调用CImg库显示WAV格式音频波形
最近在做傅里叶变换和小波变换时经常要通过显示波形来检验算法，但通过visual studio之类显示波形又显得麻烦，而且不能跨平台。
CImg是一个跨平台的C++的图像处理库，提供的图像处理等功能十分强大，而且加入项目中十分轻便，只需将头文件包含在项目中即可，十分轻便。
可自行到http://www.cimg.eu/下载
利用它来在linux、Mac OS X中显示波形，再合适不过了，下面是音频波形显示的代码。
主函数
main.cpp
#include <iostream> #include "wavfile.h" #include "CImg.h" using namespace std; using namespace cimg_library; using namespace AudioUtils; int main(void) { WaveFile *wf=new WaveFile(); /* 读取本目录里的audio.wav文件，并生成波形 */ wf->readwav("audio.wav"); int datalength=wf->size()/wf->bit(); wf->output_WAVfile_info(); int *data=(int*)malloc(sizeof(int)*datalength); for(int i=0;i<datalength;i++) { data[i]=(float)(wf->data[i]/100); } /* 调用CImg显示波形 */ const unsigned char red[] = { 255, 0, 0 }, yellow[] = { 255, 255, 0 }, green[] = { 0, 255, 0 }; /* 一维信号 */ int num=wf->size()/(8*(wf->bit())); CImg<float> signal_wav(num,1, 1, 1, 0); for(int i=0;i<num;i++) { signal_wav[i]=(data[i*8])*100; } CImg<unsigned char> signal_visu( 1200, 400, 1, 3, 0 ); /* 画格子 */ signal_visu.draw_grid( 50, 50, 0, 0, 0, 0, yellow, 0.5 ); signal_visu.draw_graph(signal_wav,red,1,3,0,35000,-35000,0); /* 画波形 */ CImgDisplay main_disp_wav (signal_visu, "signal" ); getchar(); return 0; }
wavfile.h
读取WAV格式文件
1 #ifndef WAVFILE_H 2 #define WAVFILE_H 3 #include <iostream> 4 #include <fstream> 5 using namespace std; 6 7 /* 8 BYTE=unsigned char(完全等同) WORD=unsigned short(完全等同) DWORD=unsigned long(完全等同) 9 10 unsigned char是无符号字节型 11 */ 12 namespace AudioUtils 13 { 14 /* 15 RIFF WAVE Chunk 16 ================================== 17 | |所占字节数| 具体内容 | 18 ================================== 19 | ID | 4 Bytes | 'RIFF' | 20 ---------------------------------- 21 | Size | 4 Bytes | | 22 ---------------------------------- 23 | Type | 4 Bytes | 'WAVE' | 24 ---------------------------------- 25 26 27 */ 28 class RiffBlock 29 { 30 public: 31 void ReadRiff(ifstream &infile) 32 { 33 int i=0; 34 for(i=0;i<4;i++) 35 { 36 infile.read((char*)&m_RiffID[i],1); 37 } 38 infile.read((char*)&m_RiffSize,4); 39 for(i=0;i<4;i++) 40 { 41 infile.read((char*)&Format[i],1); 42 } 43 } 44 45 /* 46 此处应当声明为pravte 用函数return, 不安全代码，暂简略处理 47 */ 48 unsigned char m_RiffID[4]; 49 unsigned long m_RiffSize; 50 unsigned char Format[4]; 51 }; 52 /* 53 ==================================================================== 54 | | 字节数 | 具体内容 | 55 ==================================================================== 56 | ID | 4 Bytes | 'fmt ' | 57 -------------------------------------------------------------------- 58 | Size | 4 Bytes | 数值为16或18，18则最后又附加信息 | 59 -------------------------------------------------------------------- ---- 60 | FormatTag | 2 Bytes | 编码方式，一般为0x0001 | | 61 -------------------------------------------------------------------- | 62 | Channels | 2 Bytes | 声道数目，1--单声道；2--双声道 | | 63 -------------------------------------------------------------------- | 64 | SamplesPerSec | 4 Bytes | 采样频率 | | 65 -------------------------------------------------------------------- | 66 | AvgBytesPerSec| 4 Bytes | 每秒所需字节数 | |===> WAVE_FORMAT 67 -------------------------------------------------------------------- | 68 | BlockAlign | 2 Bytes | 数据块对齐单位(每个采样需要的字节数) | | 69 -------------------------------------------------------------------- | 70 | BitsPerSample | 2 Bytes | 每个采样需要的bit数 | | 71 -------------------------------------------------------------------- | 72 | | 2 Bytes | 附加信息（可选，通过Size来判断有无） | | 73 -------------------------------------------------------------------- ---- 74 75 */ 76 class FmtBlock 77 { 78 public: 79 //seekg()移动文件指针 80 void ReadFmt(ifstream &infile) 81 { 82 int i=0; 83 for(i=0;i<4;i++) 84 { 85 infile.read((char*)&m_FmtID[i],1); 86 } 87 infile.read((char*)&m_FmtSize,4); 88 int size=m_FmtSize; 89 infile.read((char*)&m_FmtTag,2); 90 infile.read((char*)&m_Channels,2); 91 infile.read((char*)&m_SamplesPerSec,4); 92 infile.read((char*)&m_AverageBytesPerSec,4); 93 infile.read((char*)&m_BlockAlign,2); 94 infile.read((char*)&m_BitsPerSample,2); 95 if(size==18) 96 { 97 infile.read((char*)&m_OtherMeg,2); 98 } 99 } 100 101 int BitsPerSample() 102 { 103 return (m_BitsPerSample/8); 104 } 105 106 unsigned char m_FmtID[4]; 107 unsigned long m_FmtSize; 108 unsigned short m_FmtTag; 109 unsigned short m_Channels; 110 unsigned long m_SamplesPerSec; 111 unsigned long m_AverageBytesPerSec; 112 unsigned short m_BlockAlign; 113 unsigned short m_BitsPerSample; 114 unsigned short m_OtherMeg; 115 }; 116 117 /* 118 Data Chunk 119 ================================== 120 | |所占字节数| 具体内容 | 121 ================================== 122 | ID | 4 Bytes | 'data' | 123 ---------------------------------- 124 | Size | 4 Bytes | | 125 ---------------------------------- 126 | data | | | 127 ---------------------------------- 128 129 1Bytes 130 --------------------------------------------------------------------- 131 | 单声道 | 取样1 | 取样2 | 取样3 | 取样4 | 132 | | -------------------------------------------------------- 133 | 8bit量化 | 声道0 | 声道0 | 声道0 | 声道0 | 134 --------------------------------------------------------------------- 135 | 双声道 | 取样1 | 取样2 | 136 | |-------------------------------------------------------- 137 | 8bit量化 | 声道0(左) | 声道1(右) | 声道0(左) | 声道1(右) | 138 1WORD 139 --------------------------------------------------------------------- 140 | | 取样1 | 取样2 | 141 | 单声道 |-------------------------------------------------------- 142 | 16bit量化 | 声道0 | 声道0 | 声道0 | 声道0 | 143 | | (低位字节) | (高位字节) | (低位字节) | (高位字节) | 144 --------------------------------------------------------------------- 145 | | 取样1 | 146 | 双声道 |-------------------------------------------------------- 147 | 16bit量化 | 声道0(左) | 声道0(左) | 声道1(右) | 声道1(右) | 148 | | (低位字节) | (高位字节) | (低位字节) | (高位字节) | 149 --------------------------------------------------------------------- 150 151 */ 152 class DataBlock 153 { 154 public: 155 void ReadData(ifstream &infile,int BitsPerSample)//BitsPerSample:1 8bit;2 16bit 156 { 157 int i=0; 158 159 bool un_find_data=true; 160 while(un_find_data) 161 { 162 infile.read((char*)&temp,1); 163 if(temp=='d') 164 { 165 infile.read((char*)&temp,1); 166 if(temp=='a') 167 { 168 infile.read((char*)&temp,1); 169 if(temp=='t') 170 { 171 infile.read((char*)&temp,1); 172 if(temp=='a') 173 { 174 un_find_data=false; 175 } 176 } 177 } 178 179 } 180 } 181 182 infile.read((char*)&m_DataSize,4); 183 m_NumSamples=m_DataSize/BitsPerSample; 184 if(BitsPerSample==1) 185 { 186 m_Data8=new char[m_NumSamples]; 187 for(i=0;i<m_NumSamples;i++) 188 { 189 infile.read((char*)&m_Data8[i],BitsPerSample); 190 } 191 } 192 else if(BitsPerSample==2) 193 { 194 m_Data16=new short[m_NumSamples]; 195 for(i=0;i<m_NumSamples;i++) 196 { 197 infile.read((char*)&m_Data16[i],BitsPerSample); 198 } 199 } 200 201 202 } 203 204 short *m_Data16; 205 char *m_Data8; 206 207 unsigned char temp; 208 unsigned char m_DataID[4]; 209 unsigned long m_DataSize; 210 211 212 int m_NumSamples;//样本数量 213 }; 214 class WaveFile 215 { 216 public: 217 void readwav(char *path) 218 { 219 ifstream infile(path,ios::binary); 220 m_Riff = new RiffBlock(); 221 m_Fmt = new FmtBlock(); 222 m_Data = new DataBlock(); 223 224 m_Riff->ReadRiff(infile); 225 m_Fmt->ReadFmt(infile); 226 m_Data->ReadData(infile,m_Fmt->BitsPerSample()); 227 int i=0; 228 data=new int[m_Data->m_DataSize/m_Fmt->BitsPerSample()]; 229 for(i=0;i<(m_Data->m_DataSize)/(m_Fmt->BitsPerSample());i++) 230 { 231 232 if(m_Fmt->BitsPerSample()==1) 233 { 234 data[i]=(int)m_Data->m_Data8[i]; 235 } 236 else if(m_Fmt->BitsPerSample()==2) 237 { 238 data[i]=(int)m_Data->m_Data16[i]; 239 } 240 } 241 242 } 243 244 245 void output_WAVfile_info(void)//test 246 { 247 cout<<"Audio Msg:"<<endl; 248 /* 249 RIFF WAVE Chunk Message 250 */ 251 cout<<m_Riff->m_RiffID<<endl; 252 cout<<m_Riff->m_RiffSize<<endl; 253 cout<<m_Riff->Format<<endl; 254 255 /* 256 Fmt Message 257 */ 258 cout<<m_Fmt->m_FmtID<<endl; 259 cout<<m_Fmt->m_FmtSize<<endl; 260 cout<<m_Fmt->m_FmtTag<<endl; 261 cout<<m_Fmt->m_Channels<<endl; 262 cout<<m_Fmt->m_SamplesPerSec<<endl; 263 cout<<m_Fmt->m_AverageBytesPerSec<<endl; 264 cout<<m_Fmt->m_BlockAlign<<endl; 265 cout<<m_Fmt->m_BitsPerSample<<endl; 266 cout<<m_Fmt->m_OtherMeg<<endl; 267 /* 268 Data Chunk Message 269 */ 270 cout<<m_Data->temp<<endl; 271 cout<<m_Data->m_DataID<<endl; 272 cout<<m_Data->m_DataSize<<endl; 273 274 } 275 int size(void)//音频长度 276 { 277 return m_Data->m_DataSize; 278 } 279 int channels(void) 280 { 281 return m_Fmt->m_Channels; 282 } 283 int bit(void) 284 { 285 return m_Fmt->BitsPerSample(); 286 } 287 int *data; 288 private: 289 RiffBlock *m_Riff; 290 FmtBlock *m_Fmt; 291 DataBlock *m_Data; 292 }; 293 } 294 295 #endif
编译时运行如下命令：
1 g++ -o out main.cpp -O2 -lm -lpthread -L/usr/X11R6/lib -lm -lpthread -lX11
结果：