GstEvent

## GstEvent GstEvent — Structure describing events that are passed up and down a pipeline |

## Synopsis

    #include <gst/gst.h>

    struct              GstEvent;
    enum                GstEventTypeFlags;
    #define             GST_EVENT_TYPE_BOTH
    #define             GST_EVENT_MAKE_TYPE                 (num,
                                                             flags)
    enum                GstEventType;
    #define             GST_EVENT_TYPE                      (event)
    #define             GST_EVENT_TYPE_NAME                 (event)
    #define             GST_EVENT_TIMESTAMP                 (event)
    #define             GST_EVENT_SEQNUM                    (event)
    #define             GST_EVENT_IS_UPSTREAM               (ev)
    #define             GST_EVENT_IS_DOWNSTREAM             (ev)
    #define             GST_EVENT_IS_SERIALIZED             (ev)
    #define             GST_EVENT_IS_STICKY                 (ev)
    GstEventTypeFlags   gst_event_type_get_flags            (GstEventType type);
    const gchar *       gst_event_type_get_name             (GstEventType type);
    GQuark              gst_event_type_to_quark             (GstEventType type);
    GstEvent *          gst_event_ref                       (GstEvent *event);
    void                gst_event_unref                     (GstEvent *event);
    gboolean            gst_event_replace                   (GstEvent **old_event,
                                                             GstEvent *new_event);
    GstEvent *          gst_event_copy                      (const GstEvent *event);
    GstEvent *          gst_event_steal                     (GstEvent **old_event);
    gboolean            gst_event_take                      (GstEvent **old_event,
                                                             GstEvent *new_event);
    #define             gst_event_is_writable               (ev)
    #define             gst_event_make_writable             (ev)
    GstStructure *      gst_event_writable_structure        (GstEvent *event);
    GstEvent *          gst_event_new_custom                (GstEventType type,
                                                             GstStructure *structure);
    const GstStructure * gst_event_get_structure            (GstEvent *event);
    gboolean            gst_event_has_name                  (GstEvent *event,
                                                             const gchar *name);
    guint32             gst_event_get_seqnum                (GstEvent *event);
    void                gst_event_set_seqnum                (GstEvent *event,
                                                             guint32 seqnum);
    GstEvent *          gst_event_new_flush_start           (void);
    GstEvent *          gst_event_new_flush_stop            (gboolean reset_time);
    void                gst_event_parse_flush_stop          (GstEvent *event,
                                                             gboolean *reset_time);
    GstEvent *          gst_event_new_eos                   (void);
    GstEvent *          gst_event_new_gap                   (GstClockTime timestamp,
                                                             GstClockTime duration);
    void                gst_event_parse_gap                 (GstEvent *event,
                                                             GstClockTime *timestamp,
                                                             GstClockTime *duration);
    GstEvent *          gst_event_new_stream_start          (const gchar *stream_id);
    void                gst_event_parse_stream_start        (GstEvent *event,
                                                             const gchar **stream_id);
    void                gst_event_set_stream_flags          (GstEvent *event,
                                                             GstStreamFlags flags);
    void                gst_event_parse_stream_flags        (GstEvent *event,
                                                             GstStreamFlags *flags);
    void                gst_event_set_group_id              (GstEvent *event,
                                                             guint group_id);
    gboolean            gst_event_parse_group_id            (GstEvent *event,
                                                             guint *group_id);
    GstEvent *          gst_event_new_segment               (const GstSegment *segment);
    void                gst_event_parse_segment             (GstEvent *event,
                                                             const GstSegment **segment);
    void                gst_event_copy_segment              (GstEvent *event,
                                                             GstSegment *segment);
    GstEvent *          gst_event_new_tag                   (GstTagList *taglist);
    void                gst_event_parse_tag                 (GstEvent *event,
                                                             GstTagList **taglist);
    GstEvent *          gst_event_new_buffer_size           (GstFormat format,
                                                             gint64 minsize,
                                                             gint64 maxsize,
                                                             gboolean async);
    void                gst_event_parse_buffer_size         (GstEvent *event,
                                                             GstFormat *format,
                                                             gint64 *minsize,
                                                             gint64 *maxsize,
                                                             gboolean *async);
    enum                GstQOSType;
    GstEvent *          gst_event_new_qos                   (GstQOSType type,
                                                             gdouble proportion,
                                                             GstClockTimeDiff diff,
                                                             GstClockTime timestamp);
    void                gst_event_parse_qos                 (GstEvent *event,
                                                             GstQOSType *type,
                                                             gdouble *proportion,
                                                             GstClockTimeDiff *diff,
                                                             GstClockTime *timestamp);
    enum                GstSeekType;
    enum                GstSeekFlags;
    GstEvent *          gst_event_new_seek                  (gdouble rate,
                                                             GstFormat format,
                                                             GstSeekFlags flags,
                                                             GstSeekType start_type,
                                                             gint64 start,
                                                             GstSeekType stop_type,
                                                             gint64 stop);
    void                gst_event_parse_seek                (GstEvent *event,
                                                             gdouble *rate,
                                                             GstFormat *format,
                                                             GstSeekFlags *flags,
                                                             GstSeekType *start_type,
                                                             gint64 *start,
                                                             GstSeekType *stop_type,
                                                             gint64 *stop);
    GstEvent *          gst_event_new_navigation            (GstStructure *structure);
    GstEvent *          gst_event_new_latency               (GstClockTime latency);
    void                gst_event_parse_latency             (GstEvent *event,
                                                             GstClockTime *latency);
    GstEvent *          gst_event_new_step                  (GstFormat format,
                                                             guint64 amount,
                                                             gdouble rate,
                                                             gboolean flush,
                                                             gboolean intermediate);
    void                gst_event_parse_step                (GstEvent *event,
                                                             GstFormat *format,
                                                             guint64 *amount,
                                                             gdouble *rate,
                                                             gboolean *flush,
                                                             gboolean *intermediate);
    GstEvent *          gst_event_new_sink_message          (const gchar *name,
                                                             GstMessage *msg);
    void                gst_event_parse_sink_message        (GstEvent *event,
                                                             GstMessage **msg);
    GstEvent *          gst_event_new_reconfigure           (void);
    GstEvent *          gst_event_new_caps                  (GstCaps *caps);
    void                gst_event_parse_caps                (GstEvent *event,
                                                             GstCaps **caps);
    GstEvent *          gst_event_new_toc                   (GstToc *toc,
                                                             gboolean updated);
    void                gst_event_parse_toc                 (GstEvent *event,
                                                             GstToc **toc,
                                                             gboolean *updated);
    GstEvent *          gst_event_new_toc_select            (const gchar *uid);
    void                gst_event_parse_toc_select          (GstEvent *event,
                                                             gchar **uid);
    GstEvent *          gst_event_new_segment_done          (GstFormat format,
                                                             gint64 position);
    void                gst_event_parse_segment_done        (GstEvent *event,
                                                             GstFormat *format,
                                                             gint64 *position);

## Description

The event class provides factory methods to construct events for sending and functions to query (parse) received events.

Events are usually created with gst_event_new_*() which takes event-type specific parameters as arguments. To send an event application will usually use `gst_element_send_event()` and elements will use `gst_pad_send_event()` or `gst_pad_push_event()`. The event should be unreffed with `gst_event_unref()` if it has not been sent.

Events that have been received can be parsed with their respective gst_event_parse_*() functions. It is valid to pass `NULL` for unwanted details.

Events are passed between elements in parallel to the data stream. Some events are serialized with buffers, others are not. Some events only travel downstream, others only upstream. Some events can travel both upstream and downstream.

The events are used to signal special conditions in the datastream such as EOS (end of stream) or the start of a new stream-segment. Events are also used to flush the pipeline of any pending data.

Most of the event API is used inside plugins. Applications usually only construct and use seek events. To do that `gst_event_new_seek()` is used to create a seek event. It takes the needed parameters to specify seeking time and mode.

Example 8. performing a seek on a pipeline

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    GstEvent *event;
    gboolean result;
    ...
    // construct a seek event to play the media from second 2 to 5, flush
    // the pipeline to decrease latency.
    event = gst_event_new_seek (1.0,
       GST_FORMAT_TIME,
       GST_SEEK_FLAG_FLUSH,
       GST_SEEK_TYPE_SET, 2 * GST_SECOND,
       GST_SEEK_TYPE_SET, 5 * GST_SECOND);
    ...
    result = gst_element_send_event (pipeline, event);
    if (!result)
      g_warning ("seek failed");
    ...

Last reviewed on 2012-03-28 (0.11.3)

## Details

### struct GstEvent

    struct GstEvent {
      GstMiniObject mini_object;

      GstEventType  type;
      guint64       timestamp;
      guint32       seqnum;
    };

A GstEvent.

GstMiniObject `mini_object`; | the parent structure
GstEventType `type`; | the GstEventType of the event
guint64 `timestamp`; | the timestamp of the event
guint32 `seqnum`; | the sequence number of the event

### enum GstEventTypeFlags

    typedef enum {
      GST_EVENT_TYPE_UPSTREAM       = 1 << 0,
      GST_EVENT_TYPE_DOWNSTREAM     = 1 << 1,
      GST_EVENT_TYPE_SERIALIZED     = 1 << 2,
      GST_EVENT_TYPE_STICKY         = 1 << 3,
      GST_EVENT_TYPE_STICKY_MULTI   = 1 << 4
    } GstEventTypeFlags;

GstEventTypeFlags indicate the aspects of the different GstEventType values. You can get the type flags of a GstEventType with the `gst_event_type_get_flags()` function.

`GST_EVENT_TYPE_UPSTREAM` | Set if the event can travel upstream.
`GST_EVENT_TYPE_DOWNSTREAM` | Set if the event can travel downstream.
`GST_EVENT_TYPE_SERIALIZED` | Set if the event should be serialized with data flow.
`GST_EVENT_TYPE_STICKY` | Set if the event is sticky on the pads.
`GST_EVENT_TYPE_STICKY_MULTI` | Multiple sticky events can be on a pad, each identified by the event name.

### GST_EVENT_TYPE_BOTH

    #define             GST_EVENT_TYPE_BOTH

The same thing as GST_EVENT_TYPE_UPSTREAM | GST_EVENT_TYPE_DOWNSTREAM.

### GST_EVENT_MAKE_TYPE()

    #define             GST_EVENT_MAKE_TYPE(num,flags)

when making custom event types, use this macro with the num and the given flags

`num` : | the event number to create
`flags` : | the event flags

### enum GstEventType

    typedef enum {
      GST_EVENT_UNKNOWN               = GST_EVENT_MAKE_TYPE (0, 0),

      /* bidirectional events */
      GST_EVENT_FLUSH_START           = GST_EVENT_MAKE_TYPE (10, FLAG(BOTH)),
      GST_EVENT_FLUSH_STOP            = GST_EVENT_MAKE_TYPE (20, FLAG(BOTH) | FLAG(SERIALIZED)),

      /* downstream serialized events */
      GST_EVENT_STREAM_START          = GST_EVENT_MAKE_TYPE (40, FLAG(DOWNSTREAM) | FLAG(SERIALIZED) | FLAG(STICKY)),
      GST_EVENT_CAPS                  = GST_EVENT_MAKE_TYPE (50, FLAG(DOWNSTREAM) | FLAG(SERIALIZED) | FLAG(STICKY)),
      GST_EVENT_SEGMENT               = GST_EVENT_MAKE_TYPE (70, FLAG(DOWNSTREAM) | FLAG(SERIALIZED) | FLAG(STICKY)),
      GST_EVENT_TAG                   = GST_EVENT_MAKE_TYPE (80, FLAG(DOWNSTREAM) | FLAG(SERIALIZED) | FLAG(STICKY) | FLAG(STICKY_MULTI)),
      GST_EVENT_BUFFERSIZE            = GST_EVENT_MAKE_TYPE (90, FLAG(DOWNSTREAM) | FLAG(SERIALIZED) | FLAG(STICKY)),
      GST_EVENT_SINK_MESSAGE          = GST_EVENT_MAKE_TYPE (100, FLAG(DOWNSTREAM) | FLAG(SERIALIZED) | FLAG(STICKY) | FLAG(STICKY_MULTI)),
      GST_EVENT_EOS                   = GST_EVENT_MAKE_TYPE (110, FLAG(DOWNSTREAM) | FLAG(SERIALIZED) | FLAG(STICKY)),
      GST_EVENT_TOC                   = GST_EVENT_MAKE_TYPE (120, FLAG(DOWNSTREAM) | FLAG(SERIALIZED) | FLAG(STICKY) | FLAG(STICKY_MULTI)),

      /* non-sticky downstream serialized */
      GST_EVENT_SEGMENT_DONE          = GST_EVENT_MAKE_TYPE (150, FLAG(DOWNSTREAM) | FLAG(SERIALIZED)),
      GST_EVENT_GAP                   = GST_EVENT_MAKE_TYPE (160, FLAG(DOWNSTREAM) | FLAG(SERIALIZED)),

      /* upstream events */
      GST_EVENT_QOS                   = GST_EVENT_MAKE_TYPE (190, FLAG(UPSTREAM)),
      GST_EVENT_SEEK                  = GST_EVENT_MAKE_TYPE (200, FLAG(UPSTREAM)),
      GST_EVENT_NAVIGATION            = GST_EVENT_MAKE_TYPE (210, FLAG(UPSTREAM)),
      GST_EVENT_LATENCY               = GST_EVENT_MAKE_TYPE (220, FLAG(UPSTREAM)),
      GST_EVENT_STEP                  = GST_EVENT_MAKE_TYPE (230, FLAG(UPSTREAM)),
      GST_EVENT_RECONFIGURE           = GST_EVENT_MAKE_TYPE (240, FLAG(UPSTREAM)),
      GST_EVENT_TOC_SELECT            = GST_EVENT_MAKE_TYPE (250, FLAG(UPSTREAM)),

      /* custom events start here */
      GST_EVENT_CUSTOM_UPSTREAM          = GST_EVENT_MAKE_TYPE (270, FLAG(UPSTREAM)),
      GST_EVENT_CUSTOM_DOWNSTREAM        = GST_EVENT_MAKE_TYPE (280, FLAG(DOWNSTREAM) | FLAG(SERIALIZED)),
      GST_EVENT_CUSTOM_DOWNSTREAM_OOB    = GST_EVENT_MAKE_TYPE (290, FLAG(DOWNSTREAM)),
      GST_EVENT_CUSTOM_DOWNSTREAM_STICKY = GST_EVENT_MAKE_TYPE (300, FLAG(DOWNSTREAM) | FLAG(SERIALIZED) | FLAG(STICKY) | FLAG(STICKY_MULTI)),
      GST_EVENT_CUSTOM_BOTH              = GST_EVENT_MAKE_TYPE (310, FLAG(BOTH) | FLAG(SERIALIZED)),
      GST_EVENT_CUSTOM_BOTH_OOB          = GST_EVENT_MAKE_TYPE (320, FLAG(BOTH))
    } GstEventType;

GstEventType lists the standard event types that can be sent in a pipeline.

The custom event types can be used for private messages between elements that can't be expressed using normal GStreamer buffer passing semantics. Custom events carry an arbitrary GstStructure. Specific custom events are distinguished by the name of the structure.

`GST_EVENT_UNKNOWN` | unknown event.
`GST_EVENT_FLUSH_START` | Start a flush operation. This event clears all data from the pipeline and unblock all streaming threads.
`GST_EVENT_FLUSH_STOP` | Stop a flush operation. This event resets the running-time of the pipeline.
`GST_EVENT_STREAM_START` | Event to mark the start of a new stream. Sent before any other serialized event and only sent at the start of a new stream, not after flushing seeks.
`GST_EVENT_CAPS` | GstCaps event. Notify the pad of a new media type.
`GST_EVENT_SEGMENT` | A new media segment follows in the dataflow. The segment events contains information for clipping buffers and converting buffer timestamps to running-time and stream-time.
`GST_EVENT_TAG` | A new set of metadata tags has been found in the stream.
`GST_EVENT_BUFFERSIZE` | Notification of buffering requirements. Currently not used yet.
`GST_EVENT_SINK_MESSAGE` | An event that sinks turn into a message. Used to send messages that should be emitted in sync with rendering.
`GST_EVENT_EOS` | End-Of-Stream. No more data is to be expected to follow without a SEGMENT event.
`GST_EVENT_TOC` | An event which indicates that a new table of contents (TOC) was found or updated.
`GST_EVENT_SEGMENT_DONE` | Marks the end of a segment playback.
`GST_EVENT_GAP` | Marks a gap in the datastream.
`GST_EVENT_QOS` | A quality message. Used to indicate to upstream elements that the downstream elements should adjust their processing rate.
`GST_EVENT_SEEK` | A request for a new playback position and rate.
`GST_EVENT_NAVIGATION` | Navigation events are usually used for communicating user requests, such as mouse or keyboard movements, to upstream elements.
`GST_EVENT_LATENCY` | Notification of new latency adjustment. Sinks will use the latency information to adjust their synchronisation.
`GST_EVENT_STEP` | A request for stepping through the media. Sinks will usually execute the step operation.
`GST_EVENT_RECONFIGURE` | A request for upstream renegotiating caps and reconfiguring.
`GST_EVENT_TOC_SELECT` | A request for a new playback position based on TOC entry's UID.
`GST_EVENT_CUSTOM_UPSTREAM` | Upstream custom event
`GST_EVENT_CUSTOM_DOWNSTREAM` | Downstream custom event that travels in the data flow.
`GST_EVENT_CUSTOM_DOWNSTREAM_OOB` | Custom out-of-band downstream event.
`GST_EVENT_CUSTOM_DOWNSTREAM_STICKY` | Custom sticky downstream event.
`GST_EVENT_CUSTOM_BOTH` | Custom upstream or downstream event. In-band when travelling downstream.
`GST_EVENT_CUSTOM_BOTH_OOB` | Custom upstream or downstream out-of-band event.

### GST_EVENT_TYPE()

    #define GST_EVENT_TYPE(event)           (GST_EVENT_CAST(event)->type)

Get the GstEventType of the event.

`event` : | the event to query

### GST_EVENT_TYPE_NAME()

    #define GST_EVENT_TYPE_NAME(event)      (gst_event_type_get_name(GST_EVENT_TYPE(event)))

Get a constant string representation of the GstEventType of the event.

`event` : | the event to query

### GST_EVENT_TIMESTAMP()

    #define GST_EVENT_TIMESTAMP(event)      (GST_EVENT_CAST(event)->timestamp)

Get the GstClockTime timestamp of the event. This is the time when the event was created.

`event` : | the event to query

### GST_EVENT_SEQNUM()

    #define GST_EVENT_SEQNUM(event)         (GST_EVENT_CAST(event)->seqnum)

The sequence number of `event`.

`event` : | the event to query

### GST_EVENT_IS_UPSTREAM()

    #define GST_EVENT_IS_UPSTREAM(ev)       !!(GST_EVENT_TYPE (ev) & GST_EVENT_TYPE_UPSTREAM)

Check if an event can travel upstream.

`ev` : | the event to query

### GST_EVENT_IS_DOWNSTREAM()

    #define GST_EVENT_IS_DOWNSTREAM(ev)     !!(GST_EVENT_TYPE (ev) & GST_EVENT_TYPE_DOWNSTREAM)

Check if an event can travel downstream.

`ev` : | the event to query

### GST_EVENT_IS_SERIALIZED()

    #define GST_EVENT_IS_SERIALIZED(ev)     !!(GST_EVENT_TYPE (ev) & GST_EVENT_TYPE_SERIALIZED)

Check if an event is serialized with the data stream.

`ev` : | the event to query

### GST_EVENT_IS_STICKY()

    #define GST_EVENT_IS_STICKY(ev)     !!(GST_EVENT_TYPE (ev) & GST_EVENT_TYPE_STICKY)

Check if an event is sticky on the pads.

`ev` : | the event to query

### gst_event_type_get_flags ()

    GstEventTypeFlags   gst_event_type_get_flags            (GstEventType type);

Gets the GstEventTypeFlags associated with `type`.

`type` : | a GstEventType
Returns : | a GstEventTypeFlags.

### gst_event_type_get_name ()

    const gchar *       gst_event_type_get_name             (GstEventType type);

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

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

### gst_event_type_to_quark ()

    GQuark              gst_event_type_to_quark             (GstEventType type);

Get the unique quark for the given event type.

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

### gst_event_ref ()

    GstEvent *          gst_event_ref                       (GstEvent *event);

Increase the refcount of this event.

`event` : | The event to refcount
Returns : | `event` (for convenience when doing assignments). [transfer full]

### gst_event_unref ()

    void                gst_event_unref                     (GstEvent *event);

Decrease the refcount of an event, freeing it if the refcount reaches 0.

`event` : | the event to refcount. [transfer full]

### gst_event_replace ()

    gboolean            gst_event_replace                   (GstEvent **old_event,
                                                             GstEvent *new_event);

Modifies a pointer to a GstEvent to point to a different GstEvent. The modification is done atomically (so this is useful for ensuring thread safety in some cases), and the reference counts are updated appropriately (the old event is unreffed, the new one is reffed).

Either `new_event` or the GstEvent pointed to by `old_event` may be NULL.

`old_event` : | pointer to a pointer to a GstEvent to be replaced. [inout][transfer full]
`new_event` : | pointer to a GstEvent that will replace the event pointed to by `old_event`. [allow-none][transfer none]
Returns : | TRUE if `new_event` was different from `old_event`

### gst_event_copy ()

    GstEvent *          gst_event_copy                      (const GstEvent *event);

Copy the event using the event specific copy function.

`event` : | The event to copy
Returns : | the new event. [transfer full]

### gst_event_steal ()

    GstEvent *          gst_event_steal                     (GstEvent **old_event);

Atomically replace the GstEvent pointed to by `old_event` with NULL and return the original event.

`old_event` : | pointer to a pointer to a GstEvent to be stolen. [inout][transfer full]
Returns : | the GstEvent that was in `old_event`

### gst_event_take ()

    gboolean            gst_event_take                      (GstEvent **old_event,
                                                             GstEvent *new_event);

Modifies a pointer to a GstEvent to point to a different GstEvent. This function is similar to `gst_event_replace()` except that it takes ownership of `new_event`.

Either `new_event` or the GstEvent pointed to by `old_event` may be NULL.

`old_event` : | pointer to a pointer to a GstEvent to be stolen. [inout][transfer full]
`new_event` : | pointer to a GstEvent that will replace the event pointed to by `old_event`. [allow-none][transfer full]
Returns : | TRUE if `new_event` was different from `old_event`

### gst_event_is_writable()

    #define         gst_event_is_writable(ev)     gst_mini_object_is_writable (GST_MINI_OBJECT_CAST (ev))

Tests if you can safely write data into a event's structure or validly modify the seqnum and timestamp field.

`ev` : | a GstEvent

### gst_event_make_writable()

    #define         gst_event_make_writable(ev)   GST_EVENT_CAST (gst_mini_object_make_writable (GST_MINI_OBJECT_CAST (ev)))

Makes a writable event from the given event. If the source event is already writable, this will simply return the same event. A copy will otherwise be made using `gst_event_copy()`.

`ev` : | a GstEvent. [transfer full]
Returns : | a writable event which may or may not be the same as `ev`. [transfer full]

### gst_event_writable_structure ()

    GstStructure *      gst_event_writable_structure        (GstEvent *event);

Get a writable version of the structure.

`event` : | The GstEvent.
Returns : | The structure of the event. The structure is still owned by the event, which means that you should not free it and that the pointer becomes invalid when you free the event. This function checks if `event` is writable and will never return NULL. MT safe.

### gst_event_new_custom ()

    GstEvent *          gst_event_new_custom                (GstEventType type,
                                                             GstStructure *structure);

Create a new custom-typed event. This can be used for anything not handled by other event-specific functions to pass an event to another element.

Make sure to allocate an event type with the GST_EVENT_MAKE_TYPE macro, assigning a free number and filling in the correct direction and serialization flags.

New custom events can also be created by subclassing the event type if needed.

`type` : | The type of the new event
`structure` : | the structure for the event. The event will take ownership of the structure. [transfer full]
Returns : | the new custom event. [transfer full]

### gst_event_get_structure ()

    const GstStructure * gst_event_get_structure            (GstEvent *event);

Access the structure of the event.

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

### gst_event_has_name ()

    gboolean            gst_event_has_name                  (GstEvent *event,
                                                             const gchar *name);

Checks if `event` has the given `name`. This function is usually used to check the name of a custom event.

`event` : | The GstEvent.
`name` : | name to check
Returns : | `TRUE` if `name` matches the name of the event structure.

### gst_event_get_seqnum ()

    guint32             gst_event_get_seqnum                (GstEvent *event);

Retrieve the sequence number of a event.

Events have ever-incrementing sequence numbers, which may also be set explicitly via `gst_event_set_seqnum()`. Sequence numbers are typically used to indicate that a event corresponds to some other set of events or messages, for example an EOS event corresponding to a SEEK event. It is considered good practice to make this correspondence when possible, though it is not required.

Note that events and messages share the same sequence number incrementor; two events or messages will never have the same sequence number unless that correspondence was made explicitly.

`event` : | A GstEvent.
Returns : | The event's sequence number. MT safe.

### gst_event_set_seqnum ()

    void                gst_event_set_seqnum                (GstEvent *event,
                                                             guint32 seqnum);

Set the sequence number of a event.

This function might be called by the creator of a event to indicate that the event relates to other events or messages. See `gst_event_get_seqnum()` for more information.

MT safe.

`event` : | A GstEvent.
`seqnum` : | A sequence number.

### gst_event_new_flush_start ()

    GstEvent *          gst_event_new_flush_start           (void);

Allocate a new flush start event. The flush start event can be sent upstream and downstream and travels out-of-bounds with the dataflow.

It marks pads as being flushing and will make them return GST_FLOW_FLUSHING when used for data flow with `gst_pad_push()`, `gst_pad_chain()`, `gst_pad_get_range()` and `gst_pad_pull_range()`. Any event (except a GST_EVENT_FLUSH_STOP) received on a flushing pad will return `FALSE` immediately.

Elements should unlock any blocking functions and exit their streaming functions as fast as possible when this event is received.

This event is typically generated after a seek to flush out all queued data in the pipeline so that the new media is played as soon as possible.

Returns : | a new flush start event. [transfer full]

### gst_event_new_flush_stop ()

    GstEvent *          gst_event_new_flush_stop            (gboolean reset_time);

Allocate a new flush stop event. The flush stop event can be sent upstream and downstream and travels serialized with the dataflow. It is typically sent after sending a FLUSH_START event to make the pads accept data again.

Elements can process this event synchronized with the dataflow since the preceeding FLUSH_START event stopped the dataflow.

This event is typically generated to complete a seek and to resume dataflow.

`reset_time` : | if time should be reset
Returns : | a new flush stop event. [transfer full]

### gst_event_parse_flush_stop ()

    void                gst_event_parse_flush_stop          (GstEvent *event,
                                                             gboolean *reset_time);

Parse the FLUSH_STOP event and retrieve the `reset_time` member.

`event` : | The event to parse
`reset_time` : | if time should be reset. [out]

### gst_event_new_eos ()

    GstEvent *          gst_event_new_eos                   (void);

Create a new EOS event. The eos event can only travel downstream synchronized with the buffer flow. Elements that receive the EOS event on a pad can return GST_FLOW_EOS as a GstFlowReturn when data after the EOS event arrives.

The EOS event will travel down to the sink elements in the pipeline which will then post the GST_MESSAGE_EOS on the bus after they have finished playing any buffered data.

When all sinks have posted an EOS message, an EOS message is forwarded to the application.

The EOS event itself will not cause any state transitions of the pipeline.

Returns : | the new EOS event. [transfer full]

### gst_event_new_gap ()

    GstEvent *          gst_event_new_gap                   (GstClockTime timestamp,
                                                             GstClockTime duration);

Create a new GAP event. A gap event can be thought of as conceptually equivalent to a buffer to signal that there is no data for a certain amount of time. This is useful to signal a gap to downstream elements which may wait for data, such as muxers or mixers or overlays, especially for sparse streams such as subtitle streams.

`timestamp` : | the start time (pts) of the gap
`duration` : | the duration of the gap
Returns : | the new GAP event. [transfer full]

### gst_event_parse_gap ()

    void                gst_event_parse_gap                 (GstEvent *event,
                                                             GstClockTime *timestamp,
                                                             GstClockTime *duration);

Extract timestamp and duration from a new GAP event.

`event` : | a GstEvent of type GST_EVENT_GAP
`timestamp` : | location where to store the start time (pts) of the gap, or `NULL`. [out][allow-none]
`duration` : | location where to store the duration of the gap, or `NULL`. [out][allow-none]

### gst_event_new_stream_start ()

    GstEvent *          gst_event_new_stream_start          (const gchar *stream_id);

Create a new STREAM_START event. The stream start event can only travel downstream synchronized with the buffer flow. It is expected to be the first event that is sent for a new stream.

Source elements, demuxers and other elements that create new streams are supposed to send this event as the first event of a new stream. It should not be send after a flushing seek or in similar situations and is used to mark the beginning of a new logical stream. Elements combining multiple streams must ensure that this event is only forwarded downstream once and not for every single input stream.

The `stream_id` should be a unique string that consists of the upstream stream-id, / as separator and a unique stream-id for this specific stream. A new stream-id should only be created for a stream if the upstream stream is split into (potentially) multiple new streams, e.g. in a demuxer, but not for every single element in the pipeline. `gst_pad_create_stream_id()` or `gst_pad_create_stream_id_printf()` can be used to create a stream-id.

`stream_id` : | Identifier for this stream
Returns : | the new STREAM_START event. [transfer full]

### gst_event_parse_stream_start ()

    void                gst_event_parse_stream_start        (GstEvent *event,
                                                             const gchar **stream_id);

Parse a stream-id `event` and store the result in the given `stream_id` location. The string stored in `stream_id` must not be modified and will remain valid only until `event` gets freed. Make a copy if you want to modify it or store it for later use.

`event` : | a stream-start event.
`stream_id` : | pointer to store the stream-id. [out][transfer none]

### gst_event_set_stream_flags ()

    void                gst_event_set_stream_flags          (GstEvent *event,
                                                             GstStreamFlags flags);

`event` : | a stream-start event
`flags` : | the stream flags to set

Since 1.2

### gst_event_parse_stream_flags ()

    void                gst_event_parse_stream_flags        (GstEvent *event,
                                                             GstStreamFlags *flags);

`event` : | a stream-start event
`flags` : | address of variable where to store the stream flags. [out]

Since 1.2

### gst_event_set_group_id ()

    void                gst_event_set_group_id              (GstEvent *event,
                                                             guint group_id);

All streams that have the same group id are supposed to be played together, i.e. all streams inside a container file should have the same group id but different stream ids. The group id should change each time the stream is started, resulting in different group ids each time a file is played for example.

Use `gst_util_group_id_next()` to get a new group id.

`event` : | a stream-start event
`group_id` : | the group id to set

Since 1.2

### gst_event_parse_group_id ()

    gboolean            gst_event_parse_group_id            (GstEvent *event,
                                                             guint *group_id);

`event` : | a stream-start event
`group_id` : | address of variable where to store the group id. [out]
Returns : | `TRUE` if a group id was set on the event and could be parsed, `FALSE` otherwise.

Since 1.2

### gst_event_new_segment ()

    GstEvent *          gst_event_new_segment               (const GstSegment *segment);

Create a new SEGMENT event for `segment`. The segment event can only travel downstream synchronized with the buffer flow and contains timing information and playback properties for the buffers that will follow.

The newsegment event marks the range of buffers to be processed. All data not within the segment range is not to be processed. This can be used intelligently by plugins to apply more efficient methods of skipping unneeded data. The valid range is expressed with the `start` and `stop` values.

The time value of the segment is used in conjunction with the start value to convert the buffer timestamps into the stream time. This is usually done in sinks to report the current stream_time. `time` represents the stream_time of a buffer carrying a timestamp of `start`. `time` cannot be -1.

`start` cannot be -1, `stop` can be -1. If there is a valid `stop` given, it must be greater or equal the `start`, including when the indicated playback `rate` is < 0.

The `applied_rate` value provides information about any rate adjustment that has already been made to the timestamps and content on the buffers of the stream. (`rate` * `applied_rate`) should always equal the rate that has been requested for playback. For example, if an element has an input segment with intended playback `rate` of 2.0 and applied_rate of 1.0, it can adjust incoming timestamps and buffer content by half and output a newsegment event with `rate` of 1.0 and `applied_rate` of 2.0

After a newsegment event, the buffer stream time is calculated with:

time + (TIMESTAMP(buf) - start) * ABS (rate * applied_rate)

`segment` : | a GstSegment. [transfer none]
Returns : | the new SEGMENT event. [transfer full]

### gst_event_parse_segment ()

    void                gst_event_parse_segment             (GstEvent *event,
                                                             const GstSegment **segment);

Parses a segment `event` and stores the result in the given `segment` location. `segment` remains valid only until the `event` is freed. Don't modify the segment and make a copy if you want to modify it or store it for later use.

`event` : | The event to parse
`segment` : | a pointer to a GstSegment. [out][transfer none]

### gst_event_copy_segment ()

    void                gst_event_copy_segment              (GstEvent *event,
                                                             GstSegment *segment);

Parses a segment `event` and copies the GstSegment into the location given by `segment`.

`event` : | The event to parse
`segment` : | a pointer to a GstSegment

### gst_event_new_tag ()

    GstEvent *          gst_event_new_tag                   (GstTagList *taglist);

Generates a metadata tag event from the given `taglist`.

The scope of the taglist specifies if the taglist applies to the complete medium or only to this specific stream. As the tag event is a sticky event, elements should merge tags received from upstream with a given scope with their own tags with the same scope and create a new tag event from it.

`taglist` : | metadata list. The event will take ownership of the taglist. [transfer full]
Returns : | a new GstEvent. [transfer full]

### gst_event_parse_tag ()

    void                gst_event_parse_tag                 (GstEvent *event,
                                                             GstTagList **taglist);

Parses a tag `event` and stores the results in the given `taglist` location. No reference to the taglist will be returned, it remains valid only until the `event` is freed. Don't modify or free the taglist, make a copy if you want to modify it or store it for later use.

`event` : | a tag event
`taglist` : | pointer to metadata list. [out][transfer none]

### gst_event_new_buffer_size ()

    GstEvent *          gst_event_new_buffer_size           (GstFormat format,
                                                             gint64 minsize,
                                                             gint64 maxsize,
                                                             gboolean async);

Create a new buffersize event. The event is sent downstream and notifies elements that they should provide a buffer of the specified dimensions.

When the `async` flag is set, a thread boundary is preferred.

`format` : | buffer format
`minsize` : | minimum buffer size
`maxsize` : | maximum buffer size
`async` : | thread behavior
Returns : | a new GstEvent. [transfer full]

### gst_event_parse_buffer_size ()

    void                gst_event_parse_buffer_size         (GstEvent *event,
                                                             GstFormat *format,
                                                             gint64 *minsize,
                                                             gint64 *maxsize,
                                                             gboolean *async);

Get the format, minsize, maxsize and async-flag in the buffersize event.

`event` : | The event to query
`format` : | A pointer to store the format in. [out]
`minsize` : | A pointer to store the minsize in. [out]
`maxsize` : | A pointer to store the maxsize in. [out]
`async` : | A pointer to store the async-flag in. [out]

### enum GstQOSType

    typedef enum {
      GST_QOS_TYPE_OVERFLOW        = 0,
      GST_QOS_TYPE_UNDERFLOW       = 1,
      GST_QOS_TYPE_THROTTLE        = 2
    } GstQOSType;

The different types of QoS events that can be given to the `gst_event_new_qos()` method.

`GST_QOS_TYPE_OVERFLOW` | The QoS event type that is produced when downstream elements are producing data too quickly and the element can't keep up processing the data. Upstream should reduce their processing rate. This type is also used when buffers arrive early or in time.
`GST_QOS_TYPE_UNDERFLOW` | The QoS event type that is produced when downstream elements are producing data too slowly and need to speed up their processing rate.
`GST_QOS_TYPE_THROTTLE` | The QoS event type that is produced when the application enabled throttling to limit the datarate.

### gst_event_new_qos ()

    GstEvent *          gst_event_new_qos                   (GstQOSType type,
                                                             gdouble proportion,
                                                             GstClockTimeDiff diff,
                                                             GstClockTime timestamp);

Allocate a new qos event with the given values. The QOS event is generated in an element that wants an upstream element to either reduce or increase its rate because of high/low CPU load or other resource usage such as network performance or throttling. Typically sinks generate these events for each buffer they receive.

`type` indicates the reason for the QoS event. GST_QOS_TYPE_OVERFLOW is used when a buffer arrived in time or when the sink cannot keep up with the upstream datarate. GST_QOS_TYPE_UNDERFLOW is when the sink is not receiving buffers fast enough and thus has to drop late buffers. GST_QOS_TYPE_THROTTLE is used when the datarate is artificially limited by the application, for example to reduce power consumption.

`proportion` indicates the real-time performance of the streaming in the element that generated the QoS event (usually the sink). The value is generally computed based on more long term statistics about the streams timestamps compared to the clock. A value < 1.0 indicates that the upstream element is producing data faster than real-time. A value > 1.0 indicates that the upstream element is not producing data fast enough. 1.0 is the ideal `proportion` value. The proportion value can safely be used to lower or increase the quality of the element.

`diff` is the difference against the clock in running time of the last buffer that caused the element to generate the QOS event. A negative value means that the buffer with `timestamp` arrived in time. A positive value indicates how late the buffer with `timestamp` was. When throttling is enabled, `diff` will be set to the requested throttling interval.

`timestamp` is the timestamp of the last buffer that cause the element to generate the QOS event. It is expressed in running time and thus an ever increasing value.

The upstream element can use the `diff` and `timestamp` values to decide whether to process more buffers. For possitive `diff`, all buffers with timestamp <= `timestamp` + `diff` will certainly arrive late in the sink as well. A (negative) `diff` value so that `timestamp` + `diff` would yield a result smaller than 0 is not allowed.

The application can use general event probes to intercept the QoS event and implement custom application specific QoS handling.

`type` : | the QoS type
`proportion` : | the proportion of the qos message
`diff` : | The time difference of the last Clock sync
`timestamp` : | The timestamp of the buffer
Returns : | a new QOS event. [transfer full]

### gst_event_parse_qos ()

    void                gst_event_parse_qos                 (GstEvent *event,
                                                             GstQOSType *type,
                                                             gdouble *proportion,
                                                             GstClockTimeDiff *diff,
                                                             GstClockTime *timestamp);

Get the type, proportion, diff and timestamp in the qos event. See `gst_event_new_qos()` for more information about the different QoS values.

`event` : | The event to query
`type` : | A pointer to store the QoS type in. [out]
`proportion` : | A pointer to store the proportion in. [out]
`diff` : | A pointer to store the diff in. [out]
`timestamp` : | A pointer to store the timestamp in. [out]

### enum GstSeekType

    typedef enum {
      /* one of these */
      GST_SEEK_TYPE_NONE            = 0,
      GST_SEEK_TYPE_SET             = 1,
      GST_SEEK_TYPE_END             = 2
    } GstSeekType;

The different types of seek events. When constructing a seek event with `gst_event_new_seek()` or when doing `gst_segment_do_seek()`.

`GST_SEEK_TYPE_NONE` | no change in position is required
`GST_SEEK_TYPE_SET` | absolute position is requested
`GST_SEEK_TYPE_END` | relative position to duration is requested

### enum GstSeekFlags

    typedef enum {
      GST_SEEK_FLAG_NONE            = 0,
      GST_SEEK_FLAG_FLUSH           = (1 << 0),
      GST_SEEK_FLAG_ACCURATE        = (1 << 1),
      GST_SEEK_FLAG_KEY_UNIT        = (1 << 2),
      GST_SEEK_FLAG_SEGMENT         = (1 << 3),
      GST_SEEK_FLAG_SKIP            = (1 << 4),
      GST_SEEK_FLAG_SNAP_BEFORE     = (1 << 5),
      GST_SEEK_FLAG_SNAP_AFTER      = (1 << 6),
      GST_SEEK_FLAG_SNAP_NEAREST    = GST_SEEK_FLAG_SNAP_BEFORE | GST_SEEK_FLAG_SNAP_AFTER,
      /* Careful to restart next flag with 1<<7 here */
    } GstSeekFlags;

Flags to be used with `gst_element_seek()` or `gst_event_new_seek()`. All flags can be used together.

A non flushing seek might take some time to perform as the currently playing data in the pipeline will not be cleared.

An accurate seek might be slower for formats that don't have any indexes or timestamp markers in the stream. Specifying this flag might require a complete scan of the file in those cases.

When performing a segment seek: after the playback of the segment completes, no EOS will be emmited by the element that performed the seek, but a GST_MESSAGE_SEGMENT_DONE message will be posted on the bus by the element. When this message is posted, it is possible to send a new seek event to continue playback. With this seek method it is possible to perform seamless looping or simple linear editing.

When doing fast forward (rate > 1.0) or fast reverse (rate < -1.0) trickmode playback, the `GST_SEEK_FLAG_SKIP` flag can be used to instruct decoders and demuxers to adjust the playback rate by skipping frames. This can improve performance and decrease CPU usage because not all frames need to be decoded.

The `GST_SEEK_FLAG_SNAP_BEFORE` flag can be used to snap to the previous relevant location, and the `GST_SEEK_FLAG_SNAP_AFTER` flag can be used to select the next relevant location. If KEY_UNIT is specified, the relevant location is a keyframe. If both flags are specified, the nearest of these locations will be selected. If none are specified, the implementation is free to select whichever it wants. The before and after here are in running time, so when playing backwards, the next location refers to the one that will played in next, and not the one that is located after in the actual source stream.

Also see part-seeking.txt in the GStreamer design documentation for more details on the meaning of these flags and the behaviour expected of elements that handle them.

`GST_SEEK_FLAG_NONE` | no flag
`GST_SEEK_FLAG_FLUSH` | flush pipeline
`GST_SEEK_FLAG_ACCURATE` | accurate position is requested, this might be considerably slower for some formats.
`GST_SEEK_FLAG_KEY_UNIT` | seek to the nearest keyframe. This might be faster but less accurate.
`GST_SEEK_FLAG_SEGMENT` | perform a segment seek.
`GST_SEEK_FLAG_SKIP` | when doing fast foward or fast reverse playback, allow elements to skip frames instead of generating all frames.
`GST_SEEK_FLAG_SNAP_BEFORE` | go to a location before the requested position, if KEY_UNIT this means the keyframe at or before the requested position the one at or before the seek target.
`GST_SEEK_FLAG_SNAP_AFTER` | go to a location after the requested position, if KEY_UNIT this means the keyframe at of after the requested position.
`GST_SEEK_FLAG_SNAP_NEAREST` | go to a position near the requested position, if KEY_UNIT this means the keyframe closest to the requested position, if both keyframes are at an equal distance, behaves like SNAP_BEFORE.

### gst_event_new_seek ()

    GstEvent *          gst_event_new_seek                  (gdouble rate,
                                                             GstFormat format,
                                                             GstSeekFlags flags,
                                                             GstSeekType start_type,
                                                             gint64 start,
                                                             GstSeekType stop_type,
                                                             gint64 stop);

Allocate a new seek event with the given parameters.

The seek event configures playback of the pipeline between `start` to `stop` at the speed given in `rate`, also called a playback segment. The `start` and `stop` values are expressed in `format`.

A `rate` of 1.0 means normal playback rate, 2.0 means double speed. Negatives values means backwards playback. A value of 0.0 for the rate is not allowed and should be accomplished instead by PAUSING the pipeline.

A pipeline has a default playback segment configured with a start position of 0, a stop position of -1 and a rate of 1.0. The currently configured playback segment can be queried with GST_QUERY_SEGMENT.

`start_type` and `stop_type` specify how to adjust the currently configured start and stop fields in playback segment. Adjustments can be made relative or absolute to the last configured values. A type of GST_SEEK_TYPE_NONE means that the position should not be updated.

When the rate is positive and `start` has been updated, playback will start from the newly configured start position.

For negative rates, playback will start from the newly configured stop position (if any). If the stop position is updated, it must be different from -1 (GST_CLOCK_TIME_NONE) for negative rates.

It is not possible to seek relative to the current playback position, to do this, PAUSE the pipeline, query the current playback position with GST_QUERY_POSITION and update the playback segment current position with a GST_SEEK_TYPE_SET to the desired position.

`rate` : | The new playback rate
`format` : | The format of the seek values
`flags` : | The optional seek flags
`start_type` : | The type and flags for the new start position
`start` : | The value of the new start position
`stop_type` : | The type and flags for the new stop position
`stop` : | The value of the new stop position
Returns : | a new seek event. [transfer full]

### gst_event_parse_seek ()

    void                gst_event_parse_seek                (GstEvent *event,
                                                             gdouble *rate,
                                                             GstFormat *format,
                                                             GstSeekFlags *flags,
                                                             GstSeekType *start_type,
                                                             gint64 *start,
                                                             GstSeekType *stop_type,
                                                             gint64 *stop);

Parses a seek `event` and stores the results in the given result locations.

`event` : | a seek event
`rate` : | result location for the rate. [out]
`format` : | result location for the stream format. [out]
`flags` : | result location for the GstSeekFlags. [out]
`start_type` : | result location for the GstSeekType of the start position. [out]
`start` : | result location for the start postion expressed in `format`. [out]
`stop_type` : | result location for the GstSeekType of the stop position. [out]
`stop` : | result location for the stop postion expressed in `format`. [out]

### gst_event_new_navigation ()

    GstEvent *          gst_event_new_navigation            (GstStructure *structure);

Create a new navigation event from the given description.

`structure` : | description of the event. The event will take ownership of the structure. [transfer full]
Returns : | a new GstEvent. [transfer full]

### gst_event_new_latency ()

    GstEvent *          gst_event_new_latency               (GstClockTime latency);

Create a new latency event. The event is sent upstream from the sinks and notifies elements that they should add an additional `latency` to the running time before synchronising against the clock.

The latency is mostly used in live sinks and is always expressed in the time format.

`latency` : | the new latency value
Returns : | a new GstEvent. [transfer full]

### gst_event_parse_latency ()

    void                gst_event_parse_latency             (GstEvent *event,
                                                             GstClockTime *latency);

Get the latency in the latency event.

`event` : | The event to query
`latency` : | A pointer to store the latency in. [out]

### gst_event_new_step ()

    GstEvent *          gst_event_new_step                  (GstFormat format,
                                                             guint64 amount,
                                                             gdouble rate,
                                                             gboolean flush,
                                                             gboolean intermediate);

Create a new step event. The purpose of the step event is to instruct a sink to skip `amount` (expressed in `format`) of media. It can be used to implement stepping through the video frame by frame or for doing fast trick modes.

A rate of <= 0.0 is not allowed. Pause the pipeline, for the effect of rate = 0.0 or first reverse the direction of playback using a seek event to get the same effect as rate < 0.0.

The `flush` flag will clear any pending data in the pipeline before starting the step operation.

The `intermediate` flag instructs the pipeline that this step operation is part of a larger step operation.

`format` : | the format of `amount`
`amount` : | the amount of data to step
`rate` : | the step rate
`flush` : | flushing steps
`intermediate` : | intermediate steps
Returns : | a new GstEvent. [transfer full]

### gst_event_parse_step ()

    void                gst_event_parse_step                (GstEvent *event,
                                                             GstFormat *format,
                                                             guint64 *amount,
                                                             gdouble *rate,
                                                             gboolean *flush,
                                                             gboolean *intermediate);

Parse the step event.

`event` : | The event to query
`format` : | a pointer to store the format in. [out][allow-none]
`amount` : | a pointer to store the amount in. [out][allow-none]
`rate` : | a pointer to store the rate in. [out][allow-none]
`flush` : | a pointer to store the flush boolean in. [out][allow-none]
`intermediate` : | a pointer to store the intermediate boolean in. [out][allow-none]

### gst_event_new_sink_message ()

    GstEvent *          gst_event_new_sink_message          (const gchar *name,
                                                             GstMessage *msg);

Create a new sink-message event. The purpose of the sink-message event is to instruct a sink to post the message contained in the event synchronized with the stream.

`name` is used to store multiple sticky events on one pad.

`name` : | a name for the event
`msg` : | the GstMessage to be posted. [transfer none]
Returns : | a new GstEvent. [transfer full]

### gst_event_parse_sink_message ()

    void                gst_event_parse_sink_message        (GstEvent *event,
                                                             GstMessage **msg);

Parse the sink-message event. Unref `msg` after usage.

`event` : | The event to query
`msg` : | a pointer to store the GstMessage in. [out][transfer full]

### gst_event_new_reconfigure ()

    GstEvent *          gst_event_new_reconfigure           (void);

Create a new reconfigure event. The purpose of the reconfingure event is to travel upstream and make elements renegotiate their caps or reconfigure their buffer pools. This is useful when changing properties on elements or changing the topology of the pipeline.

Returns : | a new GstEvent. [transfer full]

### gst_event_new_caps ()

    GstEvent *          gst_event_new_caps                  (GstCaps *caps);

Create a new CAPS event for `caps`. The caps event can only travel downstream synchronized with the buffer flow and contains the format of the buffers that will follow after the event.

`caps` : | a GstCaps. [transfer none]
Returns : | the new CAPS event. [transfer full]

### gst_event_parse_caps ()

    void                gst_event_parse_caps                (GstEvent *event,
                                                             GstCaps **caps);

Get the caps from `event`. The caps remains valid as long as `event` remains valid.

`event` : | The event to parse
`caps` : | A pointer to the caps. [out][transfer none]

### gst_event_new_toc ()

    GstEvent *          gst_event_new_toc                   (GstToc *toc,
                                                             gboolean updated);

Generate a TOC event from the given `toc`. The purpose of the TOC event is to inform elements that some kind of the TOC was found.

`toc` : | GstToc structure. [transfer none]
`updated` : | whether `toc` was updated or not.
Returns : | a new GstEvent. [transfer full]

### gst_event_parse_toc ()

    void                gst_event_parse_toc                 (GstEvent *event,
                                                             GstToc **toc,
                                                             gboolean *updated);

Parse a TOC `event` and store the results in the given `toc` and `updated` locations.

`event` : | a TOC event.
`toc` : | pointer to GstToc structure. [out][transfer full]
`updated` : | pointer to store TOC updated flag. [out]

### gst_event_new_toc_select ()

    GstEvent *          gst_event_new_toc_select            (const gchar *uid);

Generate a TOC select event with the given `uid`. The purpose of the TOC select event is to start playback based on the TOC's entry with the given `uid`.

`uid` : | UID in the TOC to start playback from.
Returns : | a new GstEvent.

### gst_event_parse_toc_select ()

    void                gst_event_parse_toc_select          (GstEvent *event,
                                                             gchar **uid);

Parse a TOC select `event` and store the results in the given `uid` location.

`event` : | a TOC select event.
`uid` : | storage for the selection UID. [out]

### gst_event_new_segment_done ()

    GstEvent *          gst_event_new_segment_done          (GstFormat format,
                                                             gint64 position);

Create a new segment-done event. This event is sent by elements that finish playback of a segment as a result of a segment seek.

`format` : | The format of the position being done
`position` : | The position of the segment being done
Returns : | a new GstEvent. [transfer full]

### gst_event_parse_segment_done ()

    void                gst_event_parse_segment_done        (GstEvent *event,
                                                             GstFormat *format,
                                                             gint64 *position);

Extracts the position and format from the segment done message.

`event` : | A valid GstEvent of type GST_EVENT_SEGMENT_DONE.
`format` : | Result location for the format, or NULL. [out][allow-none]
`position` : | Result location for the position, or NULL. [out][allow-none]

## See Also

GstPad, GstElement