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: simple example decoder
14 last mod: $Id: decoder_example.c 16243 2009-07-10 02:49:31Z xiphmont $
15
16 ********************************************************************/
17
18/* Takes a vorbis bitstream from stdin and writes raw stereo PCM to
19   stdout. Decodes simple and chained OggVorbis files from beginning
20   to end. Vorbisfile.a is somewhat more complex than the code below.  */
21
22/* Note that this is POSIX, not ANSI code */
23
24#include <stdio.h>
25#include <stdlib.h>
26#include <math.h>
27#include <vorbis/codec.h>
28
29#ifdef _WIN32 /* We need the following two to set stdin/stdout to binary */
30#include <io.h>
31#include <fcntl.h>
32#endif
33
34#if defined(__MACOS__) && defined(__MWERKS__)
35#include <console.h>      /* CodeWarrior's Mac "command-line" support */
36#endif
37
38ogg_int16_t convbuffer[4096]; /* take 8k out of the data segment, not the stack */
39int convsize=4096;
40
41extern void _VDBG_dump(void);
42
43int main(){
44  ogg_sync_state   oy; /* sync and verify incoming physical bitstream */
45  ogg_stream_state os; /* take physical pages, weld into a logical
46                          stream of packets */
47  ogg_page         og; /* one Ogg bitstream page. Vorbis packets are inside */
48  ogg_packet       op; /* one raw packet of data for decode */
49
50  vorbis_info      vi; /* struct that stores all the static vorbis bitstream
51                          settings */
52  vorbis_comment   vc; /* struct that stores all the bitstream user comments */
53  vorbis_dsp_state vd; /* central working state for the packet->PCM decoder */
54  vorbis_block     vb; /* local working space for packet->PCM decode */
55
56  char *buffer;
57  int  bytes;
58
59#ifdef _WIN32 /* We need to set stdin/stdout to binary mode. Damn windows. */
60  /* Beware the evil ifdef. We avoid these where we can, but this one we
61     cannot. Don't add any more, you'll probably go to hell if you do. */
62  _setmode( _fileno( stdin ), _O_BINARY );
63  _setmode( _fileno( stdout ), _O_BINARY );
64#endif
65
66#if defined(macintosh) && defined(__MWERKS__)
67  {
68    int argc;
69    char **argv;
70    argc=ccommand(&argv); /* get a "command line" from the Mac user */
71                     /* this also lets the user set stdin and stdout */
72  }
73#endif
74
75  /********** Decode setup ************/
76
77  ogg_sync_init(&oy); /* Now we can read pages */
78
79  while(1){ /* we repeat if the bitstream is chained */
80    int eos=0;
81    int i;
82
83    /* grab some data at the head of the stream. We want the first page
84       (which is guaranteed to be small and only contain the Vorbis
85       stream initial header) We need the first page to get the stream
86       serialno. */
87
88    /* submit a 4k block to libvorbis' Ogg layer */
89    buffer=ogg_sync_buffer(&oy,4096);
90    bytes=fread(buffer,1,4096,stdin);
91    ogg_sync_wrote(&oy,bytes);
92
93    /* Get the first page. */
94    if(ogg_sync_pageout(&oy,&og)!=1){
95      /* have we simply run out of data?  If so, we're done. */
96      if(bytes<4096)break;
97
98      /* error case.  Must not be Vorbis data */
99      fprintf(stderr,"Input does not appear to be an Ogg bitstream.\n");
100      exit(1);
101    }
102
103    /* Get the serial number and set up the rest of decode. */
104    /* serialno first; use it to set up a logical stream */
105    ogg_stream_init(&os,ogg_page_serialno(&og));
106
107    /* extract the initial header from the first page and verify that the
108       Ogg bitstream is in fact Vorbis data */
109
110    /* I handle the initial header first instead of just having the code
111       read all three Vorbis headers at once because reading the initial
112       header is an easy way to identify a Vorbis bitstream and it's
113       useful to see that functionality seperated out. */
114
115    vorbis_info_init(&vi);
116    vorbis_comment_init(&vc);
117    if(ogg_stream_pagein(&os,&og)<0){
118      /* error; stream version mismatch perhaps */
119      fprintf(stderr,"Error reading first page of Ogg bitstream data.\n");
120      exit(1);
121    }
122
123    if(ogg_stream_packetout(&os,&op)!=1){
124      /* no page? must not be vorbis */
125      fprintf(stderr,"Error reading initial header packet.\n");
126      exit(1);
127    }
128
129    if(vorbis_synthesis_headerin(&vi,&vc,&op)<0){
130      /* error case; not a vorbis header */
131      fprintf(stderr,"This Ogg bitstream does not contain Vorbis "
132              "audio data.\n");
133      exit(1);
134    }
135
136    /* At this point, we're sure we're Vorbis. We've set up the logical
137       (Ogg) bitstream decoder. Get the comment and codebook headers and
138       set up the Vorbis decoder */
139
140    /* The next two packets in order are the comment and codebook headers.
141       They're likely large and may span multiple pages. Thus we read
142       and submit data until we get our two packets, watching that no
143       pages are missing. If a page is missing, error out; losing a
144       header page is the only place where missing data is fatal. */
145
146    i=0;
147    while(i<2){
148      while(i<2){
149        int result=ogg_sync_pageout(&oy,&og);
150        if(result==0)break; /* Need more data */
151        /* Don't complain about missing or corrupt data yet. We'll
152           catch it at the packet output phase */
153        if(result==1){
154          ogg_stream_pagein(&os,&og); /* we can ignore any errors here
155                                         as they'll also become apparent
156                                         at packetout */
157          while(i<2){
158            result=ogg_stream_packetout(&os,&op);
159            if(result==0)break;
160            if(result<0){
161              /* Uh oh; data at some point was corrupted or missing!
162                 We can't tolerate that in a header.  Die. */
163              fprintf(stderr,"Corrupt secondary header.  Exiting.\n");
164              exit(1);
165            }
166            result=vorbis_synthesis_headerin(&vi,&vc,&op);
167            if(result<0){
168              fprintf(stderr,"Corrupt secondary header.  Exiting.\n");
169              exit(1);
170            }
171            i++;
172          }
173        }
174      }
175      /* no harm in not checking before adding more */
176      buffer=ogg_sync_buffer(&oy,4096);
177      bytes=fread(buffer,1,4096,stdin);
178      if(bytes==0 && i<2){
179        fprintf(stderr,"End of file before finding all Vorbis headers!\n");
180        exit(1);
181      }
182      ogg_sync_wrote(&oy,bytes);
183    }
184
185    /* Throw the comments plus a few lines about the bitstream we're
186       decoding */
187    {
188      char **ptr=vc.user_comments;
189      while(*ptr){
190        fprintf(stderr,"%s\n",*ptr);
191        ++ptr;
192      }
193      fprintf(stderr,"\nBitstream is %d channel, %ldHz\n",vi.channels,vi.rate);
194      fprintf(stderr,"Encoded by: %s\n\n",vc.vendor);
195    }
196
197    convsize=4096/vi.channels;
198
199    /* OK, got and parsed all three headers. Initialize the Vorbis
200       packet->PCM decoder. */
201    if(vorbis_synthesis_init(&vd,&vi)==0){ /* central decode state */
202      vorbis_block_init(&vd,&vb);          /* local state for most of the decode
203                                              so multiple block decodes can
204                                              proceed in parallel. We could init
205                                              multiple vorbis_block structures
206                                              for vd here */
207
208      /* The rest is just a straight decode loop until end of stream */
209      while(!eos){
210        while(!eos){
211          int result=ogg_sync_pageout(&oy,&og);
212          if(result==0)break; /* need more data */
213          if(result<0){ /* missing or corrupt data at this page position */
214            fprintf(stderr,"Corrupt or missing data in bitstream; "
215                    "continuing...\n");
216          }else{
217            ogg_stream_pagein(&os,&og); /* can safely ignore errors at
218                                           this point */
219            while(1){
220              result=ogg_stream_packetout(&os,&op);
221
222              if(result==0)break; /* need more data */
223              if(result<0){ /* missing or corrupt data at this page position */
224                /* no reason to complain; already complained above */
225              }else{
226                /* we have a packet.  Decode it */
227                float **pcm;
228                int samples;
229
230                if(vorbis_synthesis(&vb,&op)==0) /* test for success! */
231                  vorbis_synthesis_blockin(&vd,&vb);
232                /*
233
234                **pcm is a multichannel float vector.  In stereo, for
235                example, pcm[0] is left, and pcm[1] is right.  samples is
236                the size of each channel.  Convert the float values
237                (-1.<=range<=1.) to whatever PCM format and write it out */
238
239                while((samples=vorbis_synthesis_pcmout(&vd,&pcm))>0){
240                  int j;
241                  int clipflag=0;
242                  int bout=(samples<convsize?samples:convsize);
243
244                  /* convert floats to 16 bit signed ints (host order) and
245                     interleave */
246                  for(i=0;i<vi.channels;i++){
247                    ogg_int16_t *ptr=convbuffer+i;
248                    float  *mono=pcm[i];
249                    for(j=0;j<bout;j++){
250#if 1
251                      int val=floor(mono[j]*32767.f+.5f);
252#else /* optional dither */
253                      int val=mono[j]*32767.f+drand48()-0.5f;
254#endif
255                      /* might as well guard against clipping */
256                      if(val>32767){
257                        val=32767;
258                        clipflag=1;
259                      }
260                      if(val<-32768){
261                        val=-32768;
262                        clipflag=1;
263                      }
264                      *ptr=val;
265                      ptr+=vi.channels;
266                    }
267                  }
268
269                  if(clipflag)
270                    fprintf(stderr,"Clipping in frame %ld\n",(long)(vd.sequence));
271
272
273                  fwrite(convbuffer,2*vi.channels,bout,stdout);
274
275                  vorbis_synthesis_read(&vd,bout); /* tell libvorbis how
276                                                      many samples we
277                                                      actually consumed */
278                }
279              }
280            }
281            if(ogg_page_eos(&og))eos=1;
282          }
283        }
284        if(!eos){
285          buffer=ogg_sync_buffer(&oy,4096);
286          bytes=fread(buffer,1,4096,stdin);
287          ogg_sync_wrote(&oy,bytes);
288          if(bytes==0)eos=1;
289        }
290      }
291
292      /* ogg_page and ogg_packet structs always point to storage in
293         libvorbis.  They're never freed or manipulated directly */
294
295      vorbis_block_clear(&vb);
296      vorbis_dsp_clear(&vd);
297    }else{
298      fprintf(stderr,"Error: Corrupt header during playback initialization.\n");
299    }
300
301    /* clean up this logical bitstream; before exit we see if we're
302       followed by another [chained] */
303
304    ogg_stream_clear(&os);
305    vorbis_comment_clear(&vc);
306    vorbis_info_clear(&vi);  /* must be called last */
307  }
308
309  /* OK, clean up the framer */
310  ogg_sync_clear(&oy);
311
312  fprintf(stderr,"Done.\n");
313  return(0);
314}
315