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source: vbox/trunk/src/libs/libvorbis-1.3.7/examples/decoder_example.c@ 105945

Last change on this file since 105945 was 96468, checked in by vboxsync, 2 years ago

libs/libvorbis-1.3.7: Re-exporting, hopefully this time everything is there. bugref:10275

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  • Property svn:keywords set to Author Date Id Revision
File size: 11.3 KB
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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 https://xiph.org/ *
10 * *
11 ********************************************************************
12
13 function: simple example decoder
14
15 ********************************************************************/
16
17/* Takes a vorbis bitstream from stdin and writes raw stereo PCM to
18 stdout. Decodes simple and chained OggVorbis files from beginning
19 to end. Vorbisfile.a is somewhat more complex than the code below. */
20
21/* Note that this is POSIX, not ANSI code */
22
23#include <stdio.h>
24#include <stdlib.h>
25#include <math.h>
26#include <vorbis/codec.h>
27
28#ifdef _WIN32 /* We need the following two to set stdin/stdout to binary */
29#include <io.h>
30#include <fcntl.h>
31#endif
32
33#if defined(__MACOS__) && defined(__MWERKS__)
34#include <console.h> /* CodeWarrior's Mac "command-line" support */
35#endif
36
37ogg_int16_t convbuffer[4096]; /* take 8k out of the data segment, not the stack */
38int convsize=4096;
39
40extern void _VDBG_dump(void);
41
42int main(){
43 ogg_sync_state oy; /* sync and verify incoming physical bitstream */
44 ogg_stream_state os; /* take physical pages, weld into a logical
45 stream of packets */
46 ogg_page og; /* one Ogg bitstream page. Vorbis packets are inside */
47 ogg_packet op; /* one raw packet of data for decode */
48
49 vorbis_info vi; /* struct that stores all the static vorbis bitstream
50 settings */
51 vorbis_comment vc; /* struct that stores all the bitstream user comments */
52 vorbis_dsp_state vd; /* central working state for the packet->PCM decoder */
53 vorbis_block vb; /* local working space for packet->PCM decode */
54
55 char *buffer;
56 int bytes;
57
58#ifdef _WIN32 /* We need to set stdin/stdout to binary mode. Damn windows. */
59 /* Beware the evil ifdef. We avoid these where we can, but this one we
60 cannot. Don't add any more, you'll probably go to hell if you do. */
61 _setmode( _fileno( stdin ), _O_BINARY );
62 _setmode( _fileno( stdout ), _O_BINARY );
63#endif
64
65#if defined(macintosh) && defined(__MWERKS__)
66 {
67 int argc;
68 char **argv;
69 argc=ccommand(&argv); /* get a "command line" from the Mac user */
70 /* this also lets the user set stdin and stdout */
71 }
72#endif
73
74 /********** Decode setup ************/
75
76 ogg_sync_init(&oy); /* Now we can read pages */
77
78 while(1){ /* we repeat if the bitstream is chained */
79 int eos=0;
80 int i;
81
82 /* grab some data at the head of the stream. We want the first page
83 (which is guaranteed to be small and only contain the Vorbis
84 stream initial header) We need the first page to get the stream
85 serialno. */
86
87 /* submit a 4k block to libvorbis' Ogg layer */
88 buffer=ogg_sync_buffer(&oy,4096);
89 bytes=fread(buffer,1,4096,stdin);
90 ogg_sync_wrote(&oy,bytes);
91
92 /* Get the first page. */
93 if(ogg_sync_pageout(&oy,&og)!=1){
94 /* have we simply run out of data? If so, we're done. */
95 if(bytes<4096)break;
96
97 /* error case. Must not be Vorbis data */
98 fprintf(stderr,"Input does not appear to be an Ogg bitstream.\n");
99 exit(1);
100 }
101
102 /* Get the serial number and set up the rest of decode. */
103 /* serialno first; use it to set up a logical stream */
104 ogg_stream_init(&os,ogg_page_serialno(&og));
105
106 /* extract the initial header from the first page and verify that the
107 Ogg bitstream is in fact Vorbis data */
108
109 /* I handle the initial header first instead of just having the code
110 read all three Vorbis headers at once because reading the initial
111 header is an easy way to identify a Vorbis bitstream and it's
112 useful to see that functionality seperated out. */
113
114 vorbis_info_init(&vi);
115 vorbis_comment_init(&vc);
116 if(ogg_stream_pagein(&os,&og)<0){
117 /* error; stream version mismatch perhaps */
118 fprintf(stderr,"Error reading first page of Ogg bitstream data.\n");
119 exit(1);
120 }
121
122 if(ogg_stream_packetout(&os,&op)!=1){
123 /* no page? must not be vorbis */
124 fprintf(stderr,"Error reading initial header packet.\n");
125 exit(1);
126 }
127
128 if(vorbis_synthesis_headerin(&vi,&vc,&op)<0){
129 /* error case; not a vorbis header */
130 fprintf(stderr,"This Ogg bitstream does not contain Vorbis "
131 "audio data.\n");
132 exit(1);
133 }
134
135 /* At this point, we're sure we're Vorbis. We've set up the logical
136 (Ogg) bitstream decoder. Get the comment and codebook headers and
137 set up the Vorbis decoder */
138
139 /* The next two packets in order are the comment and codebook headers.
140 They're likely large and may span multiple pages. Thus we read
141 and submit data until we get our two packets, watching that no
142 pages are missing. If a page is missing, error out; losing a
143 header page is the only place where missing data is fatal. */
144
145 i=0;
146 while(i<2){
147 while(i<2){
148 int result=ogg_sync_pageout(&oy,&og);
149 if(result==0)break; /* Need more data */
150 /* Don't complain about missing or corrupt data yet. We'll
151 catch it at the packet output phase */
152 if(result==1){
153 ogg_stream_pagein(&os,&og); /* we can ignore any errors here
154 as they'll also become apparent
155 at packetout */
156 while(i<2){
157 result=ogg_stream_packetout(&os,&op);
158 if(result==0)break;
159 if(result<0){
160 /* Uh oh; data at some point was corrupted or missing!
161 We can't tolerate that in a header. Die. */
162 fprintf(stderr,"Corrupt secondary header. Exiting.\n");
163 exit(1);
164 }
165 result=vorbis_synthesis_headerin(&vi,&vc,&op);
166 if(result<0){
167 fprintf(stderr,"Corrupt secondary header. Exiting.\n");
168 exit(1);
169 }
170 i++;
171 }
172 }
173 }
174 /* no harm in not checking before adding more */
175 buffer=ogg_sync_buffer(&oy,4096);
176 bytes=fread(buffer,1,4096,stdin);
177 if(bytes==0 && i<2){
178 fprintf(stderr,"End of file before finding all Vorbis headers!\n");
179 exit(1);
180 }
181 ogg_sync_wrote(&oy,bytes);
182 }
183
184 /* Throw the comments plus a few lines about the bitstream we're
185 decoding */
186 {
187 char **ptr=vc.user_comments;
188 while(*ptr){
189 fprintf(stderr,"%s\n",*ptr);
190 ++ptr;
191 }
192 fprintf(stderr,"\nBitstream is %d channel, %ldHz\n",vi.channels,vi.rate);
193 fprintf(stderr,"Encoded by: %s\n\n",vc.vendor);
194 }
195
196 convsize=4096/vi.channels;
197
198 /* OK, got and parsed all three headers. Initialize the Vorbis
199 packet->PCM decoder. */
200 if(vorbis_synthesis_init(&vd,&vi)==0){ /* central decode state */
201 vorbis_block_init(&vd,&vb); /* local state for most of the decode
202 so multiple block decodes can
203 proceed in parallel. We could init
204 multiple vorbis_block structures
205 for vd here */
206
207 /* The rest is just a straight decode loop until end of stream */
208 while(!eos){
209 while(!eos){
210 int result=ogg_sync_pageout(&oy,&og);
211 if(result==0)break; /* need more data */
212 if(result<0){ /* missing or corrupt data at this page position */
213 fprintf(stderr,"Corrupt or missing data in bitstream; "
214 "continuing...\n");
215 }else{
216 ogg_stream_pagein(&os,&og); /* can safely ignore errors at
217 this point */
218 while(1){
219 result=ogg_stream_packetout(&os,&op);
220
221 if(result==0)break; /* need more data */
222 if(result<0){ /* missing or corrupt data at this page position */
223 /* no reason to complain; already complained above */
224 }else{
225 /* we have a packet. Decode it */
226 float **pcm;
227 int samples;
228
229 if(vorbis_synthesis(&vb,&op)==0) /* test for success! */
230 vorbis_synthesis_blockin(&vd,&vb);
231 /*
232
233 **pcm is a multichannel float vector. In stereo, for
234 example, pcm[0] is left, and pcm[1] is right. samples is
235 the size of each channel. Convert the float values
236 (-1.<=range<=1.) to whatever PCM format and write it out */
237
238 while((samples=vorbis_synthesis_pcmout(&vd,&pcm))>0){
239 int j;
240 int clipflag=0;
241 int bout=(samples<convsize?samples:convsize);
242
243 /* convert floats to 16 bit signed ints (host order) and
244 interleave */
245 for(i=0;i<vi.channels;i++){
246 ogg_int16_t *ptr=convbuffer+i;
247 float *mono=pcm[i];
248 for(j=0;j<bout;j++){
249#if 1
250 int val=floor(mono[j]*32767.f+.5f);
251#else /* optional dither */
252 int val=mono[j]*32767.f+drand48()-0.5f;
253#endif
254 /* might as well guard against clipping */
255 if(val>32767){
256 val=32767;
257 clipflag=1;
258 }
259 if(val<-32768){
260 val=-32768;
261 clipflag=1;
262 }
263 *ptr=val;
264 ptr+=vi.channels;
265 }
266 }
267
268 if(clipflag)
269 fprintf(stderr,"Clipping in frame %ld\n",(long)(vd.sequence));
270
271
272 fwrite(convbuffer,2*vi.channels,bout,stdout);
273
274 vorbis_synthesis_read(&vd,bout); /* tell libvorbis how
275 many samples we
276 actually consumed */
277 }
278 }
279 }
280 if(ogg_page_eos(&og))eos=1;
281 }
282 }
283 if(!eos){
284 buffer=ogg_sync_buffer(&oy,4096);
285 bytes=fread(buffer,1,4096,stdin);
286 ogg_sync_wrote(&oy,bytes);
287 if(bytes==0)eos=1;
288 }
289 }
290
291 /* ogg_page and ogg_packet structs always point to storage in
292 libvorbis. They're never freed or manipulated directly */
293
294 vorbis_block_clear(&vb);
295 vorbis_dsp_clear(&vd);
296 }else{
297 fprintf(stderr,"Error: Corrupt header during playback initialization.\n");
298 }
299
300 /* clean up this logical bitstream; before exit we see if we're
301 followed by another [chained] */
302
303 ogg_stream_clear(&os);
304 vorbis_comment_clear(&vc);
305 vorbis_info_clear(&vi); /* must be called last */
306 }
307
308 /* OK, clean up the framer */
309 ogg_sync_clear(&oy);
310
311 fprintf(stderr,"Done.\n");
312 return(0);
313}
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