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Diffstat (limited to 'examples')
| -rw-r--r-- | examples/encoder_example.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/examples/encoder_example.c b/examples/encoder_example.c new file mode 100644 index 00000000..b9dae40a --- /dev/null +++ b/examples/encoder_example.c @@ -0,0 +1,177 @@ +/******************************************************************** + * * + * THIS FILE IS PART OF THE Ogg Vorbis SOFTWARE CODEC SOURCE CODE. * + * USE, DISTRIBUTION AND REPRODUCTION OF THIS SOURCE IS GOVERNED BY * + * THE GNU PUBLIC LICENSE 2, WHICH IS INCLUDED WITH THIS SOURCE. * + * PLEASE READ THESE TERMS DISTRIBUTING. * + * * + * THE OggSQUISH SOURCE CODE IS (C) COPYRIGHT 1994-2000 * + * by Monty <monty@xiph.org> and The XIPHOPHORUS Company * + * http://www.xiph.org/ * + * * + ******************************************************************** + + function: simple example encoder + last mod: $Id: encoder_example.c,v 1.8.4.1 2000/08/15 08:33:35 xiphmont Exp $ + + ********************************************************************/ + +/* takes a stereo 16bit 44.1kHz WAV file from stdin and encodes it into + a Vorbis bitstream */ + +/* Note that this is POSIX, not ANSI, code */ + +#include <stdio.h> +#include <stdlib.h> +#include <time.h> +#include <math.h> +#include "vorbis/mode_A.h" + +#ifdef _WIN32 /* We need the following two to set stdin/stdout to binary */ +#include <io.h> +#include <fcntl.h> +#endif + + +#define READ 1024 +signed char readbuffer[READ*4+44]; /* out of the data segment, not the stack */ + +int main(){ + ogg_stream_state os; /* take physical pages, weld into a logical + stream of packets */ + ogg_page og; /* one Ogg bitstream page. Vorbis packets are inside */ + ogg_packet op; /* one raw packet of data for decode */ + + vorbis_info *vi; /* struct that stores all the static vorbis bitstream + settings */ + vorbis_comment vc; /* struct that stores all the user comments */ + + vorbis_dsp_state vd; /* central working state for the packet->PCM decoder */ + vorbis_block vb; /* local working space for packet->PCM decode */ + + int eos=0; + + /* we cheat on the WAV header; we just bypass 44 bytes and never + verify that it matches 16bit/stereo/44.1kHz. This is just an + example, after all. */ + +#ifdef _WIN32 /* We need to set stdin/stdout to binary mode. Damn windows. */ + /* Beware the evil ifdef. We avoid these where we can, but this one we + cannot. Don't add any more, you'll probably go to hell if you do. */ + _setmode( _fileno( stdin ), _O_BINARY ); + _setmode( _fileno( stdout ), _O_BINARY ); +#endif + + + fread(readbuffer,1,44,stdin); + + /********** Encode setup ************/ + + /* choose an encoding mode */ + /* (mode 0: 44kHz stereo uncoupled, roughly 128kbps VBR) */ + vi=&info_A; + + /* add a comment */ + vorbis_comment_init(&vc); + vorbis_comment_add(&vc,"Track encoded by encoder_example.c"); + + /* set up the analysis state and auxiliary encoding storage */ + vorbis_analysis_init(&vd,vi); + vorbis_block_init(&vd,&vb); + + /* set up our packet->stream encoder */ + /* pick a random serial number; that way we can more likely build + chained streams just by concatenation */ + srand(time(NULL)); + ogg_stream_init(&os,rand()); + + /* Vorbis streams begin with three headers; the initial header (with + most of the codec setup parameters) which is mandated by the Ogg + bitstream spec. The second header holds any comment fields. The + third header holds the bitstream codebook. We merely need to + make the headers, then pass them to libvorbis one at a time; + libvorbis handles the additional Ogg bitstream constraints */ + + { + ogg_packet header; + ogg_packet header_comm; + ogg_packet header_code; + + vorbis_analysis_headerout(&vd,&vc,&header,&header_comm,&header_code); + ogg_stream_packetin(&os,&header); /* automatically placed in its own + page */ + ogg_stream_packetin(&os,&header_comm); + ogg_stream_packetin(&os,&header_code); + + /* no need to write out here. We'll get to that in the main loop */ + } + + while(!eos){ + long i; + long bytes=fread(readbuffer,1,READ*4,stdin); /* stereo hardwired here */ + + if(bytes==0){ + /* end of file. this can be done implicitly in the mainline, + but it's easier to see here in non-clever fashion. + Tell the library we're at end of stream so that it can handle + the last frame and mark end of stream in the output properly */ + vorbis_analysis_wrote(&vd,0); + + }else{ + /* data to encode */ + + /* expose the buffer to submit data */ + double **buffer=vorbis_analysis_buffer(&vd,READ); + + /* uninterleave samples */ + for(i=0;i<bytes/4;i++){ + buffer[0][i]=((readbuffer[i*4+1]<<8)| + (0x00ff&(int)readbuffer[i*4]))/32768.; + buffer[1][i]=((readbuffer[i*4+3]<<8)| + (0x00ff&(int)readbuffer[i*4+2]))/32768.; + } + + /* tell the library how much we actually submitted */ + vorbis_analysis_wrote(&vd,i); + } + + /* vorbis does some data preanalysis, then divvies up blocks for + more involved (potentially parallel) processing. Get a single + block for encoding now */ + while(vorbis_analysis_blockout(&vd,&vb)==1){ + + /* analysis */ + vorbis_analysis(&vb,&op); + + /* weld the packet into the bitstream */ + ogg_stream_packetin(&os,&op); + + /* write out pages (if any) */ + while(!eos){ + int result=ogg_stream_pageout(&os,&og); + if(result==0)break; + fwrite(og.header,1,og.header_len,stdout); + fwrite(og.body,1,og.body_len,stdout); + + /* this could be set above, but for illustrative purposes, I do + it here (to show that vorbis does know where the stream ends) */ + + if(ogg_page_eos(&og))eos=1; + + } + } + } + + /* clean up and exit. vorbis_info_clear() must be called last */ + + ogg_stream_clear(&os); + vorbis_block_clear(&vb); + vorbis_dsp_clear(&vd); + + /* ogg_page and ogg_packet structs always point to storage in + libvorbis. They're never freed or manipulated directly */ + + fprintf(stderr,"Done.\n"); + return(0); +} + |