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<title>vorbisfile - Example Code</title>
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<link rel=stylesheet href="style.css" type="text/css">
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</head>
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<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
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Vorbisfile documentation
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vorbisfile version 1.3.2 - 20101101
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Example Code: seeking
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The following is a run-through of the seeking example program supplied
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with vorbisfile - seeking_test.c.
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This program tests the vorbisfile ov_time_seek function by seeking to random points within the file.
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First, relevant headers, including vorbis-specific "codec.h" and "vorbisfile.h" have to be included.
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#include <stdlib.h>
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#include <stdio.h>
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#include "vorbis/codec.h"
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#include "vorbis/vorbisfile.h"
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Inside main(), we declare our primary OggVorbis_File structure. We also declare other helpful variables to track our progress within the file.
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int main(){
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OggVorbis_File ov;
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int i;
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This example takes its input on stdin which is in 'text' mode by default under Windows; this will corrupt the input data unless set to binary mode. This applies only to Windows.
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#ifdef _WIN32 /* We need to set stdin to binary mode under Windows */
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_setmode( _fileno( stdin ), _O_BINARY );
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#endif
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ov_open() must be
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called to initialize the OggVorbis_File structure with default values.
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ov_open_callbacks() also checks to ensure that we're reading Vorbis format and not something else.
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if(ov_open_callbacks(stdin,&ov,NULL,-1, OV_CALLBACKS_NOCLOSE)<0){
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printf("Could not open input as an OggVorbis file.\n\n");
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exit(1);
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}
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First we check to make sure the stream is seekable using ov_seekable.
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Then we seek to 100 random spots in the bitstream using ov_time_seek with randomly generated values.
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/* print details about each logical bitstream in the input */
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if(ov_seekable(&ov)){
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double length=ov_time_total(&ov,-1);
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printf("testing seeking to random places in %g seconds....\n",length);
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for(i=0;i<100;i++){
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double val=(double)rand()/RAND_MAX*length;
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ov_time_seek(&ov,val);
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printf("\r\t%d [%gs]... ",i,val);
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fflush(stdout);
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}
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printf("\r \nOK.\n\n");
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}else{
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printf("Standard input was not seekable.\n");
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}
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When we're done seeking, we need to call ov_clear() to release the bitstream.
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ov_clear(&ov);
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return 0;
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}
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The full source for seeking_test.c can be found with the vorbis
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distribution in seeking_test.c.
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copyright © 2000-2010 Xiph.Org
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Ogg Vorbis
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Vorbisfile documentation
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vorbisfile version 1.3.2 - 20101101
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</body>
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</html>
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