gstreamer/docs/gst/tmpl/gstevent.sgml

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<!-- ##### SECTION Title ##### -->
GstEvent
<!-- ##### SECTION Short_Description ##### -->
Event definitions.
<!-- ##### SECTION Long_Description ##### -->
<para>
The event classes are used to construct and query events.
</para>
<para>
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().
</para>
<para>
gst_event_new_seek() is a usually used to create a seek event and it takes the
needed parameters for a seek event.
</para>
<para>
gst_event_new_flush() creates a new flush event.
</para>
<!-- ##### SECTION See_Also ##### -->
<para>
#GstPad, #GstElement
</para>
<!-- ##### ENUM GstEventType ##### -->
<para>
The different major types of events.
</para>
@GST_EVENT_UNKNOWN: unknown event.
@GST_EVENT_EOS: an end-of-stream event.
@GST_EVENT_FLUSH: a flush event.
@GST_EVENT_EMPTY: an empty event.
@GST_EVENT_DISCONTINUOUS: a discontinuous event to indicate the stream has a discontinuity.
@GST_EVENT_QOS: a quality of service event
@GST_EVENT_SEEK: a seek event.
@GST_EVENT_SEEK_SEGMENT: a segment seek with start and stop position
@GST_EVENT_SEGMENT_DONE: the event that will be emited when the segment seek has ended
@GST_EVENT_SIZE: a size suggestion for a peer element
@GST_EVENT_RATE: adjust the output rate of an element
@GST_EVENT_FILLER: a dummy event that should be ignored by plugins
@GST_EVENT_TS_OFFSET: an event to set the time offset on buffers
@GST_EVENT_INTERRUPT: mainly used by _get based elements when they were interrupted
while waiting for a buffer.
@GST_EVENT_NAVIGATION:
@GST_EVENT_TAG:
<!-- ##### MACRO GST_EVENT_TYPE ##### -->
<para>
Get the event type.
</para>
@event: The event to query.
<!-- ##### MACRO GST_EVENT_SRC ##### -->
<para>
The source object that generated this event
</para>
@event: The event to query
<!-- ##### MACRO GST_EVENT_TIMESTAMP ##### -->
<para>
Get the timestamp of the event.
</para>
@event: The event to query.
<!-- ##### ENUM GstEventFlag ##### -->
<para>
Event flags are used when querying for supported events
</para>
@GST_EVENT_FLAG_NONE: no value
@GST_RATE_FLAG_NEGATIVE: indicates negative rates are supported
<!-- ##### ENUM GstSeekType ##### -->
<para>
The different types of seek events. When constructing a seek event a format,
a seek method and optional flags are OR-ed together. The seek event is then
inserted into the graph with #gst_pad_send_event() or #gst_element_send_event().
<informalexample>
Following example illustrates how to insert a seek event (1 second in the stream)
in a pipeline.
<programlisting>
gboolean res;
GstEvent *event;
event = gst_event_new_seek (
GST_FORMAT_TIME | /* seek on time */
GST_SEEK_METHOD_SET | /* set the absolute position */
GST_SEEK_FLAG_FLUSH, /* flush any pending data */
1 * GST_SECOND); /* the seek offset (1 second) */
res = gst_element_send_event (GST_ELEMENT (osssink), event);
if (!res) {
g_warning ("seek failed");
}
</programlisting>
</informalexample>
</para>
@GST_SEEK_METHOD_CUR: Seek to an relative position
@GST_SEEK_METHOD_SET: Seek to an absolute position
@GST_SEEK_METHOD_END: Seek relative to the end of the stream
@GST_SEEK_FLAG_FLUSH: Flush any pending data while seeking
@GST_SEEK_FLAG_ACCURATE: Seek as accuratly as possible
@GST_SEEK_FLAG_KEY_UNIT: Seek to a nearby key unit
@GST_SEEK_FLAG_SEGMENT_LOOP: Loop between start and stop in a segmented seek
<!-- ##### ENUM GstSeekAccuracy ##### -->
<para>
The seekaccuracy gives more information of how the seek was performed,
if the seek was accurate or fuzzy.
</para>
@GST_SEEK_CERTAIN: The seek was exact
@GST_SEEK_FUZZY: The seek was fuzzy, exact position can not be guaranteed
<!-- ##### MACRO GST_EVENT_SEEK_TYPE ##### -->
<para>
Get the seektype of the GST_EVENT_SEEK.
</para>
@event: The event to query.
<!-- ##### MACRO GST_EVENT_SEEK_FORMAT ##### -->
<para>
The format of the seek value
</para>
@event: The event operate on
<!-- ##### MACRO GST_EVENT_SEEK_METHOD ##### -->
<para>
The seek method to use as one of #GstSeekType
</para>
@event: The event operate on
<!-- ##### MACRO GST_EVENT_SEEK_FLAGS ##### -->
<para>
The optional seek flags
</para>
@event: The event operate on
<!-- ##### MACRO GST_EVENT_SEEK_OFFSET ##### -->
<para>
Get the offset of the seek event.
</para>
@event: The event to query.
<!-- ##### MACRO GST_EVENT_SEEK_ACCURACY ##### -->
<para>
Indicates how accurate the event was performed.
</para>
@event: The event to query
<!-- ##### MACRO GST_SEEK_FLAGS_MASK ##### -->
<para>
Mask for the flags in the GstSeekType
</para>
<!-- ##### MACRO GST_SEEK_FLAGS_SHIFT ##### -->
<para>
Shift for the flags in the GstSeekType
</para>
<!-- ##### MACRO GST_SEEK_FORMAT_MASK ##### -->
<para>
Mask for the format in the GstSeekType
</para>
<!-- ##### MACRO GST_SEEK_FORMAT_SHIFT ##### -->
<para>
Shift for the format in the GstSeekType
</para>
<!-- ##### MACRO GST_SEEK_METHOD_MASK ##### -->
<para>
Mask for the method in the GstSeekType
</para>
<!-- ##### MACRO GST_SEEK_METHOD_SHIFT ##### -->
<para>
Shift for the method in the GstSeekType
</para>
<!-- ##### MACRO GST_EVENT_DISCONT_NEW_MEDIA ##### -->
<para>
Flag that indicates the discont event was because of a new media
type.
</para>
@event: The event to operate on
<!-- ##### MACRO GST_EVENT_DISCONT_OFFSET ##### -->
<para>
The offset of the discont event. A discont evetn can hold up to 8 different
format/value pairs.
</para>
@event: The event to query
@i: The offset/value pair.
<!-- ##### MACRO GST_EVENT_DISCONT_OFFSET_LEN ##### -->
<para>
Get the number of offset/value pairs this event has.
</para>
@event: The event to query.
<!-- ##### MACRO GST_EVENT_RATE_VALUE ##### -->
<para>
Get access to the rate vale field
</para>
@event: The event to query
<!-- ##### MACRO GST_EVENT_SEEK_ENDOFFSET ##### -->
<para>
The event stop position for a segment seek
</para>
@event: The event to query
<!-- ##### MACRO GST_EVENT_SIZE_FORMAT ##### -->
<para>
The format of the size event.
</para>
@event: The event to query
<!-- ##### MACRO GST_EVENT_SIZE_VALUE ##### -->
<para>
The value of the size event
</para>
@event: The event to query
<!-- ##### MACRO GST_EVENT_IS_INTERRUPT ##### -->
<para>
Check if the event is an interrupt event
</para>
@event: The event to check
<!-- ##### MACRO GST_EVENT_TRACE_NAME ##### -->
<para>
The name used for memory allocation tracing
</para>
<!-- ##### STRUCT GstEvent ##### -->
<para>
The event structure
</para>
@data:
@type:
@timestamp:
@src:
<!-- ##### FUNCTION gst_event_new ##### -->
<para>
</para>
@type:
@Returns:
<!-- ##### MACRO gst_event_copy ##### -->
<para>
Copy the event using the event specific copy function
</para>
@ev: The event to copy
@Returns: A new event that is a copy of the given input event
<!-- ##### MACRO gst_event_ref ##### -->
<para>
Increase the refcount of this event
</para>
@ev: The event to refcount
<!-- ##### MACRO gst_event_ref_by_count ##### -->
<para>
Increase the refcount of the event with the given value
</para>
@ev: The event to refcount
@c: The value to add to the refcount
<!-- ##### MACRO gst_event_unref ##### -->
<para>
Decrease the refcount of an event, freeing it if the refcount reaches 0
</para>
@ev: The event to unref
<!-- ##### FUNCTION gst_event_new_seek ##### -->
<para>
</para>
@type:
@offset:
@Returns:
<!-- ##### FUNCTION gst_event_new_segment_seek ##### -->
<para>
</para>
@type:
@start:
@stop:
@Returns:
<!-- ##### FUNCTION gst_event_new_size ##### -->
<para>
</para>
@format:
@value:
@Returns:
<!-- ##### FUNCTION gst_event_new_discontinuous ##### -->
<para>
</para>
@new_media:
@format1:
@Varargs:
@Returns:
<!-- ##### FUNCTION gst_event_discont_get_value ##### -->
<para>
</para>
@event:
@format:
@value:
@Returns:
<!-- ##### MACRO gst_event_new_filler ##### -->
<para>
Create a new dummy event that should be ignored
</para>
<!-- ##### MACRO gst_event_new_flush ##### -->
<para>
Create a new flush event.
</para>
<!-- ##### FUNCTION gst_event_masks_contains ##### -->
<para>
</para>
@masks:
@mask:
@Returns:
<!-- ##### MACRO GST_EVENT_MASK_FUNCTION ##### -->
<para>
A convenience macro to create event mask functions
</para>
@type: The type of the first argument of the function
@functionname: the name of the function
@...: event masks, the last element is marked with 0