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: Oct 04 1999
19 ********************************************************************/
21 /* takes a stereo 16bit 44.1kHz WAV file from stdin and encodes it into
29 signed char readbuffer[READ*4+44]; /* out of the data segment, not the stack */
32 ogg_stream_state os; /* take physical pages, weld into a logical
34 ogg_page og; /* one Ogg bitstream page. Vorbis packets are inside */
35 ogg_packet op; /* one raw packet of data for decode */
37 vorbis_info vi; /* struct that stores all the static vorbis bitstream
39 vorbis_dsp_state vd; /* central working state for the packet->PCM decoder */
40 vorbis_block vb; /* local working space for packet->PCM decode */
44 /* we cheat on the WAV header; we just bypass 44 bytes and never
45 verify that it matches 16bit/stereo/44.1kHz. This is just an
46 example, after all. */
48 fread(readbuffer,1,44,stdin);
50 /********** Encode setup ************/
52 /* choose an encoding mode */
53 /* (mode 0: 44kHz stereo uncoupled, roughly 128kbps VBR) */
54 vorbis_info_modeset(&vi,0);
57 vorbis_info_addcomment(&vi,"Track encoded by encoder_example.c");
59 /* set up the analysis state and auxiliary encoding storage */
60 vorbis_analysis_init(&vd,&vi);
61 vorbis_block_init(&vd,&vb);
63 /* set up our packet->stream encoder */
64 ogg_stream_init(&os,0); /* serial number 0 is fine */
66 /* Vorbis streams begin with three headers; the initial header (with
67 most of the codec setup parameters) which is mandated by the Ogg
68 bitstream spec. The second header holds any comment fields. The
69 third header holds the bitstream codebook. We merely need to
70 make the headers, then pass them to libvorbis one at a time;
71 libvorbis handles the additional Ogg bitstream constraints */
75 ogg_packet header_comm;
76 ogg_packet header_code;
78 vorbis_info_headerout(&vi,&header,&header_comm,&header_code);
79 ogg_stream_packetin(&os,&header); /* automatically placed in its own
81 ogg_stream_packetin(&os,&header_comm);
82 ogg_stream_packetin(&os,&header_code);
84 /* no need to write out here. We'll get to that in the main loop */
89 long bytes=fread(readbuffer,1,READ*4,stdin); /* stereo hardwired here */
92 /* end of file. this can be done implicitly in the mainline,
93 but it's easier to see here in non-clever fashion.
94 Tell the library we're at end of stream so that it can handle
95 the last frame and mark end of stream in the output properly */
96 vorbis_analysis_wrote(&vd,0);
101 /* expose the buffer to submit data */
102 double **buffer=vorbis_analysis_buffer(&vd,READ);
104 /* uninterleave samples */
105 for(i=0;i<bytes/4;i++){
106 buffer[0][i]=((readbuffer[i*4+1]<<8)|
107 (0x00ff&(int)readbuffer[i*4]))/32768.;
108 buffer[1][i]=((readbuffer[i*4+3]<<8)|
109 (0x00ff&(int)readbuffer[i*4+2]))/32768.;
112 /* tell the library how much we actually submitted */
113 vorbis_analysis_wrote(&vd,i);
116 /* vorbis does some data preanalysis, then divvies up blocks for
117 more involved (potentially parallel) processing. Get a single
118 block for encoding now */
119 while(vorbis_analysis_blockout(&vd,&vb)==1){
122 vorbis_analysis(&vb,&op);
124 /* weld the packet into the bitstream */
125 ogg_stream_packetin(&os,&op);
127 /* write out pages (if any) */
129 int result=ogg_stream_pageout(&os,&og);
131 fwrite(og.header,1,og.header_len,stdout);
132 fwrite(og.body,1,og.body_len,stdout);
134 /* this could be set above, but for illustrative purposes, I do
135 it here (to show that vorbis does know where the stream ends) */
137 if(ogg_page_eos(&og))eos=1;
143 /* clean up and exit. vorbis_info_clear() must be called last */
145 ogg_stream_clear(&os);
146 vorbis_dsp_clear(&vd);
147 vorbis_block_clear(&vb);
148 vorbis_info_clear(&vi);
150 /* ogg_page and ogg_packet structs always point to storage in
151 libvorbis. They're never freed or manipulated directly */
153 fprintf(stderr,"Done.\n");