文件操作到QByteArray操作？

Question

我有以下代码将原始音频文件转换为wav文件：

int MainWindow::rawToWav(const char *rawfn, const char *wavfn, long samplingRate)
{
    long chunksize=0x10;
    int statusCollect = 0;
    struct
    {
        unsigned short    wFormatTag;
        unsigned short    wChannels;
        unsigned long     dwSamplesPerSec;
        unsigned long     dwAvgBytesPerSec;
        unsigned short    wBlockAlign;
        unsigned short    wBitsPerSample;
    } fmt;

    errno_t err;
    FILE *raw;
    err = fopen_s(&raw, rawfn, "rb");
    if(!raw)
        return -2;

    fseek(raw, 0, SEEK_END);
    long bytes = ftell(raw);
    fseek(raw, 0, SEEK_SET);

    long samplecount = bytes/2;
    long riffsize    = samplecount*2+0x24;
    long datasize    = samplecount*2;

    FILE *wav;
    err = fopen_s(&wav, wavfn, "wb");
    if(!wav)
    {
        fclose(raw);
        return -3;
    }

    fwrite( "RIFF",     1, 4, wav );
    fwrite( &riffsize,  4, 1, wav );
    fwrite( "WAVEfmt ", 1, 8, wav );
    fwrite( &chunksize, 4, 1, wav );

    int bitsPerSample = 16;
    int bytesPerSample = bitsPerSample/8;
    int channel = 2;

    fmt.wFormatTag = 1;      // PCM
    fmt.wChannels  = channel;      // MONO
    fmt.dwSamplesPerSec  = samplingRate;
    fmt.dwAvgBytesPerSec = samplingRate*channel*bytesPerSample; // 16 bit
    fmt.wBlockAlign      = channel*bytesPerSample;
    fmt.wBitsPerSample   = bitsPerSample;

    fwrite( &fmt,      sizeof(fmt), 1, wav );
    fwrite( "data",    1,           4, wav );
    fwrite( &datasize, 4,           1, wav );
    short buff[1024];
    while( !feof(raw) )
    {
        int cnt=fread(buff,2,1024,raw);
        if( cnt == 0 )
            break;
        fwrite(buff,2,cnt,wav);
    }
    statusCollect = fclose( raw );
    statusCollect += fclose( wav );
    return statusCollect;
}

我想要的操作完全相同，不是对文件类型的数据，而是对QByteArray类型。

所以我正在尝试下面的方法。首先，我尝试在QByteArray对象上添加wav头。然后我将原始音频文件上传到程序中。然后我将原始数据添加到我已经添加了wav头的QByteArray对象中。然后将QByteArray保存为wav文件。

void MainWindow::rawToWavQT(QByteArray* arr, long samplingRate, long sizeOfRawFile)
{
    long chunksize=0x10;
    struct
    {
        unsigned short    wFormatTag;
        unsigned short    wChannels;
        unsigned long     dwSamplesPerSec;
        unsigned long     dwAvgBytesPerSec;
        unsigned short    wBlockAlign;
        unsigned short    wBitsPerSample;
    } fmt;

    long samplecount = sizeOfRawFile/2;
    long riffsize    = samplecount*2+0x24;
    long datasize    = samplecount*2;

    arr->append("RIFF");//    fwrite( "RIFF",     1, 4, wav );
    arr->append((const char*)&riffsize);//    fwrite( &riffsize,  4, 1, wav );
    arr->append("WAVEfmt ");//    fwrite( "WAVEfmt ", 1, 8, wav );
    arr->append((const char*)&chunksize);//    fwrite( &chunksize, 4, 1, wav );

    int bitsPerSample = 16;
    int bytesPerSample = bitsPerSample/8;
    int channel = 2;

    fmt.wFormatTag = 1;      // PCM
    fmt.wChannels  = channel;      // MONO
    fmt.dwSamplesPerSec  = samplingRate;
    fmt.dwAvgBytesPerSec = samplingRate*channel*bytesPerSample; // 16 bit
    fmt.wBlockAlign      = channel*bytesPerSample;
    fmt.wBitsPerSample   = bitsPerSample;

    arr->append((const char*)&fmt);//    fwrite( &fmt,      sizeof(fmt), 1, wav );
    arr->append("data");//    fwrite( "data",    1,           4, wav );
    arr->append((const char*)&datasize);//    fwrite( &datasize, 4,           1, wav );
}

但是这种将头添加到QByteArray中然后添加原始数据的方式并不能产生正确类型的wav文件，因为它无法播放。您认为从第二个函数中判断我做了什么错误?在第二个函数中，我所做的操作与对第一个函数的操作相同，但对QByteArray对象而不是对文件对象？

谢谢。

Answer 1

您的数据连接函数只需在第一个空字节处停止，就会丢失重要数据并破坏对齐。相反，您希望以类似于fwrite的方式指定要附加的长度。解决方案:将append()语句从单个const char *参数替换为使用数据和数据长度构造的QByteArray语句。

变化

arr->append((const char*)&riffsize);

至

arr->append(QByteArray((const char*)&riffsize, 4));

同样，对于其他原始数据，append语句也是如此。