
vorbis_synthesis_trackonly(vorbis_block * vb,ogg_packet * op)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   vb->W=ci->mode_param[mode]->blockflag;
118   if(vb->W){
119     vb->lW=oggpack_read(opb,1);
120     vb->nW=oggpack_read(opb,1);
121     if(vb->nW==-1)   return(OV_EBADPACKET);
122   }else{
123     vb->lW=0;
124     vb->nW=0;
125   }
126 
127   /* more setup */
128   vb->granulepos=op->granulepos;
129   vb->sequence=op->packetno;
130   vb->eofflag=op->e_o_s;
131 
132   /* no pcm */
133   vb->pcmend=0;
134   vb->pcm=NULL;
135 
136   return(0);
137 }
138 
vorbis_packet_blocksize(vorbis_info * vi,ogg_packet * op)139 long vorbis_packet_blocksize(vorbis_info *vi,ogg_packet *op){
140   codec_setup_info     *ci=vi->codec_setup;
141   oggpack_buffer       opb;
142   int                  mode;
143 
144   oggpack_readinit(&opb,op->packet,op->bytes);
145 
146   /* Check the packet type */
147   if(oggpack_read(&opb,1)!=0){
148     /* Oops.  This is not an audio data packet */
149     return(OV_ENOTAUDIO);
150   }
151 
152   {
153     int modebits=0;
154     int v=ci->modes;
155     while(v>1){
156       modebits++;
157       v>>=1;
158     }
159 
160     /* read our mode and pre/post windowsize */
161     mode=oggpack_read(&opb,modebits);
162   }
163   if(mode==-1)return(OV_EBADPACKET);
164   return(ci->blocksizes[ci->mode_param[mode]->blockflag]);
165 }
166 
vorbis_synthesis_halfrate(vorbis_info * vi,int flag)167 int vorbis_synthesis_halfrate(vorbis_info *vi,int flag){
168   /* set / clear half-sample-rate mode */
169   codec_setup_info     *ci=vi->codec_setup;
170 
171   /* right now, our MDCT can't handle < 64 sample windows. */
172   if(ci->blocksizes[0]<=64 && flag)return -1;
173   ci->halfrate_flag=(flag?1:0);
174   return 0;
175 }
176 
vorbis_synthesis_halfrate_p(vorbis_info * vi)177 int vorbis_synthesis_halfrate_p(vorbis_info *vi){
178   codec_setup_info     *ci=vi->codec_setup;
179   return ci->halfrate_flag;
180 }
181