将原始PCM转换为FLAC

EDIT:我已经更新了下面的代码，以类似于我所取得的进展。我试着自己写.wav头。代码现在不能正常工作，音频没有被正确地写入文件。该代码还不包含任何将其转换为.flac文件的尝试。

我使用树莓派(Debian Linux)用ALSA库录制音频。录音工作正常，但我需要将输入音频编码为FLAC编解码器。

这就是我迷路的地方。我花了相当多的时间试图弄清楚如何将这些原始数据转换为FLAC，但我不断提出如何将.wav文件转换为.flac文件的示例。

这是当前的(更新)代码，我有记录音频与ALSA(它可能有点粗糙，我仍然拿起c++):

// Use the newer ALSA API
#define ALSA_PCM_NEW_HW_PARAMS_API
#include <alsa/asoundlib.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct Riff
{
  char chunkId[4]; // "RIFF" (assuming char is 8 bits)
  int chunkSize; // (assuming int is 32 bits)
  char format[4]; // "WAVE"
};
struct Format
{
  char chunkId[4]; // "fmt "
  int chunkSize;
  short format; // assuming short is 16 bits
  short numChannels;
  int sampleRate;
  int byteRate;
  short align;
  short bitsPerSample;
};
struct Data
{
  char chunkId[4]; // "data"
  int chunkSize; // length of data
  char* data;
};
struct Wave // Actual structure of a PCM WAVE file
{
  Riff riffHeader;
  Format formatHeader;
  Data dataHeader;
};
int main(int argc, char *argv[])
{
        void saveWaveFile(struct Wave *waveFile);
        long loops;
        int rc;
        int size;
        snd_pcm_t *handle;
        snd_pcm_hw_params_t *params;
        unsigned int sampleRate = 44100;
        int dir;
        snd_pcm_uframes_t frames;
        char *buffer;
        char *device = (char*) "plughw:1,0";
        //char *device = (char*) "default";
        printf("Capture device is %sn", device);
        /* Open PCM device for recording (capture). */
        rc = snd_pcm_open(&handle, device, SND_PCM_STREAM_CAPTURE, 0);
        if (rc < 0)
        {
                fprintf(stderr, "Unable to open PCM device: %sn", snd_strerror(rc));
                exit(1);
        }
        /* Allocate a hardware parameters object. */
        snd_pcm_hw_params_alloca(&params);
        /* Fill it in with default values. */
        snd_pcm_hw_params_any(handle, params);
        /* Set the desired hardware parameters. */
        /* Interleaved mode */
        snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);
        /* Signed 16-bit little-endian format */
        snd_pcm_hw_params_set_format(handle, params, SND_PCM_FORMAT_S16_LE);
        /* Two channels (stereo) */
        snd_pcm_hw_params_set_channels(handle, params, 2);
        /* 44100 bits/second sampling rate (CD quality) */
        snd_pcm_hw_params_set_rate_near(handle, params, &sampleRate, &dir);
        /* Set period size to 32 frames. */
        frames = 32;
        snd_pcm_hw_params_set_period_size_near(handle, params, &frames, &dir);
        /* Write the parameters to the driver */
        rc = snd_pcm_hw_params(handle, params);
        if (rc < 0)
        {
                fprintf(stderr, "Unable to set HW parameters: %sn", snd_strerror(rc));
                exit(1);
        }
        /* Use a buffer large enough to hold one period */
        snd_pcm_hw_params_get_period_size(params, &frames, &dir);
        size = frames * 4; /* 2 bytes/sample, 2 channels */
        buffer = (char *) malloc(size);
        /* We want to loop for 5 seconds */
        snd_pcm_hw_params_get_period_time(params, &sampleRate, &dir);
        loops = 5000000 / sampleRate;
        while (loops > 0)
        {
                loops--;
                rc = snd_pcm_readi(handle, buffer, frames);
                if (rc == -EPIPE)
                {
                        /* EPIPE means overrun */
                        fprintf(stderr, "Overrun occurred.n");
                        snd_pcm_prepare(handle);
                } else if (rc < 0)
                {
                        fprintf(stderr, "Error from read: %sn", snd_strerror(rc));
                } else if (rc != (int)frames)
                {
                        fprintf(stderr, "Short read, read %d frames.n", rc);
                }
                if (rc != size) fprintf(stderr, "Short write: wrote %d bytes.n", rc);
        }
        Wave wave;
        strcpy(wave.riffHeader.chunkId, "RIFF");
        wave.riffHeader.chunkSize = 36 + size;
        strcpy(wave.riffHeader.format, "WAVE");
        strcpy(wave.formatHeader.chunkId, "fmt");
        wave.formatHeader.chunkSize = 16;
        wave.formatHeader.format = 1; // PCM, other value indicates compression
        wave.formatHeader.numChannels = 2; // Stereo
        wave.formatHeader.sampleRate = sampleRate;
        wave.formatHeader.byteRate = sampleRate * 2 * 2;
        wave.formatHeader.align = 2 * 2;
        wave.formatHeader.bitsPerSample = 16;
        strcpy(wave.dataHeader.chunkId, "data");
        wave.dataHeader.chunkSize = size;
        wave.dataHeader.data = buffer;
        saveWaveFile(&wave);
        snd_pcm_drain(handle);
        snd_pcm_close(handle);
        free(buffer);
        return 0;
}
void saveWaveFile(struct Wave *waveFile)
{
        FILE *file = fopen("test.wav", "wb");
        size_t written;
        if (file == NULL)
        {
                fprintf(stderr, "Cannot open file for writing.n");
                exit(1);
        }
        written = fwrite(waveFile, sizeof waveFile[0], 1, file);
        fclose(file);
        if (written < 1);
        {
                fprintf(stderr, "Writing to file failed, error %d.n", written);
                exit(1);
        }
}

我该如何将PCM数据转换为FLAC并将其保存到磁盘以供以后使用?我已经下载了libflac-dev，只需要一个例子去。

我现在做的方式:

./capture > test.raw     // or   ./capture > test.flac

应该是这样的(程序为我做了一切):

./capture