把音频数据保存 wav文件， save audio data to wav file

/* this play_buffer holds the digitized audio */

//unsigned char buf[LENGTH*RATE*SIZE*CHANNELS/8];

typedef unsigned char   BYTE;

typedef unsigned short  WORD;

typedef unsigned int  DWORD;

typedef unsigned int  FOURCC;    /* a four character code */

/* flags for 'wFormatTag' field of WAVEFORMAT */

#define WAVE_FORMAT_PCM 1

/* MMIO macros */

#define mmioFOURCC(ch0, ch1, ch2, ch3) /

  ((DWORD)(BYTE)(ch0) | ((DWORD)(BYTE)(ch1) << 8) | /

  ((DWORD)(BYTE)(ch2) << 16) | ((DWORD)(BYTE)(ch3) << 24))

#define FOURCC_RIFF    mmioFOURCC ('R', 'I', 'F', 'F')

#define FOURCC_LIST    mmioFOURCC ('L', 'I', 'S', 'T')

#define FOURCC_WAVE    mmioFOURCC ('W', 'A', 'V', 'E')

#define FOURCC_FMT    mmioFOURCC ('f', 'm', 't', ' ')

#define FOURCC_DATA    mmioFOURCC ('d', 'a', 't', 'a')

typedef struct CHUNKHDR {

    FOURCC ckid;        /* chunk ID */

    DWORD dwSize;             /* chunk size */

} CHUNKHDR;

/* simplified Header for standard WAV files */

typedef struct WAVEHDR {

    CHUNKHDR chkRiff;

    FOURCC fccWave;

    CHUNKHDR chkFmt;

    WORD wFormatTag;       /* format type */

    WORD nChannels;       /* number of channels (i.e. mono, stereo, etc.) */

    DWORD nSamplesPerSec;  /* sample rate */

    DWORD nAvgBytesPerSec; /* for play_buffer estimation */

    WORD nBlockAlign;       /* block size of data */

    WORD wBitsPerSample;

    CHUNKHDR chkData;

} WAVEHDR;

#if BYTE_ORDER == BIG_ENDIAN

# define cpu_to_le32(x) SWAP4((x))

# define cpu_to_le16(x) SWAP2((x))

# define le32_to_cpu(x) SWAP4((x))

# define le16_to_cpu(x) SWAP2((x))

#else

# define cpu_to_le32(x) (x)

# define cpu_to_le16(x) (x)

# define le32_to_cpu(x) (x)

# define le16_to_cpu(x) (x)

#endif

static void wav_init_header(WAVEHDR *fileheader)

{

    /* stolen from cdda2wav */

    int nBitsPerSample = 16;

    int channels       = 1;

    int rate           = 8000;

    unsigned long nBlockAlign = channels * ((nBitsPerSample + 7) / 8);

    unsigned long nAvgBytesPerSec = nBlockAlign * rate;

    unsigned long temp = /* data length */ 0 +

    sizeof(WAVEHDR) - sizeof(CHUNKHDR);

    fileheader->chkRiff.ckid    = cpu_to_le32(FOURCC_RIFF);

    fileheader->fccWave         = cpu_to_le32(FOURCC_WAVE);

    fileheader->chkFmt.ckid     = cpu_to_le32(FOURCC_FMT);

    fileheader->chkFmt.dwSize   = cpu_to_le32(16);

    fileheader->wFormatTag      = cpu_to_le16(WAVE_FORMAT_PCM);

    fileheader->nChannels       = cpu_to_le16(channels);

    fileheader->nSamplesPerSec  = cpu_to_le32(rate);

    fileheader->nAvgBytesPerSec = cpu_to_le32(nAvgBytesPerSec);

    fileheader->nBlockAlign     = cpu_to_le16(nBlockAlign);

    fileheader->wBitsPerSample  = cpu_to_le16(nBitsPerSample);

    fileheader->chkData.ckid    = cpu_to_le32(FOURCC_DATA);

    fileheader->chkRiff.dwSize  = cpu_to_le32(temp);

    fileheader->chkData.dwSize  = cpu_to_le32(0 /* data length */);

}

static void wav_start_write(FILE* fd, WAVEHDR *fileheader)

{

    wav_init_header(fileheader);

    fwrite(fileheader,1, sizeof(WAVEHDR), fd);

}

static void wav_stop_write(FILE* fd, WAVEHDR *fileheader, int wav_size)

{

    unsigned long temp = wav_size + sizeof(WAVEHDR) - sizeof(CHUNKHDR);

    fileheader->chkRiff.dwSize = cpu_to_le32(temp);

    fileheader->chkData.dwSize = cpu_to_le32(wav_size);

    fseek(fd,0,SEEK_SET);

       fwrite(fileheader,1, sizeof(WAVEHDR), fd);

}