1 /********************************************************************
3 * THIS FILE IS PART OF THE Ogg Vorbis SOFTWARE CODEC SOURCE CODE. *
4 * USE, DISTRIBUTION AND REPRODUCTION OF THIS SOURCE IS GOVERNED BY *
5 * THE GNU PUBLIC LICENSE 2, WHICH IS INCLUDED WITH THIS SOURCE. *
6 * PLEASE READ THESE TERMS DISTRIBUTING. *
8 * THE OggSQUISH SOURCE CODE IS (C) COPYRIGHT 1994-1999 *
9 * by 1999 Monty <monty@xiph.org> and The XIPHOPHORUS Company *
10 * http://www.xiph.org/ *
12 ********************************************************************
14 function: simple example encoder
15 author: Monty <xiphmont@mit.edu>
16 modifications by: Monty
17 last modification date: Nov 16 1999
19 ********************************************************************/
21 /* takes a stereo 16bit 44.1kHz WAV file from stdin and encodes it into
24 /* Note that this is POSIX, not ANSI, code */
33 signed char readbuffer[READ*4+44]; /* out of the data segment, not the stack */
36 ogg_stream_state os; /* take physical pages, weld into a logical
38 ogg_page og; /* one Ogg bitstream page. Vorbis packets are inside */
39 ogg_packet op; /* one raw packet of data for decode */
41 vorbis_info vi; /* struct that stores all the static vorbis bitstream
43 vorbis_dsp_state vd; /* central working state for the packet->PCM decoder */
44 vorbis_block vb; /* local working space for packet->PCM decode */
48 /* we cheat on the WAV header; we just bypass 44 bytes and never
49 verify that it matches 16bit/stereo/44.1kHz. This is just an
50 example, after all. */
52 fread(readbuffer,1,44,stdin);
54 /********** Encode setup ************/
56 /* choose an encoding mode */
57 /* (mode 0: 44kHz stereo uncoupled, roughly 128kbps VBR) */
58 vorbis_info_modeset(&vi,0);
61 vorbis_info_addcomment(&vi,"Track encoded by encoder_example.c");
63 /* set up the analysis state and auxiliary encoding storage */
64 vorbis_analysis_init(&vd,&vi);
65 vorbis_block_init(&vd,&vb);
67 /* set up our packet->stream encoder */
68 /* pick a random serial number; that way we can more likely build
69 chained streams just by concatenation */
71 ogg_stream_init(&os,random());
73 /* Vorbis streams begin with three headers; the initial header (with
74 most of the codec setup parameters) which is mandated by the Ogg
75 bitstream spec. The second header holds any comment fields. The
76 third header holds the bitstream codebook. We merely need to
77 make the headers, then pass them to libvorbis one at a time;
78 libvorbis handles the additional Ogg bitstream constraints */
82 ogg_packet header_comm;
83 ogg_packet header_code;
85 vorbis_info_headerout(&vi,&header,&header_comm,&header_code);
86 ogg_stream_packetin(&os,&header); /* automatically placed in its own
88 ogg_stream_packetin(&os,&header_comm);
89 ogg_stream_packetin(&os,&header_code);
91 /* no need to write out here. We'll get to that in the main loop */
96 long bytes=fread(readbuffer,1,READ*4,stdin); /* stereo hardwired here */
99 /* end of file. this can be done implicitly in the mainline,
100 but it's easier to see here in non-clever fashion.
101 Tell the library we're at end of stream so that it can handle
102 the last frame and mark end of stream in the output properly */
103 vorbis_analysis_wrote(&vd,0);
108 /* expose the buffer to submit data */
109 double **buffer=vorbis_analysis_buffer(&vd,READ);
111 /* uninterleave samples */
112 for(i=0;i<bytes/4;i++){
113 buffer[0][i]=((readbuffer[i*4+1]<<8)|
114 (0x00ff&(int)readbuffer[i*4]))/32768.;
115 buffer[1][i]=((readbuffer[i*4+3]<<8)|
116 (0x00ff&(int)readbuffer[i*4+2]))/32768.;
119 /* tell the library how much we actually submitted */
120 vorbis_analysis_wrote(&vd,i);
123 /* vorbis does some data preanalysis, then divvies up blocks for
124 more involved (potentially parallel) processing. Get a single
125 block for encoding now */
126 while(vorbis_analysis_blockout(&vd,&vb)==1){
129 vorbis_analysis(&vb,&op);
131 /* weld the packet into the bitstream */
132 ogg_stream_packetin(&os,&op);
134 /* write out pages (if any) */
136 int result=ogg_stream_pageout(&os,&og);
138 fwrite(og.header,1,og.header_len,stdout);
139 fwrite(og.body,1,og.body_len,stdout);
141 /* this could be set above, but for illustrative purposes, I do
142 it here (to show that vorbis does know where the stream ends) */
144 if(ogg_page_eos(&og))eos=1;
150 /* clean up and exit. vorbis_info_clear() must be called last */
152 ogg_stream_clear(&os);
153 vorbis_dsp_clear(&vd);
154 vorbis_block_clear(&vb);
155 vorbis_info_clear(&vi);
157 /* ogg_page and ogg_packet structs always point to storage in
158 libvorbis. They're never freed or manipulated directly */
160 fprintf(stderr,"Done.\n");