stm32h743_player/User/audio/audio_mp3.c

#include "audio_mp3.h"
#include "main.h"
#include "ff.h"
#include "FreeRTOS.h"
#include "queue.h"
#include "elog.h"
#include "heap.h"
#include "bsp_aic3204.h"
#include "dr_mp3.h"

const static char *TAG = "player_mp3";

static size_t mp3_read(void* pUserData, void* pBufferOut, size_t bytesToRead)
{
  UINT br;
  FRESULT f_result = f_read(pUserData, pBufferOut, bytesToRead, &br); //从文件中读取新的内容

  HAL_GPIO_TogglePin(LED_Y_GPIO_Port, LED_Y_Pin);

  if (f_result != FR_OK) {
    elog_error(TAG, "file read error");
    return 0;
  }

  return br;
}

static drmp3_bool32 mp3_seek(void* pUserData, int offset, drmp3_seek_origin origin)
{
  FIL *file = (FIL*)pUserData;
  uint32_t fptr = f_tell(file);
  uint32_t fsize = f_size(file);

  HAL_GPIO_TogglePin(LED_G_GPIO_Port, LED_G_Pin);

  switch (origin) {
  case drmp3_seek_origin_start:
    if (offset < fsize) { //未超过文件末尾
      f_lseek(file, offset);
      return DRMP3_TRUE;
    } else {
      elog_warn(TAG, "flac_seek: seeking beyond the end of the file");
      return DRMP3_FALSE;
    }
  case drmp3_seek_origin_current:
    if (fptr + offset < fsize) { //未超过文件末尾
      f_lseek(file, fptr + offset);
      return DRMP3_TRUE;
    } else {
      elog_warn(TAG, "flac_seek: seeking beyond the end of the file");
      return DRMP3_FALSE;
    }

  default:
    elog_warn(TAG, "flac_seek: unimplemented seek origin type: %d", origin);
    return DRMP3_FALSE;
  }
}


static void* mp3_malloc(size_t sz, void* pUserData)
{
  UNUSED(pUserData);

  if (sz == 0) {
    return NULL;
  }

  void *ptr = malloc(sz);

  tlsf_pool_statistics *axi_heap_statistics = get_axi_heap_statistics();
  tlsf_pool_statistics *ahb_heap_statistics = get_ahb_heap_statistics();
  elog_debug(TAG, "mp3_malloc: allocated %d bytes memory @%p, free memory: AXI %d bytes, AHB %d bytes",
                  sz, ptr, axi_heap_statistics->free_size, ahb_heap_statistics->free_size);

  if (ptr == NULL) {
    elog_error(TAG, "mp3_malloc: error while allocating %d bytes of memory", sz);
  }

  return ptr;
}

static void* mp3_realloc(void* p, size_t sz, void* pUserData)
{
  UNUSED(pUserData);

  void *ptr = realloc(p, sz);

  tlsf_pool_statistics *axi_heap_statistics = get_axi_heap_statistics();
  tlsf_pool_statistics *ahb_heap_statistics = get_ahb_heap_statistics();
  elog_debug(TAG, "mp3_realloc: allocated %d bytes new memory @%p, free memory: AXI %d bytes, AHB %d bytes",
                  sz, ptr, axi_heap_statistics->free_size, ahb_heap_statistics->free_size);

  if (ptr == NULL) {
    elog_error(TAG, "mp3_realloc: error while allocating %d bytes of new memory", sz);
  }

  return ptr;
}

static void mp3_free(void* p, void* pUserData)
{
  UNUSED(pUserData);

  if (p == NULL) {
    return;
  }

  tlsf_pool_statistics *axi_heap_statistics = get_axi_heap_statistics();
  tlsf_pool_statistics *ahb_heap_statistics = get_ahb_heap_statistics();
  elog_debug(TAG, "mp3_free: memory freed @%p, free memory: AXI %d bytes, AHB %d bytes",
                  p, axi_heap_statistics->free_size, ahb_heap_statistics->free_size);

  free(p);
}

static const drmp3_allocation_callbacks mp3_allocation_cbs = {
  .onMalloc = mp3_malloc,
  .onFree = mp3_free,
  .onRealloc = mp3_realloc,
  .pUserData = NULL
};

void music_mp3_play(const char *file_name)
{
  FIL *file = malloc(sizeof(FIL));
  if (file == NULL) {
    elog_error(TAG, "music_mp3_play: error while allocating file object");
    return;
  }

  FRESULT f_result = f_open(file, file_name, FA_READ);
  if (f_result == FR_OK) {
    elog_info(TAG, "music_mp3_play: successfully opened %s for playing", file_name);
  } else {
    elog_error(TAG, "music_mp3_play: error while opening %s, error code=%d", file_name, f_result);
    free(file);
    return;
  }

  drmp3 mp3;
  drmp3_init(&mp3, mp3_read, mp3_seek, file, &mp3_allocation_cbs); //创建并初始化MP3解码器

  elog_info(TAG, "music_mp3_play: channels=%d, sampleRate=%d", mp3.channels, mp3.sampleRate);

  /* TODO: 判断mp3文件参数并返回错误 */

  bsp_aic3204_set_fs(&hi2c1, mp3.sampleRate); //设置采样率

  audio_hal_start(DRMP3_MAX_SAMPLES_PER_FRAME, sizeof(drmp3_int16)); //初始化SAI

  while(1) {
    drmp3_int16 *pcm_sample = malloc(DRMP3_MAX_SAMPLES_PER_FRAME * sizeof(drmp3_int16));
    if (pcm_sample == NULL) {
      elog_error(TAG, "music_mp3_play: sample buffer allocation failed, size=%d bytes", DRMP3_MAX_SAMPLES_PER_FRAME * sizeof(drmp3_int16));
      break;
    }

    /* 此处的framesToRead指的是PCM块中采样的数量(可以理解为时间层面的采样数) 不考虑声道数量与每个采样的字节数 */
    uint32_t sample_count = drmp3_read_pcm_frames_s16(&mp3, DRMP3_MAX_PCM_FRAMES_PER_MP3_FRAME, pcm_sample); //解码新一帧MP3数据

    if (sample_count != 0) {
      audio_hal_write(pcm_sample, DRMP3_MAX_SAMPLES_PER_FRAME * sizeof(drmp3_int16)); //将解码后的PCM数据写入SAI
    } else {
      free(pcm_sample);
      elog_info(TAG, "play done");
      break; //结束播放
    }

    if (HAL_GPIO_ReadPin(KEY2_GPIO_Port, KEY2_Pin) == GPIO_PIN_RESET) {
      vTaskDelay(pdMS_TO_TICKS(100));
      while (HAL_GPIO_ReadPin(KEY2_GPIO_Port, KEY2_Pin) == GPIO_PIN_RESET) {
        vTaskDelay(pdMS_TO_TICKS(1));
      }
      break;
    }
  }

  audio_hal_stop(); //停止SAI播放

  if (file != NULL) {
    f_close(file); //关闭文件
    free(file);
  }

  drmp3_uninit(&mp3); //释放解码器内部申请的文件缓冲区
}