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269 lines
6.2 KiB
269 lines
6.2 KiB
/*
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stores information after we found a header.
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Copyright (C) 2000 Martin Vogt
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU Library General Public License as published by
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the Free Software Foundation.
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For more information look at the file COPYRIGHT in this package
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*/
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#include "mpegAudioHeader.h"
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#define DEBUG_HEADER(x)
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//#define DEBUG_HEADER(x) x
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#include <iostream>
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using namespace std;
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static const int frequencies[3][3]= {
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{44100,48000,32000}, // MPEG 1
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{22050,24000,16000}, // MPEG 2
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{11025,12000,8000} // MPEG 2.5
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};
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static int translate[3][2][16] = { { { 2,0,0,2,2,2,3,3,3,3,3,3,3,3,3,2 } ,
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{ 2,0,0,0,0,0,0,2,2,2,3,3,3,3,3,2 } } ,
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{ { 2,0,0,2,2,2,2,2,2,2,2,2,2,2,2,2 } ,
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{ 2,0,0,0,0,0,0,2,2,2,2,2,2,2,2,2 } } ,
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{ { 2,1,1,2,2,2,3,3,3,3,3,3,3,3,3,2 } ,
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{ 2,1,1,1,1,1,1,2,2,2,3,3,3,3,3,2 } } };
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static int sblims[5] = { 8 , 12 , 27, 30 , 30 };
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static const int bitrate[2][3][15]= {
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// MPEG 1
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{{0,32,64,96,128,160,192,224,256,288,320,352,384,416,448},
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{0,32,48,56,64,80,96,112,128,160,192,224,256,320,384},
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{0,32,40,48,56,64,80,96,112,128,160,192,224,256,320}},
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// MPEG 2
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{{0,32,48,56,64,80,96,112,128,144,160,176,192,224,256},
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{0,8,16,24,32,40,48,56,64,80,96,112,128,144,160},
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{0,8,16,24,32,40,48,56,64,80,96,112,128,144,160}}
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};
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MpegAudioHeader::MpegAudioHeader() {
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}
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MpegAudioHeader::~MpegAudioHeader() {
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}
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int MpegAudioHeader::getChannelbitrate() {
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cout << "getChannelbitrate not implemented"<<endl;
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return 0;
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}
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int MpegAudioHeader::parseHeader(unsigned char* buf){
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int c;
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int mpeg25=false;
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// Analyzing
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header[0]=buf[0];
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header[1]=buf[1];
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header[2]=buf[2];
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header[3]=buf[3];
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c=buf[1];
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lmpeg25=false;
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if ( (c&0xf0) == 0xe0) {
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lmpeg25=true;
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}
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c&=0xf;
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protection=c&1;
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layer=4-((c>>1)&3);
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// we catch the layer==4 error later, for now go on with parsing
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version=(int)(((c>>3)&1)^1);
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if ((version==0) && lmpeg25) {
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DEBUG_HEADER(cout << "wrong lsf/mpeg25 combination"<<endl;)
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return false;
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}
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c=buf[2];
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c=((c))>>1;
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padding=(c&1);
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c>>=1;
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frequency=(int)(c&3);
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c>>=2;
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bitrateindex=(int)c;
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if(bitrateindex>=15) {
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DEBUG_HEADER(cout << "bitrateindex error"<<endl;)
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return false;
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}
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c=buf[3];
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c=((unsigned int)(c))>>4;
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extendedmode=c&3;
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mode=(int)(c>>2);
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// Making information
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inputstereo= (mode==_MODE_SINGLE)?0:1;
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//
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// frequency can be 0,1 or 2 but the mask above allows 3 as well
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// check now.
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if (frequency > 2) {
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DEBUG_HEADER(cout << "frequency value out of range"<<endl;)
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return false;
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}
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//
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// does not belong here should be in the layer specific parts. [START]
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//
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switch(layer) {
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case 3:
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subbandnumber=0;
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stereobound=0;
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tableindex=0;
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break;
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case 2:
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tableindex = translate[frequency][inputstereo][bitrateindex];
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subbandnumber = sblims[tableindex];
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stereobound = subbandnumber;
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/*
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Now merge the tableindex, for the bitalloclengthtable
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*/
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tableindex=tableindex>>1;
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if(mode==_MODE_SINGLE)stereobound=0;
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if(mode==_MODE_JOINT)stereobound=(extendedmode+1)<<2;
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break;
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case 1:
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subbandnumber=MAXSUBBAND;
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stereobound=subbandnumber;
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tableindex=0;
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if(mode==_MODE_SINGLE)stereobound=0;
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if(mode==_MODE_JOINT)stereobound=(extendedmode+1)<<2;
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break;
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default:
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DEBUG_HEADER(cout <<"unknown layer"<<endl;)
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return false;
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}
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//
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// does not belong here should be in the layer specific parts. [END]
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//
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frequencyHz=frequencies[version+lmpeg25][frequency];
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// framesize & slots
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if(layer==1) {
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if (frequencyHz <= 0) {
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return false;
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}
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framesize=(12000*bitrate[version][0][bitrateindex])/frequencyHz;
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if(frequency==_FREQUENCY_44100 && padding)framesize++;
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framesize<<=2;
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} else {
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int freq=frequencyHz<<version;
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if (freq <= 0) {
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return false;
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}
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framesize=(144000*bitrate[version][layer-1][bitrateindex])/freq;
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if(padding)framesize++;
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if(layer==3) {
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if(version)
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layer3slots=framesize-((mode==_MODE_SINGLE)?9:17)
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-(protection?0:2)
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-4;
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else
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layer3slots=framesize-((mode==_MODE_SINGLE)?17:32)
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-(protection?0:2)
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-4;
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}
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}
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if (framesize <= 0) {
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DEBUG_HEADER(cout << "framesize negative"<<endl;)
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return false;
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}
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return true;
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}
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int MpegAudioHeader::getpcmperframe() {
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int s;
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s=32;
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if(layer==3) {
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s*=18;
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if(version==0)s*=2;
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}
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else {
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s*=SCALEBLOCK;
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if(layer==2)s*=3;
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}
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return s;
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}
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void MpegAudioHeader::copyTo(MpegAudioHeader* dest) {
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dest->protection=protection;
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dest->layer=layer;
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dest->version=version;
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dest->padding=padding;
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dest->frequency=frequency;
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dest->frequencyHz=frequencyHz;
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dest->bitrateindex=bitrateindex;
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dest->extendedmode=extendedmode;
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dest->mode=mode;
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dest->inputstereo=inputstereo;
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dest->channelbitrate=channelbitrate;
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dest->tableindex=tableindex;
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dest->subbandnumber=subbandnumber;
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dest->stereobound=stereobound;
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dest->framesize=framesize;
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dest->layer3slots=layer3slots;
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dest->lmpeg25=lmpeg25;
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}
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void MpegAudioHeader::print(const char* name) {
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cout << "MpegAudioHeader [START]:"<<name<<endl;
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printf("header:%1x%1x%1x%1x\n",header[0],header[1],header[2],header[3]);
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cout << "getProtection:"<<getProtection()<<endl;
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cout << "getLayer:"<<getLayer()<<endl;
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cout << "getVersion:"<<getVersion()<<endl;
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cout << "getPadding:"<<getPadding()<<endl;
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cout << "getFrequency:"<<getFrequency()<<endl;
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cout << "getFrequencyHz:"<<getFrequencyHz()<<endl;
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cout << "getBitrateindex:"<<getBitrateindex()<<endl;
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cout << "getExtendedmode:"<<getExtendedmode()<<endl;
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cout << "getMode():"<<getMode()<<endl;
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cout << "getInputstereo:"<<getInputstereo()<<endl;
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cout << "getChannelbitrate:"<<getChannelbitrate()<<endl;
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cout << "getTableindex:"<<getTableindex()<<endl;
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cout << "getSubbandnumber:"<<getSubbandnumber()<<endl;
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cout << "getStereobound:"<<getStereobound()<<endl;
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cout << "getFramesize:"<<getFramesize()<<endl;
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cout << "getLayer3slots:"<<getLayer3slots()<<endl;
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cout << "getpcmperframe:"<<getpcmperframe()<<endl;
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cout << "MpegAudioHeader [END]:"<<name<<endl;
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}
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