GstEvent

Name

GstEvent -- Event definitions.

Synopsis


#include <gst/gst.h>


enum        GstEventType;
#define     GST_EVENT_TYPE                  (event)
#define     GST_EVENT_SRC                   (event)
#define     GST_EVENT_TIMESTAMP             (event)
enum        GstSeekType;
enum        GstSeekAccuracy;
#define     GST_EVENT_SEEK_TYPE             (event)
#define     GST_EVENT_SEEK_FORMAT           (event)
#define     GST_EVENT_SEEK_METHOD           (event)
#define     GST_EVENT_SEEK_FLAGS            (event)
#define     GST_EVENT_SEEK_OFFSET           (event)
#define     GST_EVENT_SEEK_ACCURACY         (event)
#define     GST_SEEK_FLAGS_MASK
#define     GST_SEEK_FLAGS_SHIFT
#define     GST_SEEK_FORMAT_MASK
#define     GST_SEEK_FORMAT_SHIFT
#define     GST_SEEK_METHOD_MASK
#define     GST_SEEK_METHOD_SHIFT
#define     GST_EVENT_DISCONT_NEW_MEDIA     (event)
#define     GST_EVENT_DISCONT_OFFSET        (event,i)
#define     GST_EVENT_DISCONT_OFFSET_LEN    (event)
#define     GST_EVENT_RATE_VALUE            (event)
#define     GST_EVENT_SEEK_ENDOFFSET        (event)
#define     GST_EVENT_SIZE_FORMAT           (event)
#define     GST_EVENT_SIZE_VALUE            (event)
struct      GstEvent;
GstEvent*   gst_event_new                   (GstEventType type);
#define     gst_event_copy                  (ev)
#define     gst_event_ref                   (ev)
#define     gst_event_ref_by_count          (ev,c)
#define     gst_event_unref                 (ev)
GstEvent*   gst_event_new_seek              (GstSeekType type,
                                             gint64 offset);
GstEvent*   gst_event_new_segment_seek      (GstSeekType type,
                                             gint64 start,
                                             gint64 stop);
GstEvent*   gst_event_new_size              (GstFormat format,
                                             gint64 value);
GstEvent*   gst_event_new_discontinuous     (gboolean new_media,
                                             GstFormat format1,
                                             ...);
gboolean    gst_event_discont_get_value     (GstEvent *event,
                                             GstFormat format,
                                             gint64 *value);
#define     gst_event_new_filler            ()
#define     gst_event_new_flush             ()
void        gst_event_print_stats           (void);

Description

The event classes are used to construct and query events.

Events are usually created with gst_event_new() which takes the event type as an argument. properties specific to the event can be set afterwards with the provided macros. The event should be unreferenced with gst_event_unref().

gst_event_new_seek() is a usually used to create a seek event and it takes the needed parameters for a seek event.

gst_event_new_flush() creates a new flush event.

Details

enum GstEventType

typedef enum {
  GST_EVENT_UNKNOWN,
  GST_EVENT_EOS,
  GST_EVENT_FLUSH,
  GST_EVENT_EMPTY,
  GST_EVENT_DISCONTINUOUS,
  GST_EVENT_NEW_MEDIA,
  GST_EVENT_QOS,
  GST_EVENT_SEEK,
  GST_EVENT_SEEK_SEGMENT,
  GST_EVENT_SEGMENT_DONE,
  GST_EVENT_SIZE,
  GST_EVENT_RATE,
  GST_EVENT_FILLER
} GstEventType;

The different major types of events.

GST_EVENT_UNKNOWNunknown event.
GST_EVENT_EOSan end-of-stream event.
GST_EVENT_FLUSHa flush event.
GST_EVENT_EMPTYan empty event.
GST_EVENT_DISCONTINUOUSa discontinuous event to indicate the stream has a discontinuity.
GST_EVENT_NEW_MEDIAa new media stream is started
GST_EVENT_QOSa quality of service event
GST_EVENT_SEEKa seek event.
GST_EVENT_SEEK_SEGMENTa segment seek with start and stop position
GST_EVENT_SEGMENT_DONEthe event that will be emited when the segment seek has ended
GST_EVENT_SIZEa size suggestion for a peer element
GST_EVENT_RATEadjust the output rate of an element
GST_EVENT_FILLERa dummy element that should be ignored by plugins


GST_EVENT_TYPE()

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

Get the event type.

event :The event to query.


GST_EVENT_SRC()

#define GST_EVENT_SRC(event)		(GST_EVENT(event)->src)

The source object that generated this event

event :The event to query


GST_EVENT_TIMESTAMP()

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

Get the timestamp of the event.

event :The event to query.


enum GstSeekType

typedef enum {
  /* | with some format */
  /* | with one of these */
  GST_SEEK_METHOD_CUR		= (1 << (GST_SEEK_METHOD_SHIFT + 0)),
  GST_SEEK_METHOD_SET		= (1 << (GST_SEEK_METHOD_SHIFT + 1)),
  GST_SEEK_METHOD_END		= (1 << (GST_SEEK_METHOD_SHIFT + 2)),

  /* | with optional seek flags */
  /* seek flags */
  GST_SEEK_FLAG_FLUSH		= (1 << (GST_SEEK_FLAGS_SHIFT + 0)),
  GST_SEEK_FLAG_ACCURATE	= (1 << (GST_SEEK_FLAGS_SHIFT + 1)),
  GST_SEEK_FLAG_KEY_UNIT	= (1 << (GST_SEEK_FLAGS_SHIFT + 2)),
  GST_SEEK_FLAG_SEGMENT_LOOP	= (1 << (GST_SEEK_FLAGS_SHIFT + 3))
	
} GstSeekType;

The different types of seek events.

GST_SEEK_METHOD_CURSeek to an relative position
GST_SEEK_METHOD_SETSeek to an absolute position
GST_SEEK_METHOD_ENDSeek relative to the end of the stream
GST_SEEK_FLAG_FLUSHFlush any pending data while seeking
GST_SEEK_FLAG_ACCURATESeek as accuratly as possible
GST_SEEK_FLAG_KEY_UNITSeek to a nearby key unit
GST_SEEK_FLAG_SEGMENT_LOOPLoop between start and stop in a segmented seek


enum GstSeekAccuracy

typedef enum {
  GST_SEEK_CERTAIN,
  GST_SEEK_FUZZY
} GstSeekAccuracy;

The seekaccuracy gives more information of how the seek was performed, if the seek was accurate or fuzzy.

GST_SEEK_CERTAINThe seek was exact
GST_SEEK_FUZZYThe seek was fuzzy, exact position can not be guaranteed


GST_EVENT_SEEK_TYPE()

#define GST_EVENT_SEEK_TYPE(event)		(GST_EVENT(event)->event_data.seek.type)

Get the seektype of the GST_EVENT_SEEK.

event :The event to query.


GST_EVENT_SEEK_FORMAT()

#define GST_EVENT_SEEK_FORMAT(event)		(GST_EVENT_SEEK_TYPE(event) & GST_SEEK_FORMAT_MASK)

The format of the seek value

event :The event operate on


GST_EVENT_SEEK_METHOD()

#define GST_EVENT_SEEK_METHOD(event)		(GST_EVENT_SEEK_TYPE(event) & GST_SEEK_METHOD_MASK)

The seek method to use as one of GstSeekType

event :The event operate on


GST_EVENT_SEEK_FLAGS()

#define GST_EVENT_SEEK_FLAGS(event)		(GST_EVENT_SEEK_TYPE(event) & GST_SEEK_FLAGS_MASK)

The optional seek flags

event :The event operate on


GST_EVENT_SEEK_OFFSET()

#define GST_EVENT_SEEK_OFFSET(event)		(GST_EVENT(event)->event_data.seek.offset)

Get the offset of the seek event.

event :The event to query.


GST_EVENT_SEEK_ACCURACY()

#define GST_EVENT_SEEK_ACCURACY(event)		(GST_EVENT(event)->event_data.seek.accuracy)

Indicates how accurate the event was performed.

event :The event to query


GST_SEEK_FLAGS_MASK

#define GST_SEEK_FLAGS_MASK	0xfff00000

Mask for the flags in the GstSeekType


GST_SEEK_FLAGS_SHIFT

#define GST_SEEK_FLAGS_SHIFT	20

Shift for the flags in the GstSeekType


GST_SEEK_FORMAT_MASK

#define GST_SEEK_FORMAT_MASK	0x0000ffff

Mask for the format in the GstSeekType


GST_SEEK_FORMAT_SHIFT

#define GST_SEEK_FORMAT_SHIFT	0

Shift for the format in the GstSeekType


GST_SEEK_METHOD_MASK

#define GST_SEEK_METHOD_MASK	0x000f0000

Mask for the method in the GstSeekType


GST_SEEK_METHOD_SHIFT

#define GST_SEEK_METHOD_SHIFT	16

Shift for the method in the GstSeekType


GST_EVENT_DISCONT_NEW_MEDIA()

#define GST_EVENT_DISCONT_NEW_MEDIA(event)	(GST_EVENT(event)->event_data.discont.new_media)

Flag that indicates the discont event was because of a new media type.

event :The event to operate on


GST_EVENT_DISCONT_OFFSET()

#define GST_EVENT_DISCONT_OFFSET(event,i)	(GST_EVENT(event)->event_data.discont.offsets[i])

The offset of the discont event. A discont evetn can hold up to 8 different format/value pairs.

event :The event to query
i :The offset/value pair.


GST_EVENT_DISCONT_OFFSET_LEN()

#define GST_EVENT_DISCONT_OFFSET_LEN(event)	(GST_EVENT(event)->event_data.discont.noffsets)

Get the number of offset/value pairs this event has.

event :The event to query.


GST_EVENT_RATE_VALUE()

#define GST_EVENT_RATE_VALUE(event)		(GST_EVENT(event)->event_data.rate.value)

Get access to the rate vale field

event :The event to query


GST_EVENT_SEEK_ENDOFFSET()

#define GST_EVENT_SEEK_ENDOFFSET(event)		(GST_EVENT(event)->event_data.seek.endoffset)

The event stop position for a segment seek

event :The event to query


GST_EVENT_SIZE_FORMAT()

#define GST_EVENT_SIZE_FORMAT(event)		(GST_EVENT(event)->event_data.size.format)

The format of the size event.

event :The event to query


GST_EVENT_SIZE_VALUE()

#define GST_EVENT_SIZE_VALUE(event)		(GST_EVENT(event)->event_data.size.value)

The value of the size event

event :The event to query


struct GstEvent

struct GstEvent {
  GstData data;

  GstEventType  type;
  guint64	timestamp;
  GstObject	*src;

  union {
    struct {
      GstSeekType 	type;
      gint64      	offset;
      gint64      	endoffset;
      GstSeekAccuracy 	accuracy;
    } seek;
    struct {
      GstFormatValue 	offsets[8];
      gint      	noffsets;
      gboolean		new_media;
    } discont;
    struct {
      GstFormat 	format;
      gint64      	value;
    } size;
    struct {
      gdouble      	value;
    } rate;
  } event_data;
};

The event data structure.

GstData dataThe parent data type.
GstEventType typeThe event type.
guint64 timestampThe event timestamp.
GstObject *srcThe object that generated the event


gst_event_new ()

GstEvent*   gst_event_new                   (GstEventType type);

Allocate a new event of the given type.

type : The type of the new event
Returns : A new event.


gst_event_copy()

#define         gst_event_copy(ev)         	GST_EVENT (gst_data_copy (GST_DATA (ev)))

Copy the event using the event specific copy function

ev :The event to copy
Returns :A new event that is a copy of the given input event


gst_event_ref()

#define         gst_event_ref(ev)             	gst_data_ref (GST_DATA (ev))

Increase the refcount of this event

ev :The event to refcount


gst_event_ref_by_count()

#define         gst_event_ref_by_count(ev,c)  	gst_data_ref_by_count (GST_DATA (ev), c)

Increase the refcount of the event with the given value

ev :The event to refcount
c :The value to add to the refcount


gst_event_unref()

#define         gst_event_unref(ev)           	gst_data_unref (GST_DATA (ev))

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

ev :The event to unref


gst_event_new_seek ()

GstEvent*   gst_event_new_seek              (GstSeekType type,
                                             gint64 offset);

Allocate a new seek event with the given parameters.

type : The type of the seek event
offset : The offset of the seek
Returns : A new seek event.


gst_event_new_segment_seek ()

GstEvent*   gst_event_new_segment_seek      (GstSeekType type,
                                             gint64 start,
                                             gint64 stop);

Allocate a new segment seek event with the given parameters.

type : The type of the seek event
start : The start offset of the seek
stop : The stop offset of the seek
Returns : A new segment seek event.


gst_event_new_size ()

GstEvent*   gst_event_new_size              (GstFormat format,
                                             gint64 value);

Create a new size event with the given values.

format : The format of the size value
value : The value of the size event
Returns : The new size event.


gst_event_new_discontinuous ()

GstEvent*   gst_event_new_discontinuous     (gboolean new_media,
                                             GstFormat format1,
                                             ...);

Allocate a new discontinuous event with the geven format/value pairs.

new_media : A flag indicating a new media type starts
format1 : The format of the discont value
... : more discont values and formats
Returns : A new discontinuous event.


gst_event_discont_get_value ()

gboolean    gst_event_discont_get_value     (GstEvent *event,
                                             GstFormat format,
                                             gint64 *value);

Get the value for the given format in the dicont event.

event : The event to query
format : The format of the discont value
value : A pointer to the value
Returns : TRUE if the discont event caries the specified format/value pair.


gst_event_new_filler()

#define		gst_event_new_filler()		gst_event_new(GST_EVENT_FILLER)

Create a new dummy event that should be ignored


gst_event_new_flush()

#define		gst_event_new_flush()		gst_event_new(GST_EVENT_FLUSH)

Create a new flush event.


gst_event_print_stats ()

void        gst_event_print_stats           (void);

Logs statistics about live events (using g_log).

See Also

GstPad