GstMessage

## GstMessage GstMessage — Lightweight objects to signal the application of pipeline events |

## Synopsis

    #include <gst/gst.h>

                        GstMessage;
    enum                GstMessageType;
    #define             GST_MESSAGE_SRC                     (message)
    #define             GST_MESSAGE_TIMESTAMP               (message)
    #define             GST_MESSAGE_TYPE                    (message)
    #define             GST_MESSAGE_TYPE_NAME               (message)
    #define             GST_MESSAGE_TRACE_NAME
    GQuark              gst_message_type_to_quark           (GstMessageType type);
    const gchar*        gst_message_type_get_name           (GstMessageType type);
    GstMessage*         gst_message_ref                     (GstMessage *msg);
    #define             gst_message_unref                   (msg)
    #define             gst_message_copy                    (msg)
    const GstStructure* gst_message_get_structure           (GstMessage *message);
    #define             gst_message_make_writable           (msg)
    GstMessage*         gst_message_new_eos                 (GstObject *src);
    GstMessage*         gst_message_new_error               (GstObject *src,
                                                             GError *error,
                                                             const gchar *debug);
    void                gst_message_parse_error             (GstMessage *message,
                                                             GError **gerror,
                                                             gchar **debug);
    GstMessage*         gst_message_new_warning             (GstObject *src,
                                                             GError *error,
                                                             const gchar *debug);
    void                gst_message_parse_warning           (GstMessage *message,
                                                             GError **gerror,
                                                             gchar **debug);
    GstMessage*         gst_message_new_info                (GstObject *src,
                                                             GError *error,
                                                             const gchar *debug);
    void                gst_message_parse_info              (GstMessage *message,
                                                             GError **gerror,
                                                             gchar **debug);
    GstMessage*         gst_message_new_tag                 (GstObject *src,
                                                             GstTagList *tag_list);
    void                gst_message_parse_tag               (GstMessage *message,
                                                             GstTagList **tag_list);
    GstMessage*         gst_message_new_buffering           (GstObject *src,
                                                             gint percent);
    void                gst_message_parse_buffering         (GstMessage *message,
                                                             gint *percent);
    void                gst_message_set_buffering_stats     (GstMessage *message,
                                                             GstBufferingMode mode,
                                                             gint avg_in,
                                                             gint avg_out,
                                                             gint64 buffering_left);
    void                gst_message_parse_buffering_stats   (GstMessage *message,
                                                             GstBufferingMode *mode,
                                                             gint *avg_in,
                                                             gint *avg_out,
                                                             gint64 *buffering_left);
    GstMessage*         gst_message_new_state_changed       (GstObject *src,
                                                             GstState oldstate,
                                                             GstState newstate,
                                                             GstState pending);
    void                gst_message_parse_state_changed     (GstMessage *message,
                                                             GstState *oldstate,
                                                             GstState *newstate,
                                                             GstState *pending);
    GstMessage*         gst_message_new_state_dirty         (GstObject *src);
    GstMessage*         gst_message_new_clock_provide       (GstObject *src,
                                                             GstClock *clock,
                                                             gboolean ready);
    void                gst_message_parse_clock_provide     (GstMessage *message,
                                                             GstClock **clock,
                                                             gboolean *ready);
    GstMessage*         gst_message_new_clock_lost          (GstObject *src,
                                                             GstClock *clock);
    void                gst_message_parse_clock_lost        (GstMessage *message,
                                                             GstClock **clock);
    GstMessage*         gst_message_new_new_clock           (GstObject *src,
                                                             GstClock *clock);
    void                gst_message_parse_new_clock         (GstMessage *message,
                                                             GstClock **clock);
    GstMessage*         gst_message_new_application         (GstObject *src,
                                                             GstStructure *structure);
    GstMessage*         gst_message_new_element             (GstObject *src,
                                                             GstStructure *structure);
    GstMessage*         gst_message_new_custom              (GstMessageType type,
                                                             GstObject *src,
                                                             GstStructure *structure);
    GstMessage*         gst_message_new_segment_start       (GstObject *src,
                                                             GstFormat format,
                                                             gint64 position);
    void                gst_message_parse_segment_start     (GstMessage *message,
                                                             GstFormat *format,
                                                             gint64 *position);
    GstMessage*         gst_message_new_segment_done        (GstObject *src,
                                                             GstFormat format,
                                                             gint64 position);
    void                gst_message_parse_segment_done      (GstMessage *message,
                                                             GstFormat *format,
                                                             gint64 *position);
    GstMessage*         gst_message_new_duration            (GstObject *src,
                                                             GstFormat format,
                                                             gint64 duration);
    void                gst_message_parse_duration          (GstMessage *message,
                                                             GstFormat *format,
                                                             gint64 *duration);
    GstMessage*         gst_message_new_latency             (GstObject *src);
    GstMessage*         gst_message_new_async_start         (GstObject *src,
                                                             gboolean new_base_time);
    void                gst_message_parse_async_start       (GstMessage *message,
                                                             gboolean *new_base_time);
    GstMessage*         gst_message_new_async_done          (GstObject *src);

## Description

Messages are implemented as a subclass of GstMiniObject with a generic GstStructure as the content. This allows for writing custom messages without requiring an API change while allowing a wide range of different types of messages.

Messages are posted by objects in the pipeline and are passed to the application using the GstBus.

The basic use pattern of posting a message on a GstBus is as follows:

Example 11. Posting a GstMessage

       gst_bus_post (bus, gst_message_new_eos());

A GstElement usually posts messages on the bus provided by the parent container using `gst_element_post_message()`.

Last reviewed on 2005-11-09 (0.9.4)

## Details

### GstMessage

    typedef struct {
      GstMiniObject mini_object;

      GstMessageType type;
      guint64 timestamp;
      GstObject *src;

      GstStructure *structure;
    } GstMessage;

A GstMessage.

GstMiniObject `mini_object`; | the parent structure
GstMessageType `type`; | the GstMessageType of the message
guint64 `timestamp`; | the timestamp of the message
GstObject *`src`; | the src of the message
GstStructure *`structure`; | the GstStructure containing the message info.

### enum GstMessageType

    typedef enum
    {
      GST_MESSAGE_UNKNOWN           = 0,
      GST_MESSAGE_EOS               = (1 << 0),
      GST_MESSAGE_ERROR             = (1 << 1),
      GST_MESSAGE_WARNING           = (1 << 2),
      GST_MESSAGE_INFO              = (1 << 3),
      GST_MESSAGE_TAG               = (1 << 4),
      GST_MESSAGE_BUFFERING         = (1 << 5),
      GST_MESSAGE_STATE_CHANGED     = (1 << 6),
      GST_MESSAGE_STATE_DIRTY       = (1 << 7),
      GST_MESSAGE_STEP_DONE         = (1 << 8),
      GST_MESSAGE_CLOCK_PROVIDE     = (1 << 9),
      GST_MESSAGE_CLOCK_LOST        = (1 << 10),
      GST_MESSAGE_NEW_CLOCK         = (1 << 11),
      GST_MESSAGE_STRUCTURE_CHANGE  = (1 << 12),
      GST_MESSAGE_STREAM_STATUS     = (1 << 13),
      GST_MESSAGE_APPLICATION       = (1 << 14),
      GST_MESSAGE_ELEMENT           = (1 << 15),
      GST_MESSAGE_SEGMENT_START     = (1 << 16),
      GST_MESSAGE_SEGMENT_DONE      = (1 << 17),
      GST_MESSAGE_DURATION          = (1 << 18),
      GST_MESSAGE_LATENCY           = (1 << 19),
      GST_MESSAGE_ASYNC_START       = (1 << 20),
      GST_MESSAGE_ASYNC_DONE        = (1 << 21),
      GST_MESSAGE_ANY               = ~0
    } GstMessageType;

The different message types that are available.

`GST_MESSAGE_UNKNOWN` | an undefined message
`GST_MESSAGE_EOS` | end-of-stream reached in a pipeline. The application will only receive this message in the PLAYING state and every time it sets a pipeline to PLAYING that is in the EOS state. The application can perform a flushing seek in the pipeline, which will undo the EOS state again.
`GST_MESSAGE_ERROR` | an error occured. Whe the application receives an error message it should stop playback of the pipeline and not assume that more data will be played.
`GST_MESSAGE_WARNING` | a warning occured.
`GST_MESSAGE_INFO` | an info message occured
`GST_MESSAGE_TAG` | a tag was found.
`GST_MESSAGE_BUFFERING` | the pipeline is buffering. When the application receives a buffering message in the PLAYING state for a non-live pipeline it must PAUSE the pipeline until the buffering completes, when the percentage field in the message is 100%. For live pipelines, no action must be performed and the buffering percentage can be used to inform the user about the progress.
`GST_MESSAGE_STATE_CHANGED` | a state change happened
`GST_MESSAGE_STATE_DIRTY` | an element changed state in a streaming thread. This message is deprecated.
`GST_MESSAGE_STEP_DONE` | a framestep finished. This message is not yet implemented.
`GST_MESSAGE_CLOCK_PROVIDE` | an element notifies its capability of providing a clock. This message is used internally and never forwarded to the application.
`GST_MESSAGE_CLOCK_LOST` | The current clock as selected by the pipeline became unusable. The pipeline will select a new clock on the next PLAYING state change.
`GST_MESSAGE_NEW_CLOCK` | a new clock was selected in the pipeline.
`GST_MESSAGE_STRUCTURE_CHANGE` | the structure of the pipeline changed. Not implemented yet.
`GST_MESSAGE_STREAM_STATUS` | status about a stream, emitted when it starts, stops, errors, etc.. Not implemented yet.
`GST_MESSAGE_APPLICATION` | message posted by the application, possibly via an application-specific element.
`GST_MESSAGE_ELEMENT` | element-specific message, see the specific element's documentation
`GST_MESSAGE_SEGMENT_START` | pipeline started playback of a segment. This message is used internally and never forwarded to the application.
`GST_MESSAGE_SEGMENT_DONE` | pipeline completed playback of a segment. This message is forwarded to the application after all elements that posted `GST_MESSAGE_SEGMENT_START` posted a GST_MESSAGE_SEGMENT_DONE message.
`GST_MESSAGE_DURATION` | The duration of a pipeline changed. The application can get the new duration with a duration query.
`GST_MESSAGE_LATENCY` | Posted by elements when their latency changes. The pipeline will calculate and distribute a new latency. Since: 0.10.12
`GST_MESSAGE_ASYNC_START` | Posted by elements when they start an ASYNC state change. This message is not forwarded to the application but is used internally. Since: 0.10.13.
`GST_MESSAGE_ASYNC_DONE` | Posted by elements when they complete an ASYNC state change. The application will only receive this message from the toplevel pipeline. Since: 0.10.13
`GST_MESSAGE_ANY` | mask for all of the above messages.

### GST_MESSAGE_SRC()

    #define GST_MESSAGE_SRC(message)	(GST_MESSAGE(message)->src)

Get the object that posted `message`.

`message` : | a GstMessage

### GST_MESSAGE_TIMESTAMP()

    #define GST_MESSAGE_TIMESTAMP(message)	(GST_MESSAGE(message)->timestamp)

Get the timestamp of `message`. This is the timestamp when the message was created.

`message` : | a GstMessage

### GST_MESSAGE_TYPE()

    #define GST_MESSAGE_TYPE(message)	(GST_MESSAGE(message)->type)

Get the GstMessageType of `message`.

`message` : | a GstMessage

### GST_MESSAGE_TYPE_NAME()

    #define GST_MESSAGE_TYPE_NAME(message)	gst_message_type_get_name(GST_MESSAGE_TYPE(message))

Get a constant string representation of the GstMessageType of `message`.

`message` : | a GstMessage

Since 0.10.4

### GST_MESSAGE_TRACE_NAME

    #define GST_MESSAGE_TRACE_NAME	"GstMessage"

The name used for memory allocation tracing

### gst_message_type_to_quark ()

    GQuark              gst_message_type_to_quark           (GstMessageType type);

Get the unique quark for the given message type.

`type` : | the message type
Returns : | the quark associated with the message type

### gst_message_type_get_name ()

    const gchar*        gst_message_type_get_name           (GstMessageType type);

Get a printable name for the given message type. Do not modify or free.

`type` : | the message type
Returns : | a reference to the static name of the message.

### gst_message_ref ()

    GstMessage*         gst_message_ref                     (GstMessage *msg);

Convenience macro to increase the reference count of the message.

`msg` : | the message to ref
Returns : | `msg` (for convenience when doing assignments)

### gst_message_unref()

    #define         gst_message_unref(msg)		gst_mini_object_unref (GST_MINI_OBJECT (msg))

Convenience macro to decrease the reference count of the message, possibly freeing it.

`msg` : | the message to unref

### gst_message_copy()

    #define         gst_message_copy(msg)		GST_MESSAGE (gst_mini_object_copy (GST_MINI_OBJECT (msg)))

Creates a copy of the message. Returns a copy of the message.

MT safe

`msg` : | the message to copy

### gst_message_get_structure ()

    const GstStructure* gst_message_get_structure           (GstMessage *message);

Access the structure of the message.

`message` : | The GstMessage.
Returns : | The structure of the message. The structure is still owned by the message, which means that you should not free it and that the pointer becomes invalid when you free the message. MT safe.

### gst_message_make_writable()

    #define         gst_message_make_writable(msg)	GST_MESSAGE (gst_mini_object_make_writable (GST_MINI_OBJECT (msg)))

Checks if a message is writable. If not, a writable copy is made and returned. Returns a message (possibly a duplicate) that is writable.

MT safe

`msg` : | the message to make writable

### gst_message_new_eos ()

    GstMessage*         gst_message_new_eos                 (GstObject *src);

Create a new eos message. This message is generated and posted in the sink elements of a GstBin. The bin will only forward the EOS message to the application if all sinks have posted an EOS message.

`src` : | The object originating the message.
Returns : | The new eos message. MT safe.

### gst_message_new_error ()

    GstMessage*         gst_message_new_error               (GstObject *src,
                                                             GError *error,
                                                             const gchar *debug);

Create a new error message. The message will copy `error` and `debug`. This message is posted by element when a fatal event occured. The pipeline will probably (partially) stop. The application receiving this message should stop the pipeline.

`src` : | The object originating the message.
`error` : | The GError for this message.
`debug` : | A debugging string.
Returns : | The new error message. MT safe.

### gst_message_parse_error ()

    void                gst_message_parse_error             (GstMessage *message,
                                                             GError **gerror,
                                                             gchar **debug);

Extracts the GError and debug string from the GstMessage. The values returned in the output arguments are copies; the caller must free them when done.

MT safe.

`message` : | A valid GstMessage of type GST_MESSAGE_ERROR.
`gerror` : | Location for the GError
`debug` : | Location for the debug message, or NULL

### gst_message_new_warning ()

    GstMessage*         gst_message_new_warning             (GstObject *src,
                                                             GError *error,
                                                             const gchar *debug);

Create a new warning message. The message will make copies of `error` and `debug`.

`src` : | The object originating the message.
`error` : | The GError for this message.
`debug` : | A debugging string.
Returns : | The new warning message. MT safe.

### gst_message_parse_warning ()

    void                gst_message_parse_warning           (GstMessage *message,
                                                             GError **gerror,
                                                             gchar **debug);

Extracts the GError and debug string from the GstMessage. The values returned in the output arguments are copies; the caller must free them when done.

MT safe.

`message` : | A valid GstMessage of type GST_MESSAGE_WARNING.
`gerror` : | Location for the GError
`debug` : | Location for the debug message, or NULL

### gst_message_new_info ()

    GstMessage*         gst_message_new_info                (GstObject *src,
                                                             GError *error,
                                                             const gchar *debug);

Create a new info message. The message will make copies of `error` and `debug`.

`src` : | The object originating the message.
`error` : | The GError for this message.
`debug` : | A debugging string.
Returns : | The new info message.

Since 0.10.12 MT safe.

### gst_message_parse_info ()

    void                gst_message_parse_info              (GstMessage *message,
                                                             GError **gerror,
                                                             gchar **debug);

Extracts the GError and debug string from the GstMessage. The values returned in the output arguments are copies; the caller must free them when done.

MT safe.

`message` : | A valid GstMessage of type GST_MESSAGE_INFO.
`gerror` : | Location for the GError
`debug` : | Location for the debug message, or NULL

Since 0.10.12

### gst_message_new_tag ()

    GstMessage*         gst_message_new_tag                 (GstObject *src,
                                                             GstTagList *tag_list);

Create a new tag message. The message will take ownership of the tag list. The message is posted by elements that discovered a new taglist.

`src` : | The object originating the message.
`tag_list` : | The tag list for the message.
Returns : | The new tag message. MT safe.

### gst_message_parse_tag ()

    void                gst_message_parse_tag               (GstMessage *message,
                                                             GstTagList **tag_list);

Extracts the tag list from the GstMessage. The tag list returned in the output argument is a copy; the caller must free it when done.

MT safe.

`message` : | A valid GstMessage of type GST_MESSAGE_TAG.
`tag_list` : | Return location for the tag-list.

### gst_message_new_buffering ()

    GstMessage*         gst_message_new_buffering           (GstObject *src,
                                                             gint percent);

Create a new buffering message. This message can be posted by an element that needs to buffer data before it can continue processing. `percent` should be a value between 0 and 100. A value of 100 means that the buffering completed.

When `percent` is < 100 the application should PAUSE a PLAYING pipeline. When `percent` is 100, the application can set the pipeline (back) to PLAYING. The application must be prepared to receive BUFFERING messages in the PREROLLING state and may only set the pipeline to PLAYING after receiving a message with `percent` set to 100, which can happen after the pipeline completed prerolling.

`src` : | The object originating the message.
`percent` : | The buffering percent
Returns : | The new buffering message.

Since 0.10.11 MT safe.

### gst_message_parse_buffering ()

    void                gst_message_parse_buffering         (GstMessage *message,
                                                             gint *percent);

Extracts the buffering percent from the GstMessage. see also `gst_message_new_buffering()`.

`message` : | A valid GstMessage of type GST_MESSAGE_BUFFERING.
`percent` : | Return location for the percent.

Since 0.10.11 MT safe.

### gst_message_set_buffering_stats ()

    void                gst_message_set_buffering_stats     (GstMessage *message,
                                                             GstBufferingMode mode,
                                                             gint avg_in,
                                                             gint avg_out,
                                                             gint64 buffering_left);

Configures the buffering stats values in `message`.

`message` : | A valid GstMessage of type GST_MESSAGE_BUFFERING.
`mode` : | a buffering mode
`avg_in` : | the average input rate
`avg_out` : | the average output rate
`buffering_left` : | amount of buffering time left in milliseconds

Since 0.10.20

### gst_message_parse_buffering_stats ()

    void                gst_message_parse_buffering_stats   (GstMessage *message,
                                                             GstBufferingMode *mode,
                                                             gint *avg_in,
                                                             gint *avg_out,
                                                             gint64 *buffering_left);

Extracts the buffering stats values from `message`.

`message` : | A valid GstMessage of type GST_MESSAGE_BUFFERING.
`mode` : | a buffering mode
`avg_in` : | the average input rate
`avg_out` : | the average output rate
`buffering_left` : | amount of buffering time left in milliseconds.

Since 0.10.20

### gst_message_new_state_changed ()

    GstMessage*         gst_message_new_state_changed       (GstObject *src,
                                                             GstState oldstate,
                                                             GstState newstate,
                                                             GstState pending);

Create a state change message. This message is posted whenever an element changed its state.

`src` : | the object originating the message
`oldstate` : | the previous state
`newstate` : | the new (current) state
`pending` : | the pending (target) state
Returns : | The new state change message. MT safe.

### gst_message_parse_state_changed ()

    void                gst_message_parse_state_changed     (GstMessage *message,
                                                             GstState *oldstate,
                                                             GstState *newstate,
                                                             GstState *pending);

Extracts the old and new states from the GstMessage.

MT safe.

`message` : | a valid GstMessage of type GST_MESSAGE_STATE_CHANGED
`oldstate` : | the previous state, or NULL
`newstate` : | the new (current) state, or NULL
`pending` : | the pending (target) state, or NULL

### gst_message_new_state_dirty ()

    GstMessage*         gst_message_new_state_dirty         (GstObject *src);

Create a state dirty message. This message is posted whenever an element changed its state asynchronously and is used internally to update the states of container objects.

`src` : | the object originating the message
Returns : | The new state dirty message. MT safe.

### gst_message_new_clock_provide ()

    GstMessage*         gst_message_new_clock_provide       (GstObject *src,
                                                             GstClock *clock,
                                                             gboolean ready);

Create a clock provide message. This message is posted whenever an element is ready to provide a clock or lost its ability to provide a clock (maybe because it paused or became EOS).

This message is mainly used internally to manage the clock selection.

`src` : | The object originating the message.
`clock` : | The clock it provides
`ready` : | TRUE if the sender can provide a clock
Returns : | The new provide clock message. MT safe.

### gst_message_parse_clock_provide ()

    void                gst_message_parse_clock_provide     (GstMessage *message,
                                                             GstClock **clock,
                                                             gboolean *ready);

Extracts the clock and ready flag from the GstMessage. The clock object returned remains valid until the message is freed.

MT safe.

`message` : | A valid GstMessage of type GST_MESSAGE_CLOCK_PROVIDE.
`clock` : | A pointer to hold a clock object.
`ready` : | A pointer to hold the ready flag.

### gst_message_new_clock_lost ()

    GstMessage*         gst_message_new_clock_lost          (GstObject *src,
                                                             GstClock *clock);

Create a clock lost message. This message is posted whenever the clock is not valid anymore.

If this message is posted by the pipeline, the pipeline will select a new clock again when it goes to PLAYING. It might therefore be needed to set the pipeline to PAUSED and PLAYING again.

`src` : | The object originating the message.
`clock` : | the clock that was lost
Returns : | The new clock lost message. MT safe.

### gst_message_parse_clock_lost ()

    void                gst_message_parse_clock_lost        (GstMessage *message,
                                                             GstClock **clock);

Extracts the lost clock from the GstMessage. The clock object returned remains valid until the message is freed.

MT safe.

`message` : | A valid GstMessage of type GST_MESSAGE_CLOCK_LOST.
`clock` : | A pointer to hold the lost clock

### gst_message_new_new_clock ()

    GstMessage*         gst_message_new_new_clock           (GstObject *src,
                                                             GstClock *clock);

Create a new clock message. This message is posted whenever the pipeline selectes a new clock for the pipeline.

`src` : | The object originating the message.
`clock` : | the new selected clock
Returns : | The new new clock message. MT safe.

### gst_message_parse_new_clock ()

    void                gst_message_parse_new_clock         (GstMessage *message,
                                                             GstClock **clock);

Extracts the new clock from the GstMessage. The clock object returned remains valid until the message is freed.

MT safe.

`message` : | A valid GstMessage of type GST_MESSAGE_NEW_CLOCK.
`clock` : | A pointer to hold the selected new clock

### gst_message_new_application ()

    GstMessage*         gst_message_new_application         (GstObject *src,
                                                             GstStructure *structure);

Create a new application-typed message. GStreamer will never create these messages; they are a gift from us to you. Enjoy.

`src` : | The object originating the message.
`structure` : | The structure for the message. The message will take ownership of the structure.
Returns : | The new application message. MT safe.

### gst_message_new_element ()

    GstMessage*         gst_message_new_element             (GstObject *src,
                                                             GstStructure *structure);

Create a new element-specific message. This is meant as a generic way of allowing one-way communication from an element to an application, for example "the firewire cable was unplugged". The format of the message should be documented in the element's documentation. The structure field can be NULL.

`src` : | The object originating the message.
`structure` : | The structure for the message. The message will take ownership of the structure.
Returns : | The new element message. MT safe.

### gst_message_new_custom ()

    GstMessage*         gst_message_new_custom              (GstMessageType type,
                                                             GstObject *src,
                                                             GstStructure *structure);

Create a new custom-typed message. This can be used for anything not handled by other message-specific functions to pass a message to the app. The structure field can be NULL.

`type` : | The GstMessageType to distinguish messages
`src` : | The object originating the message.
`structure` : | The structure for the message. The message will take ownership of the structure.
Returns : | The new message. MT safe.

### gst_message_new_segment_start ()

    GstMessage*         gst_message_new_segment_start       (GstObject *src,
                                                             GstFormat format,
                                                             gint64 position);

Create a new segment message. This message is posted by elements that start playback of a segment as a result of a segment seek. This message is not received by the application but is used for maintenance reasons in container elements.

`src` : | The object originating the message.
`format` : | The format of the position being played
`position` : | The position of the segment being played
Returns : | The new segment start message. MT safe.

### gst_message_parse_segment_start ()

    void                gst_message_parse_segment_start     (GstMessage *message,
                                                             GstFormat *format,
                                                             gint64 *position);

Extracts the position and format from the segment start message.

MT safe.

`message` : | A valid GstMessage of type GST_MESSAGE_SEGMENT_START.
`format` : | Result location for the format, or NULL
`position` : | Result location for the position, or NULL

### gst_message_new_segment_done ()

    GstMessage*         gst_message_new_segment_done        (GstObject *src,
                                                             GstFormat format,
                                                             gint64 position);

Create a new segment done message. This message is posted by elements that finish playback of a segment as a result of a segment seek. This message is received by the application after all elements that posted a segment_start have posted the segment_done.

`src` : | The object originating the message.
`format` : | The format of the position being done
`position` : | The position of the segment being done
Returns : | The new segment done message. MT safe.

### gst_message_parse_segment_done ()

    void                gst_message_parse_segment_done      (GstMessage *message,
                                                             GstFormat *format,
                                                             gint64 *position);

Extracts the position and format from the segment start message.

MT safe.

`message` : | A valid GstMessage of type GST_MESSAGE_SEGMENT_DONE.
`format` : | Result location for the format, or NULL
`position` : | Result location for the position, or NULL

### gst_message_new_duration ()

    GstMessage*         gst_message_new_duration            (GstObject *src,
                                                             GstFormat format,
                                                             gint64 duration);

Create a new duration message. This message is posted by elements that know the duration of a stream in a specific format. This message is received by bins and is used to calculate the total duration of a pipeline. Elements may post a duration message with a duration of GST_CLOCK_TIME_NONE to indicate that the duration has changed and the cached duration should be discarded. The new duration can then be retrieved via a query.

`src` : | The object originating the message.
`format` : | The format of the duration
`duration` : | The new duration
Returns : | The new duration message. MT safe.

### gst_message_parse_duration ()

    void                gst_message_parse_duration          (GstMessage *message,
                                                             GstFormat *format,
                                                             gint64 *duration);

Extracts the duration and format from the duration message. The duration might be GST_CLOCK_TIME_NONE, which indicates that the duration has changed. Applications should always use a query to retrieve the duration of a pipeline.

MT safe.

`message` : | A valid GstMessage of type GST_MESSAGE_DURATION.
`format` : | Result location for the format, or NULL
`duration` : | Result location for the duration, or NULL

### gst_message_new_latency ()

    GstMessage*         gst_message_new_latency             (GstObject *src);

This message can be posted by elements when their latency requirements have changed.

`src` : | The object originating the message.
Returns : | The new latency message. MT safe.

Since 0.10.12

### gst_message_new_async_start ()

    GstMessage*         gst_message_new_async_start         (GstObject *src,
                                                             gboolean new_base_time);

This message is posted by elements when they start an ASYNC state change. `new_base_time` is set to TRUE when the element lost its state when it was PLAYING.

`src` : | The object originating the message.
`new_base_time` : | if a new base_time should be set on the element
Returns : | The new async_start message. MT safe.

Since 0.10.13

### gst_message_parse_async_start ()

    void                gst_message_parse_async_start       (GstMessage *message,
                                                             gboolean *new_base_time);

Extract the new_base_time from the async_start message.

MT safe.

`message` : | A valid GstMessage of type GST_MESSAGE_ASYNC_DONE.
`new_base_time` : | Result location for the new_base_time or NULL

Since 0.10.13

### gst_message_new_async_done ()

    GstMessage*         gst_message_new_async_done          (GstObject *src);

The message is posted when elements completed an ASYNC state change.

`src` : | The object originating the message.
Returns : | The new async_done message. MT safe.

Since 0.10.13

## See Also

GstBus, GstMiniObject, GstElement