Audio Element¶

The basic building block for the application programmer developing with ADF is the audio_element object. Every decoder, encoder, filter, input stream, or output stream is in fact an Audio Element.

This API has been designed and then used to implement Audio Elements provided by ADF.

The general functionality of an Element is to take some data on input, processes it, and output to the next. Each Element is run as a separate task. To enable control on particular stages of the data lifecycle from the input, during processing and up to the output, the audio_element object provides possibility to trigger callbacks per stage. There are seven types of available callback functions: open, seek, process, close, destroy, read and write, and they are defined in audio_element_cfg_t. Particular Elements typically use a subset of all available callbacks. For instance the MP3 Decoder is using open, process, close and destroy callback functions.

The available Audio Element types intended for development with this API are listed in description of audio_common.h header file under audio_element_type_t enumerator.

API Reference¶

Header File¶

audio_pipeline/include/audio_element.h

Functions¶

audio_element_handle_t audio_element_init(audio_element_cfg_t *config)¶

Initialize audio element with config.

Return

audio_elemenent handle object
NULL

Parameters

config: The configuration

esp_err_t audio_element_deinit(audio_element_handle_t el)¶

Destroy audio element handle object, stop, clear, deletel all.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle

esp_err_t audio_element_setdata(audio_element_handle_t el, void *data)¶

Set context data to element handle object. It can be retrieved by calling audio_element_getdata.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
data: The data pointer

void *audio_element_getdata(audio_element_handle_t el)¶

Get context data from element handle object.

Return

data pointer

Parameters

[in] el: The audio element handle

esp_err_t audio_element_set_tag(audio_element_handle_t el, const char *tag)¶

Set elemenet tag name, or clear if tag = NULL.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] tag: The tag name pointer

char *audio_element_get_tag(audio_element_handle_t el)¶

Get element tag name.

Return

Element tag name pointer

Parameters

[in] el: The audio element handle

esp_err_t audio_element_setinfo(audio_element_handle_t el, audio_element_info_t *info)¶

Set audio element infomation.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
info: The information pointer

esp_err_t audio_element_getinfo(audio_element_handle_t el, audio_element_info_t *info)¶

Get audio element infomation.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
info: The information pointer

esp_err_t audio_element_set_uri(audio_element_handle_t el, const char *uri)¶

Set audio element URI.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] uri: The uri pointer

char *audio_element_get_uri(audio_element_handle_t el)¶

Get audio element URI.

Return

URI pointer

Parameters

[in] el: The audio element handle

esp_err_t audio_element_run(audio_element_handle_t el)¶

Start Audio Element. With this function, audio_element will start as freeRTOS task, and put the task into ‘PAUSED’ state. Note: Element does not actually start when this function returns.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle

esp_err_t audio_element_terminate(audio_element_handle_t el)¶

Terminate Audio Element. With this function, audio_element will exit the task function. Note: this API only sends request. It does not actually terminate immediately when this function returns.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle

esp_err_t audio_element_terminate_with_ticks(audio_element_handle_t el, TickType_t ticks_to_wait)¶

Terminate Audio Element with specific ticks for timeout. With this function, audio_element will exit the task function. Note: this API only sends request. It does not actually terminate immediately when this function returns.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] ticks_to_wait: The maximum amount of time to blocking

esp_err_t audio_element_stop(audio_element_handle_t el)¶

Request stop of the Audio Element. After receiving the stop request, the element will ignore the actions being performed (read/write, wait for the ringbuffer …) and close the task, reset the state variables. Note: this API only sends requests, Element does not actually stop when this function returns.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle

esp_err_t audio_element_wait_for_stop(audio_element_handle_t el)¶

After the audio_element_stop function is called, the Element task will perform some abort procedures. This function will be blocked (Time is DEFAULT_MAX_WAIT_TIME) until Element Task has done and exit.

Return

ESP_OK, Success
ESP_FAIL, The state is not AEL_STATE_RUNNING
ESP_ERR_TIMEOUT, Timeout

Parameters

[in] el: The audio element handle

esp_err_t audio_element_wait_for_stop_ms(audio_element_handle_t el, TickType_t ticks_to_wait)¶

After the audio_element_stop function is called, the Element task will perform some abort procedures. The maximum amount of time should block waiting for Element task has stopped.

Return

ESP_OK, Success
ESP_FAIL, The state is not AEL_STATE_RUNNING
ESP_ERR_TIMEOUT, Timeout

Parameters

[in] el: The audio element handle
[in] ticks_to_wait: The maximum amount of time to wait for stop

esp_err_t audio_element_pause(audio_element_handle_t el)¶

Request audio Element enter ‘PAUSE’ state. In this state, the task will wait for any event.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle

esp_err_t audio_element_resume(audio_element_handle_t el, float wait_for_rb_threshold, TickType_t timeout)¶

Request audio Element enter ‘RUNNING’ state. In this state, the task listens to events and invokes the callback functions. At the same time it will wait until the size/total_size of the output ringbuffer is greater than or equal to wait_for_rb_threshold. If the timeout period has been exceeded and ringbuffer output has not yet reached wait_for_rb_threshold then the function will return.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] wait_for_rb_threshold: The wait for rb threshold (0 .. 1)
[in] timeout: The timeout

esp_err_t audio_element_msg_set_listener(audio_element_handle_t el, audio_event_iface_handle_t listener)¶

This function will add a listener to listen to all events from audio element el. Any event from el->external_event will be send to the listener.

Return

ESP_OK
ESP_FAIL

Parameters

el: The audio element handle
listener: The event will be listen to

esp_err_t audio_element_set_event_callback(audio_element_handle_t el, event_cb_func cb_func, void *ctx)¶

This function will add a callback to be called from audio element el. Any event to caller will cause to call callback function.

Return

ESP_OK
ESP_FAIL

Parameters

el: The audio element handle
cb_func: The callback function
ctx: Caller context

esp_err_t audio_element_msg_remove_listener(audio_element_handle_t el, audio_event_iface_handle_t listener)¶

Remove listener out of el. No new events will be sent to the listener.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
listener: The listener

esp_err_t audio_element_set_input_ringbuf(audio_element_handle_t el, ringbuf_handle_t rb)¶

Set Element input ringbuffer.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] rb: The ringbuffer handle

ringbuf_handle_t audio_element_get_input_ringbuf(audio_element_handle_t el)¶

Get Element input ringbuffer.

Return

ringbuf_handle_t

Parameters

[in] el: The audio element handle

esp_err_t audio_element_set_output_ringbuf(audio_element_handle_t el, ringbuf_handle_t rb)¶

Set Element output ringbuffer.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] rb: The ringbuffer handle

ringbuf_handle_t audio_element_get_output_ringbuf(audio_element_handle_t el)¶

Get Element output ringbuffer.

Return

ringbuf_handle_t

Parameters

[in] el: The audio element handle

audio_element_state_t audio_element_get_state(audio_element_handle_t el)¶

Get current Element state.

Return

audio_element_state_t

Parameters

[in] el: The audio element handle

esp_err_t audio_element_abort_input_ringbuf(audio_element_handle_t el)¶

If the element is requesting data from the input ringbuffer, this function forces it to abort.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle

esp_err_t audio_element_abort_output_ringbuf(audio_element_handle_t el)¶

If the element is waiting to write data to the ringbuffer output, this function forces it to abort.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle

esp_err_t audio_element_wait_for_buffer(audio_element_handle_t el, int size_expect, TickType_t timeout)¶

This function will wait until the sizeof the output ringbuffer is greater than or equal to size_expect. If the timeout period has been exceeded and ringbuffer output has not yet reached size_expect then the function will return ESP_FAIL

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] size_expect: The size expect
[in] timeout: The timeout

esp_err_t audio_element_report_status(audio_element_handle_t el, audio_element_status_t status)¶

Element will sendout event (status) to event by this function.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] status: The status

esp_err_t audio_element_report_info(audio_element_handle_t el)¶

Element will sendout event (information) to event by this function.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle

esp_err_t audio_element_report_codec_fmt(audio_element_handle_t el)¶

Element will sendout event (codec format) to event by this function.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle

esp_err_t audio_element_report_pos(audio_element_handle_t el)¶

Element will sendout event with a duplicate information by this function.

Return

ESP_OK
ESP_FAIL
ESP_ERR_NO_MEM

Parameters

[in] el: The audio element handle

esp_err_t audio_element_set_input_timeout(audio_element_handle_t el, TickType_t timeout)¶

Set input read timeout (default is portMAX_DELAY).

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] timeout: The timeout

esp_err_t audio_element_set_output_timeout(audio_element_handle_t el, TickType_t timeout)¶

Set output read timeout (default is portMAX_DELAY).

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] timeout: The timeout

esp_err_t audio_element_reset_input_ringbuf(audio_element_handle_t el)¶

Reset inputbuffer.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle

esp_err_t audio_element_finish_state(audio_element_handle_t el)¶

Set element finish state.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle

esp_err_t audio_element_change_cmd(audio_element_handle_t el, audio_element_msg_cmd_t cmd)¶

Change element running state with specific command.

Return

ESP_OK
ESP_FAIL
ESP_ERR_INVALID_ARG Element handle is null

Parameters

[in] el: The audio element handle
[in] cmd: Specific command from audio_element_msg_cmd_t

esp_err_t audio_element_reset_output_ringbuf(audio_element_handle_t el)¶

Reset outputbuffer.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle

audio_element_err_t audio_element_input(audio_element_handle_t el, char *buffer, int wanted_size)¶

Call this function to provide Element input data. Depending on setup using ringbuffer or function callback, Element invokes read ringbuffer, or calls read callback funtion.

Return

> 0 number of bytes produced
<=0 audio_element_err_t

Parameters

[in] el: The audio element handle
buffer: The buffer pointer
[in] wanted_size: The wanted size

audio_element_err_t audio_element_output(audio_element_handle_t el, char *buffer, int write_size)¶

Call this function to sendout Element output data. Depending on setup using ringbuffer or function callback, Element will invoke write to ringbuffer, or call write callback funtion.

Return

> 0 number of bytes written
<=0 audio_element_err_t

Parameters

[in] el: The audio element handle
buffer: The buffer pointer
[in] write_size: The write size

esp_err_t audio_element_set_read_cb(audio_element_handle_t el, stream_func fn, void *context)¶

This API allows the application to set a read callback for the first audio_element in the pipeline for allowing the pipeline to interface with other systems. The callback is invoked every time the audio element requires data to be processed.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] fn: Callback read function. The callback function should return number of bytes read or -1 in case of error in reading. Note that the callback function may decide to block and that may block the entire pipeline.
[in] context: An optional context which will be passed to callback function on every invocation

esp_err_t audio_element_set_write_cb(audio_element_handle_t el, stream_func fn, void *context)¶

This API allows the application to set a write callback for the last audio_element in the pipeline for allowing the pipeline to interface with other systems. The callback is invoked every time the audio element has a processed data that needs to be passed forward.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element
[in] fn: Callback write function The callback function should return number of bytes written or -1 in case of error in writing. Note that the callback function may decide to block and that may block the entire pipeline.
[in] context: An optional context which will be passed to callback function on every invocation

stream_func audio_element_get_write_cb(audio_element_handle_t el)¶

Get callback write function that register to the element.

Return

Callback write function pointer
NULL Failed

Parameters

[in] el: The audio element

stream_func audio_element_get_read_cb(audio_element_handle_t el)¶

Get callback read function that register to the element.

Return

Callback read function pointer
NULL Failed

Parameters

[in] el: The audio element

QueueHandle_t audio_element_get_event_queue(audio_element_handle_t el)¶

Get External queue of Emitter. We can read any event that has been send out of Element from this QueueHandle_t.

Return

QueueHandle_t

Parameters

[in] el: The audio element handle

esp_err_t audio_element_set_ringbuf_done(audio_element_handle_t el)¶

Set inputbuffer and outputbuffer have finished.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle

esp_err_t audio_element_reset_state(audio_element_handle_t el)¶

Enforce ‘AEL_STATE_INIT’ state.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle

int audio_element_get_output_ringbuf_size(audio_element_handle_t el)¶

Get Element output ringbuffer size.

Return

=0: Parameter NULL
>0: Size of ringbuffer

Parameters

[in] el: The audio element handle

esp_err_t audio_element_set_output_ringbuf_size(audio_element_handle_t el, int rb_size)¶

Set Element output ringbuffer size.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] rb_size: Size of the ringbuffer

int audio_element_multi_input(audio_element_handle_t el, char *buffer, int wanted_size, int index, TickType_t ticks_to_wait)¶

Call this function to read data from multi input ringbuffer by given index.

Return

ESP_ERR_INVALID_SIZE
Others are same as the rb_read

Parameters

el: The audio element handle
buffer: The buffer pointer
wanted_size: The wanted size
index: The index of multi input ringbuffer, start from 0, should be less than NUMBER_OF_MULTI_RINGBUF
ticks_to_wait: Timeout of ringbuffer

int audio_element_multi_output(audio_element_handle_t el, char *buffer, int wanted_size, TickType_t ticks_to_wait)¶

Call this function write data by multi output ringbuffer.

Return

The return value is same as the rb_write

Parameters

[in] el: The audio element handle
buffer: The buffer pointer
[in] wanted_size: The wanted size
ticks_to_wait: Timeout of ringbuffer

esp_err_t audio_element_set_multi_input_ringbuf(audio_element_handle_t el, ringbuf_handle_t rb, int index)¶

Set multi input ringbuffer Element.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] rb: The ringbuffer handle
[in] index: Index of multi ringbuffer, starts from 0, should be less than NUMBER_OF_MULTI_RINGBUF

esp_err_t audio_element_set_multi_output_ringbuf(audio_element_handle_t el, ringbuf_handle_t rb, int index)¶

Set multi output ringbuffer Element.

Return

ESP_OK
ESP_ERR_INVALID_ARG

Parameters

[in] el: The audio element handle
[in] rb: The ringbuffer handle
[in] index: Index of multi ringbuffer, starts from 0, should be less than NUMBER_OF_MULTI_RINGBUF

ringbuf_handle_t audio_element_get_multi_input_ringbuf(audio_element_handle_t el, int index)¶

Get handle of multi input ringbuffer Element by index.

Return

NULL Error
Others ringbuf_handle_t

Parameters

[in] el: The audio element handle
[in] index: Index of multi ringbuffer, starts from 0, should be less than NUMBER_OF_MULTI_RINGBUF

ringbuf_handle_t audio_element_get_multi_output_ringbuf(audio_element_handle_t el, int index)¶

Get handle of multi output ringbuffer Element by index.

Return

NULL Error
Others ringbuf_handle_t

Parameters

[in] el: The audio element handle
[in] index: Index of multi ringbuffer, starts from 0, should be less than NUMBER_OF_MULTI_RINGBUF

esp_err_t audio_element_process_init(audio_element_handle_t el)¶

Provides a way to call element’s open

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle

esp_err_t audio_element_process_deinit(audio_element_handle_t el)¶

Provides a way to call element’s close

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle

esp_err_t audio_element_seek(audio_element_handle_t el, void *in_data, int in_size, void *out_data, int *out_size)¶

Call element’s seek

Return

ESP_OK
ESP_FAIL
ESP_ERR_NOT_SUPPORTED

Parameters

[in] el: The audio element handle
[in] in_data: A pointer to in data
[in] in_size: The size of the in_data
[out] out_data: A pointer to the out data
[out] out_size: The size of the out_data

bool audio_element_is_stopping(audio_element_handle_t el)¶

Get Element stopping flag.

Return

element’s stopping flag

Parameters

[in] el: The audio element handle

esp_err_t audio_element_update_byte_pos(audio_element_handle_t el, int pos)¶

Update the byte position of element information.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] pos: The byte_pos accumulated by this value

esp_err_t audio_element_set_byte_pos(audio_element_handle_t el, int pos)¶

Set the byte position of element information.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] pos: This value is assigned to byte_pos

esp_err_t audio_element_update_total_bytes(audio_element_handle_t el, int total_bytes)¶

Update the total bytes of element information.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] total_bytes: The total_bytes accumulated by this value

esp_err_t audio_element_set_total_bytes(audio_element_handle_t el, int total_bytes)¶

Set the total bytes of element information.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] total_bytes: This value is assigned to total_bytes

esp_err_t audio_element_set_bps(audio_element_handle_t el, int bit_rate)¶

Set the bps of element information.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] bit_rate: This value is assigned to bps

esp_err_t audio_element_set_codec_fmt(audio_element_handle_t el, int format)¶

Set the codec format of element information.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] format: This value is assigned to codec_fmt

esp_err_t audio_element_set_music_info(audio_element_handle_t el, int sample_rates, int channels, int bits)¶

Set the sample_rate, channels, bits of element information.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] sample_rates: Sample_rates of music information
[in] channels: Channels of music information
[in] bits: Bits of music information

esp_err_t audio_element_set_duration(audio_element_handle_t el, int duration)¶

Set the duration of element information.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] duration: This value is assigned to duration

esp_err_t audio_element_set_reserve_user0(audio_element_handle_t el, int user_data0)¶

Set the user_data_0 of element information.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] user_data0: This value is assigned to user_data_0

esp_err_t audio_element_set_reserve_user1(audio_element_handle_t el, int user_data1)¶

Set the user_data_1 of element information.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] user_data1: This value is assigned to user_data_1

esp_err_t audio_element_set_reserve_user2(audio_element_handle_t el, int user_data2)¶

Set the user_data_2 of element information.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] user_data2: This value is assigned to user_data_2

esp_err_t audio_element_set_reserve_user3(audio_element_handle_t el, int user_data3)¶

Set the user_data_3 of element information.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] user_data3: This value is assigned to user_data_3

esp_err_t audio_element_set_reserve_user4(audio_element_handle_t el, int user_data4)¶

Set the user_data_4 of element information.

Return

ESP_OK
ESP_FAIL

Parameters

[in] el: The audio element handle
[in] user_data4: This value is assigned to user_data_4

Structures¶

struct audio_element_reserve_data_t¶

Audio Element user reserved data.

Public Members

int user_data_0¶: user data 0

int user_data_1¶: user data 1

int user_data_2¶: user data 2

int user_data_3¶: user data 3

int user_data_4¶: user data 4

struct audio_element_info_t¶

Audio Element informations.

Public Members

int sample_rates¶: Sample rates in Hz

int channels¶: Number of audio channel, mono is 1, stereo is 2

int bits¶: Bit wide (8, 16, 24, 32 bits)

int bps¶: Bit per second

int64_t byte_pos¶: The current position (in bytes) being processed for an element

int64_t total_bytes¶: The total bytes for an element

int duration¶: The duration for an element (optional)

char *uri¶: URI (optional)

esp_codec_type_t codec_fmt¶: Music format (optional)

audio_element_reserve_data_t reserve_data¶: This value is reserved for user use (optional)

struct audio_element_cfg_t¶

Audio Element configurations. Each Element at startup will be a self-running task. These tasks will execute the callback open -> [loop: read -> process -> write] -> close. These callback functions are provided by the user corresponding to this configuration.

Public Members

el_io_func open¶: Open callback function

ctrl_func seek¶: Seek callback function

process_func process¶: Process callback function

el_io_func close¶: Close callback function

el_io_func destroy¶: Destroy callback function

stream_func read¶: Read callback function

stream_func write¶: Write callback function

int buffer_len¶: Buffer length use for an Element

int task_stack¶: Element task stack

int task_prio¶: Element task priority (based on freeRTOS priority)

int task_core¶: Element task running in core (0 or 1)

int out_rb_size¶: Output ringbuffer size

void *data¶: User context

const char *tag¶: Element tag

bool stack_in_ext¶: Try to allocate stack in external memory

int multi_in_rb_num¶: The number of multiple input ringbuffer

int multi_out_rb_num¶: The number of multiple output ringbuffer

Macros¶

AUDIO_ELEMENT_INFO_DEFAULT()¶

DEFAULT_ELEMENT_RINGBUF_SIZE¶

DEFAULT_ELEMENT_BUFFER_LENGTH¶

DEFAULT_ELEMENT_STACK_SIZE¶

DEFAULT_ELEMENT_TASK_PRIO¶

DEFAULT_ELEMENT_TASK_CORE¶

DEFAULT_AUDIO_ELEMENT_CONFIG()¶

Type Definitions¶

typedef struct audio_element *audio_element_handle_t¶

typedef esp_err_t (*el_io_func)(audio_element_handle_t self)¶

typedef audio_element_err_t (*process_func)(audio_element_handle_t self, char *el_buffer, int el_buf_len)¶

typedef audio_element_err_t (*stream_func)(audio_element_handle_t self, char *buffer, int len, TickType_t ticks_to_wait, void *context)¶

typedef esp_err_t (*event_cb_func)(audio_element_handle_t el, audio_event_iface_msg_t *event, void *ctx)¶

typedef esp_err_t (*ctrl_func)(audio_element_handle_t self, void *in_data, int in_size, void *out_data, int *out_size)¶

Enumerations¶

enum audio_element_err_t¶

Values:

AEL_IO_OK = ESP_OK¶

AEL_IO_FAIL = ESP_FAIL¶

AEL_IO_DONE = -2¶

AEL_IO_ABORT = -3¶

AEL_IO_TIMEOUT = -4¶

AEL_PROCESS_FAIL = -5¶

enum audio_element_state_t¶

Audio element state.

Values:

AEL_STATE_NONE = 0¶

AEL_STATE_INIT = 1¶

AEL_STATE_INITIALIZING = 2¶

AEL_STATE_RUNNING = 3¶

AEL_STATE_PAUSED = 4¶

AEL_STATE_STOPPED = 5¶

AEL_STATE_FINISHED = 6¶

AEL_STATE_ERROR = 7¶

enum audio_element_msg_cmd_t¶

Audio element action command, process on dispatcher

Values:

AEL_MSG_CMD_NONE = 0¶

AEL_MSG_CMD_FINISH = 2¶

AEL_MSG_CMD_STOP = 3¶

AEL_MSG_CMD_PAUSE = 4¶

AEL_MSG_CMD_RESUME = 5¶

AEL_MSG_CMD_DESTROY = 6¶

AEL_MSG_CMD_REPORT_STATUS = 8¶

AEL_MSG_CMD_REPORT_MUSIC_INFO = 9¶

AEL_MSG_CMD_REPORT_CODEC_FMT = 10¶

AEL_MSG_CMD_REPORT_POSITION = 11¶

enum audio_element_status_t¶

Audio element status report

Values:

AEL_STATUS_NONE = 0¶

AEL_STATUS_ERROR_OPEN = 1¶

AEL_STATUS_ERROR_INPUT = 2¶

AEL_STATUS_ERROR_PROCESS = 3¶

AEL_STATUS_ERROR_OUTPUT = 4¶

AEL_STATUS_ERROR_CLOSE = 5¶

AEL_STATUS_ERROR_TIMEOUT = 6¶

AEL_STATUS_ERROR_UNKNOWN = 7¶

AEL_STATUS_INPUT_DONE = 8¶

AEL_STATUS_INPUT_BUFFERING = 9¶

AEL_STATUS_OUTPUT_DONE = 10¶

AEL_STATUS_OUTPUT_BUFFERING = 11¶

AEL_STATUS_STATE_RUNNING = 12¶

AEL_STATUS_STATE_PAUSED = 13¶

AEL_STATUS_STATE_STOPPED = 14¶

AEL_STATUS_STATE_FINISHED = 15¶

AEL_STATUS_MOUNTED = 16¶

AEL_STATUS_UNMOUNTED = 17¶

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