The "GR-PEACH_Audio_Playback_Sample" is a sample code that can provides high-resolution audio playback of FLAC format files. It also allows the user to audio-playback control functions such as play, pause, and stop by manipulating key switches.

Dependencies:   R_BSP TLV320_RBSP USBHost_custom

Note

For a sample program of with LCD Board,
please refer to GR-PEACH_Audio_Playback_7InchLCD_Sample.

Introduction

The "GR-PEACH_Audio_Playback_Sample" is a sample code that can provides high-resolution audio playback of FLAC format files. It also allows the user to audio-playback control functions such as play, pause, and stop by manipulating key switches.

1. Overview of the Sample Code

1.1 Software Block Diagram

Figure 1.1 shows the software block diagram.

/media/uploads/dkato/audioplayback_figure1_1x.png

1.2 Pin Definitions

Table 1.1 shows the pins that this sample code are to use.

/media/uploads/dkato/audioplayback_table1_1.png

2. Sample Code Operating Environment

This sample code runs in GR-PEACH + the Audio/Camera shield for the GR-PEACH environment. This section explains the functions of the ports that are used by this sample code.

2.1 Operating Environment

Figure 2.1 shows the configuration of the operating environment for running this sample code.

/media/uploads/dkato/audioplayback_figure2_1.png /media/uploads/1050186/figure2_2.png /media/uploads/dkato/audioplayback_figure2_3.png

2.2 List of User Operations

A list of user operations on the command line, TFT touch keys, and switch key that the user can perform for this sample code is shown in. Table 2.1.

/media/uploads/dkato/audioplayback_table2_1x.png

3. Function Outline

The functions of this sample code are summarized in Table 3.1 to Table 3.3.

/media/uploads/dkato/audioplayback_table3_1.png /media/uploads/dkato/audioplayback_table3_2.png /media/uploads/dkato/audioplayback_table3_3.png /media/uploads/dkato/audioplayback_figure3_1.png

3.1 Playback Control

The playback control that the sample code supports include play, pause, stop, skip to next, and skip to previous.

3.2 Trick Play Control

Manipulating "Repeat" alternates between "Repeat mode On" and "Repeat mode Off". The default mode is "Repeat mode On". When the repeat mode is on, the playback of the first song starts after the playback of the last song is finished. When the repeat mode is off, the sample code enters the stopped state after the playback of the last song is finished.

3.3 Acquisition of the Song Information

The information of the song being played is obtained by operating the "Play info" during the playback of the song. Table 3.4 lists the items of information that can be obtained by the "Play info" operation.

/media/uploads/dkato/audioplayback_table3_4.png

3.4 How the Folder Structure is Analyzed

The sample coded analyzes the folder structure in the breadth-first search order. The order in which files are numbered is illustrated in Table 3.5. The sample code does not sort the files by file or folder name.

/media/uploads/dkato/audioplayback_table3_5.png

4.Others

The default setting of serial communication (baud rate etc.) in mbed is shown the following link.
Please refer to the link and change the settings of your PC terminal software.
The default value of baud rate in mbed is 9600, and this application uses baud rate 9600.
https://developer.mbed.org/teams/Renesas/wiki/GR-PEACH-Getting-Started#install-the-usb-serial-communication

decode/decode.cpp

Committer:
Osamu Nakamura
Date:
2017-03-31
Revision:
6:df19c3e787ca
Parent:
5:c140dcdc2d45

File content as of revision 6:df19c3e787ca:

/*******************************************************************************
* DISCLAIMER
* This software is supplied by Renesas Electronics Corporation and is only
* intended for use with Renesas products. No other uses are authorized. This
* software is owned by Renesas Electronics Corporation and is protected under
* all applicable laws, including copyright laws.
* THIS SOFTWARE IS PROVIDED "AS IS" AND RENESAS MAKES NO WARRANTIES REGARDING
* THIS SOFTWARE, WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING BUT NOT
* LIMITED TO WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
* AND NON-INFRINGEMENT. ALL SUCH WARRANTIES ARE EXPRESSLY DISCLAIMED.
* TO THE MAXIMUM EXTENT PERMITTED NOT PROHIBITED BY LAW, NEITHER RENESAS
* ELECTRONICS CORPORATION NOR ANY OF ITS AFFILIATED COMPANIES SHALL BE LIABLE
* FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES FOR
* ANY REASON RELATED TO THIS SOFTWARE, EVEN IF RENESAS OR ITS AFFILIATES HAVE
* BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
* Renesas reserves the right, without notice, to make changes to this software
* and to discontinue the availability of this software. By using this software,
* you agree to the additional terms and conditions found by accessing the
* following link:
* http://www.renesas.com/disclaimer*
* Copyright (C) 2015 Renesas Electronics Corporation. All rights reserved.
*******************************************************************************/

#include "mbed.h"
#include "rtos.h"
#include "misratypes.h"
#include "r_errno.h"
#include "system.h"
#include "decode.h"
#include "audio_out.h"
#include "dec_flac.h"

/*--- Macro definition of mbed-rtos mail ---*/
#define MAIL_QUEUE_SIZE     (12)    /* Queue size */
#define MAIL_PARAM_NUM      (2)     /* Elements number of mail parameter array */

/* dec_mail_t */
#define MAIL_PARAM0         (0)     /* Index number of mail parameter array */
#define MAIL_PARAM1         (1)     /* Index number of mail parameter array */

#define MAIL_PARAM_NON      (0u)    /* Value of unused element of mail parameter array */

/* mail_id = DEC_MAILID_OPEN */
#define MAIL_OPEN_CB        (MAIL_PARAM0)   /* Callback function */
#define MAIL_OPEN_FILE      (MAIL_PARAM1)   /* File handle */

/* mail_id = DEC_MAILID_PLAY : No parameter */

/* mail_id = DEC_MAILID_PAUSE_ON : No parameter */

/* mail_id = DEC_MAILID_PAUSE_OFF : No parameter */

/* mail_id = DEC_MAILID_STOP : No parameter */

/* mail_id = DEC_MAILID_CLOSE */
#define MAIL_CLOSE_CB               (MAIL_PARAM0)   /* Callback function */

/* mail_id = DEC_MAILID_CB_AUD_DATA_OUT */
#define MAIL_DATA_OUT_RESULT        (MAIL_PARAM0)   /* Result of the process */

/* mail_id = DEC_MAILID_SCUX_WRITE_FIN */
#define MAIL_SCUX_WRITE_RESULT      (MAIL_PARAM0)   /* Result of the process */
#define MAIL_SCUX_WRITE_BUF_INDEX   (MAIL_PARAM1)   /* Index number of PCM buffer */

/* mail_id = DEC_MAILID_SCUX_FLUSH_FIN */
#define MAIL_SCUX_FLUSH_RESULT      (MAIL_PARAM0)   /* Result of the process */


/*--- Macro definition of PCM buffer ---*/
#define UNIT_TIME_MS                (50u)   /* Unit time of PCM data processing (ms) */
#define SEC_TO_MSEC                 (1000u)

/* Sample number per uint time (ms) */
#define SAMPLE_NUM_PER_UNIT_MS      (((UNIT_TIME_MS * DEC_INPUT_MAX_SAMPLE_RATE) / SEC_TO_MSEC) * DEC_OUTPUT_CHANNEL_NUM)
/* Max number of samples per 1 block */
#define MAX_SAMPLE_PER_1BLOCK       (DEC_MAX_BLOCK_SIZE * DEC_OUTPUT_CHANNEL_NUM)

#define PCM_BUF_NUM                 (3u)
#define TOTAL_SAMPLE_NUM            (MAX_SAMPLE_PER_1BLOCK + SAMPLE_NUM_PER_UNIT_MS)

#define PCM_BUF_SINGLE              (1)
#define PCM_BUF_TOP_ID              (0)

/*--- Macro definition of R_BSP_Scux ---*/
#define SCUX_INT_LEVEL              (0x80)
#define SCUX_READ_NUM               (DEC_SCUX_READ_NUM)
#define SCUX_WRITE_NUM              (PCM_BUF_NUM)

/* 4 bytes aligned. No cache memory. */
#if defined(__ICCARM__)
#define NC_BSS_SECT                 @ ".mirrorram"
#else
#define NC_BSS_SECT                 __attribute__((section("NC_BSS"),aligned(4)))
#endif

/*--- User defined types of mbed-rtos mail ---*/
typedef enum {
    DEC_MAILID_DUMMY = 0,
    DEC_MAILID_OPEN,            /* Requests the opening of the decoder. */
    DEC_MAILID_PLAY,            /* Requests the starting of the playback. */
    DEC_MAILID_PAUSE_ON,        /* Requests the starting of the pause. */
    DEC_MAILID_PAUSE_OFF,       /* Requests the stopping of the pause. */
    DEC_MAILID_STOP,            /* Requests the stopping of the playback. */
    DEC_MAILID_CLOSE,           /* Requests the closing of the decoder. */
    DEC_MAILID_CB_AUD_DATA_OUT, /* Finished the preparation for the audio output. */
    DEC_MAILID_SCUX_WRITE_FIN,  /* Finished the writing process of SCUX. */
    DEC_MAILID_SCUX_FLUSH_FIN,  /* Finished the flush process of SCUX. */
    DEC_MAILID_NUM
} DEC_MAIL_ID;

typedef struct {
    DEC_MAIL_ID     mail_id;
    uint32_t        param[MAIL_PARAM_NUM];
} dec_mail_t;

/*--- User defined types of decode thread ---*/
/* The playback information of the playback file */
typedef struct {
    SYS_PlayStat    play_stat;  /* Playback status */
    uint32_t        play_time;  /* Playback start time */
    uint32_t        total_time; /* Total playback time */
} play_info_t;

/* Control data of Decode thread */
typedef struct {
    play_info_t     play_info;
    flac_ctrl_t     flac_ctrl;
} dec_ctrl_t;

/* Status of Decode thread */
typedef enum {
    DEC_ST_IDLE = 0,            /* Idle */
    DEC_ST_META_FIN,            /* Finished the decoding until a metadata */
    DEC_ST_PLAY,                /* Decoder start */
    DEC_ST_PAUSE,               /* Decoder pause */
    DEC_ST_STOP_PREPARE,        /* Preparing of decoder stop */
    DEC_ST_STOP,                /* Decoder stop */
    DEC_ST_NUM
} DEC_STATE;

static Mail<dec_mail_t, MAIL_QUEUE_SIZE> mail_box;
static R_BSP_Scux scux(SCUX_CH_0, SCUX_INT_LEVEL, SCUX_WRITE_NUM, SCUX_READ_NUM);

static bool open_proc(flac_ctrl_t * const p_ctrl, 
        FILE * const p_handle, const DEC_CbOpen p_cb);
static void close_proc(flac_ctrl_t * const p_ctrl, const DEC_CbClose p_cb);
static bool play_proc(flac_ctrl_t * const p_ctrl, const uint32_t buf_id,
        int32_t (* const p_buf)[TOTAL_SAMPLE_NUM], const uint32_t element_num);
static bool pause_proc(const uint32_t buf_id,
        int32_t (* const p_buf)[TOTAL_SAMPLE_NUM], const uint32_t element_num);
static uint32_t get_audio_data(flac_ctrl_t * const p_ctrl, 
                                int32_t * const p_buf, const uint32_t buf_num);
static void data_out_callback(const bool result);
static void write_callback(void * p_data, int32_t result, void * p_app_data);
static void flush_callback(int32_t result);
static bool send_mail(const DEC_MAIL_ID mail_id, 
                            const uint32_t param0, const uint32_t param1);
static bool recv_mail(DEC_MAIL_ID * const p_mail_id, 
                        uint32_t * const p_param0, uint32_t * const p_param1);
static void update_decode_stat(const SYS_PlayStat stat, play_info_t * const p_play_info);
static void update_decode_playtime(const uint32_t play_time, play_info_t * const p_play_info);
static void init_decode_playinfo(const uint32_t total_time, play_info_t * const p_play_info);
static void notify_decode_stat(const play_info_t * const p_play_info);

void dec_thread(void const *argument)
{
    dec_ctrl_t                  dec_ctrl;   /* Control data of Decode thread */
    DEC_STATE                   dec_stat;   /* Status of Decode thread */
    DEC_MAIL_ID                 mail_type;
    uint32_t                    mail_param[MAIL_PARAM_NUM];
    uint32_t                    buf_id;
    uint32_t                    buf_num;
    uint32_t                    time_code;
    bool                        result;
#if defined(__ICCARM__)
    static int32_t pcm_buf[PCM_BUF_NUM][TOTAL_SAMPLE_NUM] NC_BSS_SECT;
#else
    static int32_t NC_BSS_SECT  pcm_buf[PCM_BUF_NUM][TOTAL_SAMPLE_NUM];
#endif

    UNUSED_ARG(argument);
    dec_stat = DEC_ST_IDLE;
    while (1) {
        result = recv_mail(&mail_type, &mail_param[MAIL_PARAM0], &mail_param[MAIL_PARAM1]);
        if (result == true) {
            /* State transition processing */
            switch (dec_stat) {
                case DEC_ST_META_FIN:       /* Finished the decoding until a metadata */
                    if (mail_type == DEC_MAILID_PLAY) {
                        time_code = flac_get_total_time(&dec_ctrl.flac_ctrl);
                        init_decode_playinfo(time_code, &dec_ctrl.play_info);
                        update_decode_stat(SYS_PLAYSTAT_PLAY, &dec_ctrl.play_info);
                        (void) aud_req_data_out(&data_out_callback);
                        dec_stat = DEC_ST_PLAY;
                    } else if (mail_type == DEC_MAILID_CLOSE) {
                        scux.ClearStop();
                        close_proc(&dec_ctrl.flac_ctrl, (DEC_CbClose)mail_param[MAIL_CLOSE_CB]);
                        dec_stat = DEC_ST_IDLE;
                    } else {
                        /* DO NOTHING */
                    }
                    break;
                case DEC_ST_PLAY:           /* Decoder start */
                    if (mail_type == DEC_MAILID_PAUSE_ON) {
                        update_decode_stat(SYS_PLAYSTAT_PAUSE, &dec_ctrl.play_info);
                        dec_stat = DEC_ST_PAUSE;
                    } else if (mail_type == DEC_MAILID_STOP) {
                        scux.ClearStop();
                        (void) aud_req_zero_out();
                        update_decode_stat(SYS_PLAYSTAT_STOP, &dec_ctrl.play_info);
                        dec_stat = DEC_ST_STOP;
                    } else if ((mail_type == DEC_MAILID_CB_AUD_DATA_OUT) || 
                               (mail_type == DEC_MAILID_SCUX_WRITE_FIN)) {
                        if (mail_type == DEC_MAILID_SCUX_WRITE_FIN) {
                            buf_id = mail_param[MAIL_SCUX_WRITE_BUF_INDEX];
                            buf_num = PCM_BUF_SINGLE;
                        } else {
                            buf_id = PCM_BUF_TOP_ID;
                            buf_num = PCM_BUF_NUM;
                        }
                        result = play_proc(&dec_ctrl.flac_ctrl, buf_id, &pcm_buf[buf_id], buf_num);
                        if (result == true) {
                            time_code = flac_get_play_time(&dec_ctrl.flac_ctrl);
                            update_decode_playtime(time_code, &dec_ctrl.play_info);
                            /* "dec_stat" variable does not change. */
                        } else {
                            result = scux.FlushStop(&flush_callback);
                            if (result == true) {
                                dec_stat = DEC_ST_STOP_PREPARE;
                            } else {
                                /* Error occurred by SCUX driver. */
                                (void) aud_req_zero_out();
                                update_decode_stat(SYS_PLAYSTAT_STOP, &dec_ctrl.play_info);
                                dec_stat = DEC_ST_STOP;
                            }
                        }
                    } else {
                        /* DO NOTHING */
                    }
                    break;
                case DEC_ST_PAUSE:          /* Decoder pause */
                    if (mail_type == DEC_MAILID_PAUSE_OFF) {
                        update_decode_stat(SYS_PLAYSTAT_PLAY, &dec_ctrl.play_info);
                        dec_stat = DEC_ST_PLAY;
                    } else if (mail_type == DEC_MAILID_STOP) {
                        scux.ClearStop();
                        (void) aud_req_zero_out();
                        update_decode_stat(SYS_PLAYSTAT_STOP, &dec_ctrl.play_info);
                        dec_stat = DEC_ST_STOP;
                    } else if ((mail_type == DEC_MAILID_CB_AUD_DATA_OUT) || 
                               (mail_type == DEC_MAILID_SCUX_WRITE_FIN)) {
                        if (mail_type == DEC_MAILID_SCUX_WRITE_FIN) {
                            buf_id = mail_param[MAIL_SCUX_WRITE_BUF_INDEX];
                            buf_num = PCM_BUF_SINGLE;
                        } else {
                            buf_id = PCM_BUF_TOP_ID;
                            buf_num = PCM_BUF_NUM;
                        }
                        result = pause_proc(buf_id, &pcm_buf[buf_id], buf_num);
                        if (result == true) {
                            /* "dec_stat" variable does not change. */
                        } else {
                            result = scux.FlushStop(&flush_callback);
                            if (result == true) {
                                dec_stat = DEC_ST_STOP_PREPARE;
                            } else {
                                /* Error occurred by SCUX driver. */
                                (void) aud_req_zero_out();
                                update_decode_stat(SYS_PLAYSTAT_STOP, &dec_ctrl.play_info);
                                dec_stat = DEC_ST_STOP;
                            }
                        }
                    } else {
                        /* DO NOTHING */
                    }
                    break;
                case DEC_ST_STOP_PREPARE:   /* Preparing of decoder stop */
                    if (mail_type == DEC_MAILID_SCUX_FLUSH_FIN) {
                        (void) aud_req_zero_out();
                        update_decode_stat(SYS_PLAYSTAT_STOP, &dec_ctrl.play_info);
                        dec_stat = DEC_ST_STOP;
                    } else {
                        /* DO NOTHING */
                    }
                    break;
                case DEC_ST_STOP:           /* Decoder stop */
                    if (mail_type == DEC_MAILID_CLOSE) {
                        close_proc(&dec_ctrl.flac_ctrl, (DEC_CbClose)mail_param[MAIL_CLOSE_CB]);
                        dec_stat = DEC_ST_IDLE;
                    } else {
                        /* DO NOTHING */
                    }
                    break;
                case DEC_ST_IDLE:           /* Idle */
                default:
                    if (mail_type == DEC_MAILID_OPEN) {
                        result = open_proc(&dec_ctrl.flac_ctrl, 
                                           (FILE*)mail_param[MAIL_OPEN_FILE], 
                                           (DEC_CbOpen)mail_param[MAIL_OPEN_CB]);
                        if (result == true) {
                            dec_stat = DEC_ST_META_FIN;
                        } else {
                            /* "dec_stat" variable does not change. */
                        }
                    } else {
                        dec_stat = DEC_ST_IDLE; /* This is fail-safe processing. */
                    }
                    break;
            }
        }
    }
}

bool dec_open(FILE * const p_handle, const DEC_CbOpen p_cb)
{
    bool    ret = false;

    if ((p_handle != NULL) && (p_cb != NULL)) {
        ret = send_mail(DEC_MAILID_OPEN, (uint32_t)p_cb, (uint32_t)p_handle);
    }
    return ret;
}

bool dec_play(void)
{
    bool    ret = false;

    ret = send_mail(DEC_MAILID_PLAY, MAIL_PARAM_NON, MAIL_PARAM_NON);

    return ret;
}

bool dec_pause_on(void)
{
    bool    ret = false;

    ret = send_mail(DEC_MAILID_PAUSE_ON, MAIL_PARAM_NON, MAIL_PARAM_NON);

    return ret;
}

bool dec_pause_off(void)
{
    bool    ret = false;

    ret = send_mail(DEC_MAILID_PAUSE_OFF, MAIL_PARAM_NON, MAIL_PARAM_NON);

    return ret;
}

bool dec_stop(void)
{
    bool    ret;

    ret = send_mail(DEC_MAILID_STOP, MAIL_PARAM_NON, MAIL_PARAM_NON);

    return ret;
}

bool dec_close(const DEC_CbClose p_cb)
{
    bool    ret = false;

    if (p_cb != NULL) {
        ret = send_mail(DEC_MAILID_CLOSE, (uint32_t)p_cb, MAIL_PARAM_NON);
    }
    return ret;
}

bool dec_scux_read(void * const p_data, const uint32_t data_size, 
                            const rbsp_data_conf_t * const p_data_conf)
{
    bool            ret = false;
    int32_t         result;

    result = scux.read(p_data, data_size, p_data_conf);
    if (result == ESUCCESS) {
        ret = true;
    }
    return ret;
}

/** Executes the opening process of the decoder
 *
 *  @param p_ctrl Pointer to the control data of FLAC module.
 *  @param p_handle Pointer to the handle of FLAC file.
 *  @param p_cb Pointer to the callback for notification of the process result.
 *
 *  @returns 
 *    Results of process. true is success. false is failure.
 */
static bool open_proc(flac_ctrl_t * const p_ctrl, FILE * const p_handle, const DEC_CbOpen p_cb)
{
    bool                ret = false;
    bool                result;
    scux_src_usr_cfg_t  conf;

    if ((p_ctrl != NULL) && (p_handle != NULL) && (p_cb != NULL)) {
        result = flac_open(p_handle, p_ctrl);
        if (result == true) {
            /* Sets SCUX config */
            conf.src_enable           = true;
            conf.word_len             = SCUX_DATA_LEN_24;
            conf.mode_sync            = true;
            conf.input_rate           = p_ctrl->sample_rate;
            conf.output_rate          = DEC_OUTPUT_SAMPLE_RATE;
            conf.select_in_data_ch[0] = SELECT_IN_DATA_CH_0;
            conf.select_in_data_ch[1] = SELECT_IN_DATA_CH_1;
            result = scux.SetSrcCfg(&conf);
            if (result == true) {
                ret = scux.TransStart();
            }
        }
        p_cb(ret, p_ctrl->sample_rate, p_ctrl->channel_num);
    }
    return ret;
}

/** Executes the closing process of the decoder
 *
 *  @param p_ctrl Pointer to the control data of FLAC module.
 *  @param p_cb Pointer to the callback for notification of the process result.
 *
 *  @returns 
 *    Results of process. true is success. false is failure.
 */
static void close_proc(flac_ctrl_t * const p_ctrl, const DEC_CbClose p_cb)
{
    if ((p_ctrl != NULL) && (p_cb != NULL)) {
        flac_close(p_ctrl);
        p_cb();
    }
}

/** Executes the starting process of the pause
 *
 *  @param p_ctrl Pointer to the control data of FLAC module.
 *  @param buf_id Index of PCM buffer array.
 *  @param p_buf Pointer to PCM buffer array to use in this process.
 *  @param element_num Elements number of PCM buffer array.
 *
 *  @returns 
 *    Results of process. true is success. false is failure.
 */
static bool pause_proc(const uint32_t buf_id,
        int32_t (* const p_buf)[TOTAL_SAMPLE_NUM], const uint32_t element_num)
{
    bool                ret = false;
    uint32_t            i;
    int32_t             result;
    const uint32_t      pause_data_size = SAMPLE_NUM_PER_UNIT_MS * sizeof(*p_buf[0]);
    rbsp_data_conf_t    cb_conf = {
        &write_callback,
        NULL
    };

    if ((p_buf != NULL) && (element_num > 0u) && 
        (element_num <= PCM_BUF_NUM) && ((buf_id + element_num) <= PCM_BUF_NUM)) {
        /* Audio output process */
        result = ESUCCESS;
        for (i = 0; (i < element_num) && (result == ESUCCESS); i++) {
            (void) memset(&p_buf[i], 0, pause_data_size);
            cb_conf.p_app_data = (void *)(buf_id + i);
            result = scux.write(&p_buf[i], pause_data_size, &cb_conf);
        }
        if (result == ESUCCESS) {
            ret = true;
        }
    }
    return ret;
}

/** Executes the starting process of the playback
 *
 *  @param p_ctrl Pointer to the control data of FLAC module.
 *  @param buf_id Index of PCM buffer array.
 *  @param p_buf Pointer to PCM buffer array to use in this process.
 *  @param element_num Elements number of PCM buffer array.
 *
 *  @returns 
 *    Results of process. true is success. false is failure.
 */
static bool play_proc(flac_ctrl_t * const p_ctrl, const uint32_t buf_id,
        int32_t (* const p_buf)[TOTAL_SAMPLE_NUM], const uint32_t element_num)
{
    bool                ret = false;
    int32_t             result;
    uint32_t            i;
    uint32_t            decoded_cnt;
    uint32_t            num;
    uint32_t            read_byte[PCM_BUF_NUM];
    rbsp_data_conf_t    cb_conf = {
        &write_callback,
        NULL
    };

    if ((p_ctrl != NULL) && (p_buf != NULL) && (element_num > 0u) && 
        (element_num <= PCM_BUF_NUM) && ((buf_id + element_num) <= PCM_BUF_NUM)) {
        /* FLAC decoder process */
        decoded_cnt = 0u;
        do {
            num = get_audio_data(p_ctrl, p_buf[decoded_cnt], sizeof(p_buf[0])/sizeof(*p_buf[0]));
            read_byte[decoded_cnt] = num * sizeof(num);
            if (num > 0u) {
                decoded_cnt++;
            }
        } while ((decoded_cnt < element_num) &&  (num > 0u));
        /* Audio output process */
        if (decoded_cnt > 0u) {
            result = ESUCCESS;
            for (i = 0; (i < decoded_cnt) && (result == ESUCCESS); i++) {
                cb_conf.p_app_data = (void *)(buf_id + i);
                result = scux.write(&p_buf[i], read_byte[i], &cb_conf);
            }
            if (result == ESUCCESS) {
                ret = true;
            }
        }
    }
    return ret;
}

/** Gets the decoded data from FLAC decoder library
 *
 *  @param p_ctrl Pointer to the control data of FLAC module.
 *  @param p_buf Pointer to PCM buffer array to store the decoded data.
 *  @param buf_num Elements number of PCM buffer array.
 *
 *  @returns 
 *    Elements number of decoded data.
 */
static uint32_t get_audio_data(flac_ctrl_t * const p_ctrl, 
                            int32_t * const p_buf, const uint32_t buf_num)
{
    uint32_t    read_cnt = 0u;
    bool        result;

    if ((p_ctrl != NULL) && (p_buf != NULL) && (buf_num > 0u)) {
        result = flac_set_pcm_buf(p_ctrl, p_buf, buf_num);
        while ((result == true) && ((read_cnt + MAX_SAMPLE_PER_1BLOCK) <= buf_num)) {
            result = flac_decode(p_ctrl);
            read_cnt = flac_get_pcm_cnt(p_ctrl);
        }
    }
    return read_cnt;
}

/** Callback function of Audio Out Thread
 *
 *  @param result Result of the process of Audio Out Thread
 */
static void data_out_callback(const bool result)
{
    (void) send_mail(DEC_MAILID_CB_AUD_DATA_OUT, (uint32_t)result, MAIL_PARAM_NON);
}

/** Callback function of SCUX driver
 *
 *  @param p_data Pointer to PCM byffer array.
 *  @param result Result of the process.
 *  @param p_app_data The control ID of PCM buffer.
 */
static void write_callback(void * p_data, int32_t result, void * p_app_data)
{
    const uint32_t  buf_id = (uint32_t)p_app_data;
    bool            flag_result;

    UNUSED_ARG(p_data);
    if (result > 0) {
        flag_result = true;
    } else {
        flag_result = false;
    }
    (void) send_mail(DEC_MAILID_SCUX_WRITE_FIN, (uint32_t)flag_result, buf_id);
}

/** Callback function of SCUX driver
 *
 *  @param result Result of the process.
 */
static void flush_callback(int32_t result)
{
    bool        flag_result;

    if (result > 0) {
        flag_result = true;
    } else {
        flag_result = false;
    }
    (void) send_mail(DEC_MAILID_SCUX_FLUSH_FIN, (uint32_t)flag_result, MAIL_PARAM_NON);
}

/** Sends the mail to Decode thread
 *
 *  @param mail_id Mail ID
 *  @param param0 Parameter 0 of this mail
 *  @param param1 Parameter 1 of this mail
 *
 *  @returns 
 *    Results of process. true is success. false is failure.
 */
static bool send_mail(const DEC_MAIL_ID mail_id, 
                            const uint32_t param0, const uint32_t param1)
{
    bool            ret = false;
    osStatus        stat;
    dec_mail_t      * const p_mail = mail_box.alloc();

    if (p_mail != NULL) {
        p_mail->mail_id = mail_id;
        p_mail->param[MAIL_PARAM0] = param0;
        p_mail->param[MAIL_PARAM1] = param1;
        stat = mail_box.put(p_mail);
        if (stat == osOK) {
            ret = true;
        } else {
            (void) mail_box.free(p_mail);
        }
    }
    return ret;
}

/** Receives the mail to Decode thread
 *
 *  @param p_mail_id Pointer to the variable to store the mail ID
 *  @param p_param0 Pointer to the variable to store the parameter 0 of this mail
 *  @param p_param1 Pointer to the variable to store the parameter 1 of this mail
 *
 *  @returns 
 *    Results of process. true is success. false is failure.
 */
static bool recv_mail(DEC_MAIL_ID * const p_mail_id, 
                        uint32_t * const p_param0, uint32_t * const p_param1)
{
    bool            ret = false;
    osEvent         evt;
    dec_mail_t      *p_mail;
    
    if ((p_mail_id != NULL) && (p_param0 != NULL) && (p_param1 != NULL)) {
        evt = mail_box.get();
        if (evt.status == osEventMail) {
            p_mail = (dec_mail_t *)evt.value.p;
            if (p_mail != NULL) {
                *p_mail_id = p_mail->mail_id;
                *p_param0 = p_mail->param[MAIL_PARAM0];
                *p_param1 = p_mail->param[MAIL_PARAM1];
                ret = true;
            }
            (void) mail_box.free(p_mail);
        }
    }
    return ret;
}

/** Updates the status of Decode thread
 *
 *  @param stat New status of Decode thread
 *  @param p_play_info Pointer to the playback information of the playback file
 */
static void update_decode_stat(const SYS_PlayStat stat, play_info_t * const p_play_info)
{
    if (p_play_info != NULL) {
        if (p_play_info->play_stat != stat) {
            p_play_info->play_stat = stat;
            notify_decode_stat(p_play_info);
        }
    }
}

/** Updates the playback time
 *
 *  @param play_time Current playback time
 *  @param p_play_info Pointer to the playback information of the playback file
 */
static void update_decode_playtime(const uint32_t play_time, play_info_t * const p_play_info)
{
    if (p_play_info != NULL) {
        if (p_play_info->play_time != play_time) {
            p_play_info->play_time = play_time;
            notify_decode_stat(p_play_info);
        }
    }
}

/** Initialises the playback information
 *
 *  @param total_time Total playback time
 *  @param p_play_info Pointer to the playback information of the playback file
 */
static void init_decode_playinfo(const uint32_t total_time, play_info_t * const p_play_info)
{
    if (p_play_info != NULL) {
        p_play_info->play_stat  = SYS_PLAYSTAT_STOP;
        p_play_info->play_time  = 0u;
        p_play_info->total_time = total_time;
    }
}

/** Notifies Main thread of the status of Decode thread
 *
 *  @param p_play_info Pointer to the playback information of the playback file
 */
static void notify_decode_stat(const play_info_t * const p_play_info)
{
    if (p_play_info != NULL) {
        (void) sys_notify_play_time(p_play_info->play_stat, 
                    p_play_info->play_time, p_play_info->total_time);
    }
}