esp32使用fft算法显示音乐频谱

void FFT_Task(void *arg)
{
  static int8_t i2s_readraw_buff[1024];
  size_t bytesread;
  int16_t *buffptr;
  int16_t *samples_sc16 = (int16_t *)i2s_readraw_buff;
  float *samples_fc32 = (float *)calloc(SAMPLES_NUM, sizeof(float));
  double data = 0;
  i2s_init();
  while (1)
  {
    if (fft_en == 1)
    {
      i2s_read(I2S_NUM_0, (char *)i2s_readraw_buff, SAMPLES_NUM * 2, &bytesread, (100 / portTICK_RATE_MS));
      fft_config_t *real_fft_plan = fft_init(512, FFT_REAL, FFT_FORWARD, NULL, NULL);
      buffptr = (int16_t *)i2s_readraw_buff;
      for (uint16_t count_n = 0; count_n < real_fft_plan->size; count_n++)
      {
        real_fft_plan->input[count_n] = (float)map(buffptr[count_n], INT16_MIN, INT16_MAX, -1000, 1000);
      }
      fft_execute(real_fft_plan);
      for (uint16_t count_n = 1; count_n < CANVAS_HEIGHT; count_n++)
      {
        data = sqrt(real_fft_plan->output[2 * count_n] * real_fft_plan->output[2 * count_n] + real_fft_plan->output[2 * count_n + 1] * real_fft_plan->output[2 * count_n + 1]);
        fft_dis_buff[CANVAS_HEIGHT - count_n] = map(data, 0, 2000, 0, CANVAS_HEIGHT);
      }
      fft_destroy(real_fft_plan);
      for (uint16_t count_y = 0; count_y < CANVAS_HEIGHT;)
      {
        lv_chart_set_next(chart_fft, series_fft, fft_dis_buff[count_y]);
        count_y += 5;
      }
    }
    else
    {
      i2s_driver_uninstall(I2S_NUM_0);
      vTaskDelete(NULL);
    }
  }
}