315 lines
12 KiB
C
Executable File
315 lines
12 KiB
C
Executable File
/********************************************************************
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* *
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* THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE. *
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* USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS *
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* GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
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* IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. *
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* *
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* THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2009 *
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* by the Xiph.Org Foundation http://www.xiph.org/ *
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* *
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********************************************************************
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function: simple example decoder
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last mod: $Id: decoder_example.c 16243 2009-07-10 02:49:31Z xiphmont $
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********************************************************************/
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/* Takes a vorbis bitstream from stdin and writes raw stereo PCM to
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stdout. Decodes simple and chained OggVorbis files from beginning
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to end. Vorbisfile.a is somewhat more complex than the code below. */
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/* Note that this is POSIX, not ANSI code */
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#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#include <vorbis/codec.h>
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#ifdef _WIN32 /* We need the following two to set stdin/stdout to binary */
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#include <io.h>
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#include <fcntl.h>
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#endif
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#if defined(__MACOS__) && defined(__MWERKS__)
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#include <console.h> /* CodeWarrior's Mac "command-line" support */
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#endif
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ogg_int16_t convbuffer[4096]; /* take 8k out of the data segment, not the stack */
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int convsize=4096;
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extern void _VDBG_dump(void);
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int main(){
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ogg_sync_state oy; /* sync and verify incoming physical bitstream */
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ogg_stream_state os; /* take physical pages, weld into a logical
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stream of packets */
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ogg_page og; /* one Ogg bitstream page. Vorbis packets are inside */
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ogg_packet op; /* one raw packet of data for decode */
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vorbis_info vi; /* struct that stores all the static vorbis bitstream
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settings */
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vorbis_comment vc; /* struct that stores all the bitstream user comments */
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vorbis_dsp_state vd; /* central working state for the packet->PCM decoder */
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vorbis_block vb; /* local working space for packet->PCM decode */
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char *buffer;
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int bytes;
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#ifdef _WIN32 /* We need to set stdin/stdout to binary mode. Damn windows. */
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/* Beware the evil ifdef. We avoid these where we can, but this one we
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cannot. Don't add any more, you'll probably go to hell if you do. */
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_setmode( _fileno( stdin ), _O_BINARY );
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_setmode( _fileno( stdout ), _O_BINARY );
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#endif
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#if defined(macintosh) && defined(__MWERKS__)
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{
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int argc;
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char **argv;
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argc=ccommand(&argv); /* get a "command line" from the Mac user */
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/* this also lets the user set stdin and stdout */
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}
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#endif
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/********** Decode setup ************/
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ogg_sync_init(&oy); /* Now we can read pages */
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while(1){ /* we repeat if the bitstream is chained */
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int eos=0;
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int i;
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/* grab some data at the head of the stream. We want the first page
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(which is guaranteed to be small and only contain the Vorbis
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stream initial header) We need the first page to get the stream
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serialno. */
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/* submit a 4k block to libvorbis' Ogg layer */
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buffer=ogg_sync_buffer(&oy,4096);
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bytes=fread(buffer,1,4096,stdin);
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ogg_sync_wrote(&oy,bytes);
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/* Get the first page. */
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if(ogg_sync_pageout(&oy,&og)!=1){
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/* have we simply run out of data? If so, we're done. */
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if(bytes<4096)break;
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/* error case. Must not be Vorbis data */
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fprintf(stderr,"Input does not appear to be an Ogg bitstream.\n");
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exit(1);
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}
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/* Get the serial number and set up the rest of decode. */
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/* serialno first; use it to set up a logical stream */
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ogg_stream_init(&os,ogg_page_serialno(&og));
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/* extract the initial header from the first page and verify that the
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Ogg bitstream is in fact Vorbis data */
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/* I handle the initial header first instead of just having the code
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read all three Vorbis headers at once because reading the initial
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header is an easy way to identify a Vorbis bitstream and it's
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useful to see that functionality seperated out. */
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vorbis_info_init(&vi);
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vorbis_comment_init(&vc);
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if(ogg_stream_pagein(&os,&og)<0){
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/* error; stream version mismatch perhaps */
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fprintf(stderr,"Error reading first page of Ogg bitstream data.\n");
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exit(1);
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}
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if(ogg_stream_packetout(&os,&op)!=1){
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/* no page? must not be vorbis */
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fprintf(stderr,"Error reading initial header packet.\n");
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exit(1);
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}
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if(vorbis_synthesis_headerin(&vi,&vc,&op)<0){
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/* error case; not a vorbis header */
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fprintf(stderr,"This Ogg bitstream does not contain Vorbis "
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"audio data.\n");
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exit(1);
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}
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/* At this point, we're sure we're Vorbis. We've set up the logical
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(Ogg) bitstream decoder. Get the comment and codebook headers and
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set up the Vorbis decoder */
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/* The next two packets in order are the comment and codebook headers.
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They're likely large and may span multiple pages. Thus we read
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and submit data until we get our two packets, watching that no
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pages are missing. If a page is missing, error out; losing a
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header page is the only place where missing data is fatal. */
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i=0;
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while(i<2){
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while(i<2){
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int result=ogg_sync_pageout(&oy,&og);
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if(result==0)break; /* Need more data */
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/* Don't complain about missing or corrupt data yet. We'll
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catch it at the packet output phase */
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if(result==1){
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ogg_stream_pagein(&os,&og); /* we can ignore any errors here
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as they'll also become apparent
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at packetout */
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while(i<2){
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result=ogg_stream_packetout(&os,&op);
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if(result==0)break;
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if(result<0){
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/* Uh oh; data at some point was corrupted or missing!
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We can't tolerate that in a header. Die. */
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fprintf(stderr,"Corrupt secondary header. Exiting.\n");
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exit(1);
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}
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result=vorbis_synthesis_headerin(&vi,&vc,&op);
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if(result<0){
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fprintf(stderr,"Corrupt secondary header. Exiting.\n");
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exit(1);
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}
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i++;
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}
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}
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}
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/* no harm in not checking before adding more */
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buffer=ogg_sync_buffer(&oy,4096);
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bytes=fread(buffer,1,4096,stdin);
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if(bytes==0 && i<2){
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fprintf(stderr,"End of file before finding all Vorbis headers!\n");
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exit(1);
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}
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ogg_sync_wrote(&oy,bytes);
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}
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/* Throw the comments plus a few lines about the bitstream we're
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decoding */
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{
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char **ptr=vc.user_comments;
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while(*ptr){
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fprintf(stderr,"%s\n",*ptr);
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++ptr;
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}
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fprintf(stderr,"\nBitstream is %d channel, %ldHz\n",vi.channels,vi.rate);
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fprintf(stderr,"Encoded by: %s\n\n",vc.vendor);
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}
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convsize=4096/vi.channels;
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/* OK, got and parsed all three headers. Initialize the Vorbis
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packet->PCM decoder. */
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if(vorbis_synthesis_init(&vd,&vi)==0){ /* central decode state */
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vorbis_block_init(&vd,&vb); /* local state for most of the decode
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so multiple block decodes can
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proceed in parallel. We could init
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multiple vorbis_block structures
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for vd here */
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/* The rest is just a straight decode loop until end of stream */
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while(!eos){
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while(!eos){
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int result=ogg_sync_pageout(&oy,&og);
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if(result==0)break; /* need more data */
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if(result<0){ /* missing or corrupt data at this page position */
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fprintf(stderr,"Corrupt or missing data in bitstream; "
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"continuing...\n");
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}else{
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ogg_stream_pagein(&os,&og); /* can safely ignore errors at
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this point */
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while(1){
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result=ogg_stream_packetout(&os,&op);
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if(result==0)break; /* need more data */
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if(result<0){ /* missing or corrupt data at this page position */
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/* no reason to complain; already complained above */
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}else{
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/* we have a packet. Decode it */
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float **pcm;
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int samples;
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if(vorbis_synthesis(&vb,&op)==0) /* test for success! */
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vorbis_synthesis_blockin(&vd,&vb);
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/*
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**pcm is a multichannel float vector. In stereo, for
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example, pcm[0] is left, and pcm[1] is right. samples is
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the size of each channel. Convert the float values
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(-1.<=range<=1.) to whatever PCM format and write it out */
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while((samples=vorbis_synthesis_pcmout(&vd,&pcm))>0){
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int j;
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int clipflag=0;
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int bout=(samples<convsize?samples:convsize);
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/* convert floats to 16 bit signed ints (host order) and
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interleave */
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for(i=0;i<vi.channels;i++){
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ogg_int16_t *ptr=convbuffer+i;
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float *mono=pcm[i];
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for(j=0;j<bout;j++){
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#if 1
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int val=floor(mono[j]*32767.f+.5f);
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#else /* optional dither */
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int val=mono[j]*32767.f+drand48()-0.5f;
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#endif
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/* might as well guard against clipping */
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if(val>32767){
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val=32767;
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clipflag=1;
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}
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if(val<-32768){
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val=-32768;
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clipflag=1;
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}
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*ptr=val;
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ptr+=vi.channels;
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}
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}
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if(clipflag)
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fprintf(stderr,"Clipping in frame %ld\n",(long)(vd.sequence));
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fwrite(convbuffer,2*vi.channels,bout,stdout);
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vorbis_synthesis_read(&vd,bout); /* tell libvorbis how
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many samples we
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actually consumed */
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}
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}
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}
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if(ogg_page_eos(&og))eos=1;
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}
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}
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if(!eos){
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buffer=ogg_sync_buffer(&oy,4096);
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bytes=fread(buffer,1,4096,stdin);
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ogg_sync_wrote(&oy,bytes);
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if(bytes==0)eos=1;
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}
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}
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/* ogg_page and ogg_packet structs always point to storage in
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libvorbis. They're never freed or manipulated directly */
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vorbis_block_clear(&vb);
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vorbis_dsp_clear(&vd);
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}else{
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fprintf(stderr,"Error: Corrupt header during playback initialization.\n");
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}
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/* clean up this logical bitstream; before exit we see if we're
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followed by another [chained] */
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ogg_stream_clear(&os);
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vorbis_comment_clear(&vc);
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vorbis_info_clear(&vi); /* must be called last */
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}
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/* OK, clean up the framer */
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ogg_sync_clear(&oy);
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fprintf(stderr,"Done.\n");
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return(0);
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}
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