[C++]I want to get PCM data from wav file

Question

I know the Wave file's structure. But I don't know the exact structure of PCM DATA.

#include<iostream>
#include<fstream>
using namespace std;

struct WAVE_HEADER{
    char Chunk[4];
    int ChunkSize;
    char format[4];
    char Sub_chunk1ID[4];
    int Sub_chunk1Size;
    short int AudioFormat;
    short int NumChannels;
    int SampleRate;
    int ByteRate;
    short int BlockAlign;
    short int BitsPerSample;
    char Sub_chunk2ID[4];
    int Sub_chunk2Size;
};

struct WAVE_HEADER waveheader;

int main(){
    FILE *sound;
    sound = fopen("music.wav","rb");
    short D;
    fread(&waveheader,sizeof(waveheader),1,sound);
    cout << "BitsPerSample : "  << waveheader.BitsPerSample << endl;
    while(!feof(sound)){
        fread(&D,sizeof(waveheader.BitsPerSample),1,sound);
        cout << int(D) << endl;
    }
}

The above code is what I made so far. Also, this code can read header exactly. But I don't know if this can read PCM data part precisely. Is there any reference of PCM data structure? I couldn't find it.

"music.wav" has 16 bits per sample, 16 byte rate, stereo channal and two blockAlign. How should the above be changed?

PCM has no structure. The raw samples follow each other as 8, 16, 24 or 32 bit signed or unsigned integers (or, less frequently, as floats or doubles.) — The Paramagnetic Croissant

SleuthEye SleuthEye · Accepted Answer · 2015-06-04T15:03:06

As indicated in this description of wav specifications, PCM data are stored using little-endian byte order and two's-complement for resolutions greater than 8 bit per sample. In other words, on an Intel processor, 16-bit samples typically corresponds to signed short. Additionally, for stereo channels the data is interleaved (left/right samples).

With that in mind, assuming "music.wav" does indeed contain 16-bit PCM samples and you are reading the data on a little-endian platform using a compiler where sizeof(short)==2, then the code you posted should read the samples correctly.

[C++]I want to get PCM data from wav file

1 Answers