C++ odczyt części danych pliku WAV

Question

C++ odczyt części danych pliku WAV

Planuję stworzyć program, który wizualizuje przebieg dźwięku a .plik wav.

Do tej pory zacząłem od poprawnego odczytania części nagłówka wspomnianego pliku wav. Kod, którego używam będzie taki:

#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;
}

Próbowałem go kilka razy i dane, które daje wydaje się spójne przez różne pliki wav w folderze Media w folderze Windows.

Następnym krokiem będzie zapisanie rzeczywistych danych pliku wav w wektorze. Jednak nie mam pojęcia, jak żeby to zrobić. Rozwiązania Online, które znalazłem, posunęły się tylko do odczytu pliku nagłówkowego.

Jakieś pomysły jak przechowywać (i mam nadzieję wyświetlać) rzeczywiste dane pliku wav? Dzięki!

11

c++wav

Author: Razgriz, 2012-12-01

Source

2 answers

Wiem, że to stary post, ale twoje parametry fread są przełączane, tutaj jest bardziej poprawna wersja (wymaga g++-4.7 lub wyższej z flagą-std=c++11 jak ta " g++ - std = c++11 WaveReader.cpp-o WaveReader").

#include <iostream>
#include <string>
#include <fstream>
#include <cstdint>

using std::cin;
using std::cout;
using std::endl;
using std::fstream;
using std::string;

typedef struct  WAV_HEADER
{
    /* RIFF Chunk Descriptor */
    uint8_t         RIFF[4];        // RIFF Header Magic header
    uint32_t        ChunkSize;      // RIFF Chunk Size
    uint8_t         WAVE[4];        // WAVE Header
    /* "fmt" sub-chunk */
    uint8_t         fmt[4];         // FMT header
    uint32_t        Subchunk1Size;  // Size of the fmt chunk
    uint16_t        AudioFormat;    // Audio format 1=PCM,6=mulaw,7=alaw,     257=IBM Mu-Law, 258=IBM A-Law, 259=ADPCM
    uint16_t        NumOfChan;      // Number of channels 1=Mono 2=Sterio
    uint32_t        SamplesPerSec;  // Sampling Frequency in Hz
    uint32_t        bytesPerSec;    // bytes per second
    uint16_t        blockAlign;     // 2=16-bit mono, 4=16-bit stereo
    uint16_t        bitsPerSample;  // Number of bits per sample
    /* "data" sub-chunk */
    uint8_t         Subchunk2ID[4]; // "data"  string
    uint32_t        Subchunk2Size;  // Sampled data length
} wav_hdr;

// Function prototypes
int getFileSize(FILE* inFile);

int main(int argc, char* argv[])
{
    wav_hdr wavHeader;
    int headerSize = sizeof(wav_hdr), filelength = 0;

    const char* filePath;
    string input;
    if (argc <= 1)
    {
        cout << "Input wave file name: ";
        cin >> input;
        cin.get();
        filePath = input.c_str();
    }
    else
    {
        filePath = argv[1];
        cout << "Input wave file name: " << filePath << endl;
    }

    FILE* wavFile = fopen(filePath, "r");
    if (wavFile == nullptr)
    {
        fprintf(stderr, "Unable to open wave file: %s\n", filePath);
        return 1;
    }

    //Read the header
    size_t bytesRead = fread(&wavHeader, 1, headerSize, wavFile);
    cout << "Header Read " << bytesRead << " bytes." << endl;
    if (bytesRead > 0)
    {
        //Read the data
        uint16_t bytesPerSample = wavHeader.bitsPerSample / 8;      //Number     of bytes per sample
        uint64_t numSamples = wavHeader.ChunkSize / bytesPerSample; //How many samples are in the wav file?
        static const uint16_t BUFFER_SIZE = 4096;
        int8_t* buffer = new int8_t[BUFFER_SIZE];
        while ((bytesRead = fread(buffer, sizeof buffer[0], BUFFER_SIZE / (sizeof buffer[0]), wavFile)) > 0)
        {
            /** DO SOMETHING WITH THE WAVE DATA HERE **/
            cout << "Read " << bytesRead << " bytes." << endl;
        }
        delete [] buffer;
        buffer = nullptr;
        filelength = getFileSize(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 from 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;
    }
    fclose(wavFile);
    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;
}

7

Author: kory,
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2015-08-20 20:45:18

score 12 · Accepted Answer

To zdjęcie pochodzi z kursu Stanforda

Format pliku WAV

Więc możesz zobaczyć, że dane audio pojawiają się natychmiast po nagłówkach, które już przeczytałeś i będą Subchunk2Size bajty danych audio.

Pseudokod dla tego to

ReadRIFF();
ReadFMT();
int32 chunk2Id = Read32(BigEndian);
int32 chunk2Size = Read32(LittleEndian);
for (int i = 0; i < chunk2Size; i++)
{
    audioData[i] = ReadByte();
}

Jeśli dźwięk jest stereo, będziesz miał dwa strumienie audio w data. Jeśli dźwięk jest skompresowany (mp3, aac, itp.), będziesz musiał najpierw go dekompresować.