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
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：
时间： 2024-10-26 22:24:51