C ++读取WAV文件的Data部分 [英] C++ Reading the Data part of a WAV file
问题描述
我计划创建一个可视化.wav文件的音频波形的程序。
I plan to create a program that will visualize the audio waveform of a .wav file.
到目前为止，我已经开始通过正确地读取所述wav文件的头部分。我使用的代码是：
So far, I have started by properly reading the header part of the said wav file. The code I use would be this:
#include <iostream>
#include <string>
#include <fstream>
using namespace std;
using std::string;
using std::fstream;
typedef struct WAV_HEADER{
char RIFF[4]; // RIFF Header Magic header
unsigned long ChunkSize; // RIFF Chunk Size
char WAVE[4]; // WAVE Header
char fmt[4]; // FMT header
unsigned long Subchunk1Size; // Size of the fmt chunk
unsigned short AudioFormat; // Audio format 1=PCM,6=mulaw,7=alaw, 257=IBM Mu-Law, 258=IBM A-Law, 259=ADPCM
unsigned short NumOfChan; // Number of channels 1=Mono 2=Sterio
unsigned long SamplesPerSec; // Sampling Frequency in Hz
unsigned long bytesPerSec; // bytes per second
unsigned short blockAlign; // 2=16-bit mono, 4=16-bit stereo
unsigned short bitsPerSample; // Number of bits per sample
char Subchunk2ID[4]; // "data" string
unsigned long Subchunk2Size; // Sampled data length
}wav_hdr;
// Function prototypes
int getFileSize(FILE *inFile);
int main(int argc,char *argv[]){
wav_hdr wavHeader;
FILE *wavFile;
int headerSize = sizeof(wav_hdr),filelength = 0;
string answer;
do{
string input;
string answer;
const char* filePath;
cout << "Pick wav file from the Windows Media File: ";
cin >> input;
cin.get();
cout << endl;
path = "C:\\Windows\\Media\\" + input + ".wav";
filePath = path.c_str();
wavFile = fopen( filePath , "r" );
if(wavFile == NULL){
printf("Can not able to open wave file\n");
//exit(EXIT_FAILURE);
}
fread(&wavHeader,headerSize,1,wavFile);
filelength = getFileSize(wavFile);
fclose(wavFile);
cout << "File is :" << filelength << " bytes." << endl;
cout << "RIFF header :" << wavHeader.RIFF[0]
<< wavHeader.RIFF[1]
<< wavHeader.RIFF[2]
<< wavHeader.RIFF[3] << endl;
cout << "WAVE header :" << wavHeader.WAVE[0]
<< wavHeader.WAVE[1]
<< wavHeader.WAVE[2]
<< wavHeader.WAVE[3]
<< endl;
cout << "FMT :" << wavHeader.fmt[0]
<< wavHeader.fmt[1]
<< wavHeader.fmt[2]
<< wavHeader.fmt[3]
<< endl;
cout << "Data size :" << wavHeader.ChunkSize << endl;
// Display the sampling Rate form the header
cout << "Sampling Rate :" << wavHeader.SamplesPerSec << endl;
cout << "Number of bits used :" << wavHeader.bitsPerSample << endl;
cout << "Number of channels :" << wavHeader.NumOfChan << endl;
cout << "Number of bytes per second :" << wavHeader.bytesPerSec << endl;
cout << "Data length :" << wavHeader.Subchunk2Size << endl;
cout << "Audio Format :" << wavHeader.AudioFormat << endl;
// Audio format 1=PCM,6=mulaw,7=alaw, 257=IBM Mu-Law, 258=IBM A-Law, 259=ADPCM
cout << "Block align :" << wavHeader.blockAlign << endl;
cout << "Data string :" << wavHeader.Subchunk2ID[0]
<< wavHeader.Subchunk2ID[1]
<< wavHeader.Subchunk2ID[2]
<< wavHeader.Subchunk2ID[3]
<< endl;
cout << endl << endl << "Try something else? (y/n)";
cin >> answer;
//cin.get();
cout << endl << endl;
}while( answer == "y" );
getchar();
return 0;
}
// find the file size
int getFileSize(FILE *inFile){
int fileSize = 0;
fseek(inFile,0,SEEK_END);
fileSize=ftell(inFile);
fseek(inFile,0,SEEK_SET);
return fileSize;
}
我试过几次， wav文件在Windows文件夹中的Media文件夹中。
I've tried it several times and the data it gives seems consistent through different wav files in the Media folder in the Windows folder.
下一步是将wav文件的实际数据存储在向量中。但是，我对如何做到这一点很无能。我发现的在线解决方案只能读取头文件。
The next step then would be storing the actual data of the wav file in a vector. However, I'm quite clueless on how to do this. Online solutions that I found only went as far as reading the header file.
有关如何存储（并希望显示）wav文件的实际数据的任何想法？
感谢！
Any ideas on how to store (and hopefully display) the actual data of the wav file? Thanks!
推荐答案
因此，您可以看到音频数据紧接在您已经读取的标题之后， $ c> Subchunk2Size 字节的音频数据。
So you can see that the audio data occurs immediately after the headers you already read and there will be Subchunk2Size bytes of audio data.
这个伪代码是
ReadRIFF();
ReadFMT();
int32 chunk2Id = Read32(BigEndian);
int32 chunk2Size = Read32(LittleEndian);
for (int i = 0; i < chunk2Size; i++)
{
audioData[i] = ReadByte();
}
如果音频是立体声的，您将有两个音频流 data 。如果音频被压缩（mp3，aac等），你必须先解压缩它。
If the audio is stereo you'll have two audio streams in data. If the audio is compressed (mp3, aac, etc) you'll have to decompress it first.
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