优化这段代码uint8_t *audio_buffer = (uint8_t *)calloc(1, AUDIO_BUFFER_SIZE); assert(audio_buffer); size_t r_bytes = 0; size_t w_bytes = 0; uint8_t volume = 1; FILE *f_read_audio = fopen("/sdcard/wav/bell/CueTone.WAV", "rb"); if (f_read_audio == NULL) { ESP_LOGI(TAG, "Failed to open file"); } else { while (1) { r_bytes = fread(audio_buffer, 1, AUDIO_BUFFER_SIZE, f_read_audio); if (r_bytes == 0) { ESP_LOGI(TAG, "i2s_task will delete"); break; } ESP_LOGI(TAG, ":read %s bytes\n", audio_buffer); // 调整音量大小 int16_t *pcmdata = (int16_t *)audio_buffer; for (int i = 0; i < r_bytes / 2; i++) { int32_t temp = (int32_t)(*pcmdata); temp = temp * volume; temp = temp / 10; *pcmdata = (int16_t)temp; pcmdata++; } // for (int i = 0; i < r_bytes; i += 2) // { // audio_buffer[i] = audio_buffer[i + 1]; // audio_buffer[i + 1] = audio_buffer[i]; // } /* Write i2s data */ if (i2s_channel_write(tx_chan, audio_buffer, AUDIO_BUFFER_SIZE, &w_bytes, portMAX_DELAY) == ESP_OK) { ESP_LOGI(TAG, "Write Task: i2s write %d bytes\n", w_bytes); } else { ESP_LOGI(TAG, "Write Task: i2s write failed\n"); } } }

这段代码需要做以下优化：

1. 避免使用动态内存分配函数 calloc，因为它会频繁调用 malloc 和 free 函数，影响性能，可以使用静态分配的数组代替。

2. 避免在循环中频繁调用 fread 函数，可以将文件读取到缓存中，然后再从缓存中读取数据。

3. 避免在循环中频繁调用 i2s_channel_write 函数，可以将数据写入缓存中，然后再从缓存中写入 i2s 通道。

4. 调整音量大小时可以使用移位运算代替除法运算，提高性能。

下面是优化后的代码：

#define AUDIO_BUFFER_SIZE 2048

uint8_t audio_buffer[AUDIO_BUFFER_SIZE];
size_t r_bytes = 0;
size_t w_bytes = 0;
uint8_t volume = 10;

FILE *f_read_audio = fopen("/sdcard/wav/bell/CueTone.WAV", "rb");
if (f_read_audio == NULL)
{
    ESP_LOGI(TAG, "Failed to open file");
}
else
{
    // 读取整个文件到缓存中
    fseek(f_read_audio, 0, SEEK_END);
    size_t file_size = ftell(f_read_audio);
    fseek(f_read_audio, 0, SEEK_SET);
    size_t read_size = fread(audio_buffer, 1, file_size, f_read_audio);
    fclose(f_read_audio);

    int16_t *pcmdata = (int16_t *)audio_buffer;
    for (int i = 0; i < read_size / 2; i++)
    {
        int32_t temp = (int32_t)(*pcmdata);
        temp = (temp * volume) >> 3; // 移位运算代替除法运算
        *pcmdata = (int16_t)temp;
        pcmdata++;
    }

    // 将数据写入 i2s 缓存中
    int offset = 0;
    while (offset < read_size)
    {
        size_t write_size = MIN(read_size - offset, AUDIO_BUFFER_SIZE);
        memcpy(audio_buffer, audio_buffer + offset, write_size);

        if (i2s_channel_write(tx_chan, audio_buffer, write_size, &w_bytes, portMAX_DELAY) == ESP_OK)
        {
            ESP_LOGI(TAG, "Write Task: i2s write %d bytes\n", w_bytes);
        }
        else
        {
            ESP_LOGI(TAG, "Write Task: i2s write failed\n");
        }

        offset += write_size;
    }
}