GstPad
Object contained by elements that allows links to other elements
A #GstElement is linked to other elements via "pads", which are extremely
light-weight generic link points.
After two pads are retrieved from an element with gst_element_get_pad(),
the pads can be link with gst_pad_link(). (For quick links,
you can also use gst_element_link(), which will make the obvious
link for you if it's straightforward.)
Pads are typically created from a #GstPadTemplate with
gst_pad_new_from_template().
Pads have #GstCaps attached to it to describe the media type they
are capable of dealing with.
gst_pad_get_caps() and gst_pad_try_set_caps() are used to
manipulate the caps of the pads.
Pads created from a pad template cannot set capabilities that are
incompatible with the pad template capabilities.
Pads without pad templates can be created with gst_pad_new(),
which takes a direction and a name as an argument. If the name is NULL,
then a guaranteed unique name will be assigned to it.
gst_pad_get_parent() will retrieve the #GstElement that owns the pad.
A #GstElement creating a pad will typically use the various
gst_pad_set_*_function() calls to register callbacks for various events
on the pads.
GstElements will use gst_pad_push() and gst_pad_pull() to push out
or pull in a buffer.
gst_pad_select() and gst_pad_selectv() are used by plugins to wait for the
first incoming buffer or event on any of the given set of pads.
To send a #GstEvent on a pad, use gst_pad_send_event().
Last reviewed on December 13th, 2002 (0.5.0.1)
#GstPadTemplate, #GstElement, #GstEvent
Macro to test if the given #GstPadLinkReturn value indicates a
failed negotiation step (REFUSED/DELAYED).
@ret: the #GstPadLinkReturn value
Macro to test if the given #GstPadLinkReturn value indicates a
successfull negotiation step (OK/DONE).
@ret: the #GstPadLinkReturn value
A convenience macro to construct query type functions
@functionname: the name of the function
@...: query types, 0 to mark the last element
Convenience function to define an array of formats that can be used
as #GstPadGetFormatsFunction.
@functionname: The name of the function
@...: comma separated list of formats, 0 to mark the end
Convenience function to define an array of event masks that can be used
as #GstPadGetEventMaskFunction.
@functionname: The name of the function
@...: comma separated list of event maks, { 0, } to mark the end
A function that will be called when chaining buffers.
@pad: the #GstPad that performed the chain.
@buffer:
@Returns:
@data:
@buf: the #GstBuffer that is chained.
Function signature to handle an event for the pad.
@pad: the #GstPad to handle the event.
@event: the #GstEvent to handle.
@Returns: TRUE if the pad could handle the event.
The signature of a convert function.
@pad: the #GstPad to perform the convert on.
@src_format: the source #GstFormat of the conversion.
@src_value: the source value of the conversion.
@dest_format: a pointer to the destination #GstFormat.
@dest_value: a pointer to the destination value.
@Returns: TRUE if the conversion could be performed.
The signature of the query function.
@pad: the #GstPad to query.
@type: the #GstPadQueryType.
@format: a pointer to the target #GstFormat.
@value: a pointer to the target value.
@Returns: TRUE if the query could be performed.
The signature of the internal pad link function.
@pad: The #GstPad to query.
@Returns: a newly allocated #GList of pads that are linked to
the given pad on the inside of the parent element.
The caller must call g_list_free() on it after use.
The signature of the formats function.
@pad: a #GstPad to query
@Returns: an array of formats
The signature of the eventmask function.
@pad: the #GstPad to query
@Returns: an array of event masks
The signature of the query types function.
@pad: a #GstPad to query
@Returns: an array of query types
Function signature to handle a new link on the pad.
@pad: the #GstPad that is linked.
@peer:
@Returns: the result of the link with the specified caps.
@caps: the peer's #GstCaps.
@pad:
Returns a copy of the capabilities of the specified pad. By default this
function will return the pad template capabilities, but can optionally
be overridden.
@pad: the #GstPad to get the capabilities of.
@Returns: a newly allocated copy #GstCaps of the pad.
@caps: the peer's #GstCaps, can be used to filter the capabilities.
@pad:
@offset:
@size:
@caps:
@Returns:
A dispatcher function is called for all internally linked pads, see
gst_pad_dispatcher().
@pad: the #GstPad that is dispatched.
@data: the gpointer to optional user data.
@Returns: TRUE if the dispatching procedure has to be stopped.
The direction of a pad.
@GST_PAD_UNKNOWN: direction is unknown.
@GST_PAD_SRC: the pad is a source pad.
@GST_PAD_SINK: the pad is a sink pad.
@GST_PAD_ACTIVE:
@GST_PAD_BLOCKED:
@GST_PAD_FLUSHING:
@GST_PAD_IN_GETCAPS:
@GST_PAD_IN_SETCAPS:
@GST_PAD_FLAG_LAST:
The result of a pad link.
@GST_PAD_LINK_NOSCHED:
@GST_PAD_LINK_NOFORMAT:
@GST_PAD_LINK_REFUSED: the link was refused.
@GST_PAD_LINK_WRONG_DIRECTION:
@GST_PAD_LINK_WAS_LINKED:
@GST_PAD_LINK_OK: the link succeeded.
Indicates when this pad will become available.
@GST_PAD_ALWAYS: the pad is always available
@GST_PAD_SOMETIMES: the pad will become available depending on the media stream
@GST_PAD_REQUEST: the pad is only available on request with
gst_element_request_pad_by_name() or gst_element_request_compatible_pad().
Gets the name of the pad.
@pad: a #GstPad to get the name of.
@Returns: the pad's name.
Gets the parent element of this pad.
@pad: a #GstPad to get the parent of.
@Returns: the parent #GstElement of this pad.
Gets the private data set by the element that owns the pad.
@pad: a #GstPad to get the private data of.
#Returns: a gpointer to the private data.
Gets the pad template that was used to create this pad.
@pad: a #GstPad to get the pad template of.
#Returns: the #GstPadTemplate used to create the pad, or NULL if none was
used.
Returns the real pad of this pad.
@pad: a #GstPad to realize.
@Returns: the actual #GstPad.
Gets the pad's direction.
@pad: a #GstPad to get the direction of.
@Returns: the #GstPadDirection of the pad.
Gets the capabilities of a pad.
@pad: a #GstPad to get the capabilities of.
@Returns: the #GstCaps of the pad.
Gets the peer pad of this pad. The peer pad is the pad on to which the parent
element is linked through this pad.
@pad: a #GstPad to get the peer pad of.
@Returns: the peer #GstPad.
Checks if the pad is linked.
@pad: a #GstPad to check.
Checks if the pad is active.
@pad: a #GstPad to check
@pad:
Checks if a pad is usable. A usable pad is both linked and active.
@pad: a #GstPad to check
Checks if buffers can be pulled from this buffer.
@pad: a #GstPad to check on if a buffer can be pulled from it.
Checks if the pad is a source pad.
@pad: a #GstPad to check.
Checks if the pad is a sink pad.
@pad: a #GstPad to check.
@name:
@direction:
@Returns:
@templ:
@name:
@Returns:
@type:
@name:
@direction:
@Returns:
@type:
@templ:
@name:
@Returns:
@pad:
@name:
@pad:
@Returns:
@pad:
@Returns:
@pad:
@mode:
@Returns:
@active:
@pad:
@Returns:
@pad:
@priv:
@pad:
@Returns:
@pad:
@parent:
@pad:
@Returns:
@pad:
@Returns:
@pad:
@Returns:
@pad:
@bufalloc:
@bufferalloc:
@pad:
@offset:
@size:
@caps:
@Returns:
@pad:
@chain:
@pad:
@event:
@pad:
@mask_func:
@pad:
@Returns:
@pad:
@Returns:
@pad:
@link:
@srcpad:
@sinkpad:
@Returns:
@srcpad:
@sinkpad:
@filtercaps:
@Returns:
@pad:
@unlink:
@srcpad:
@sinkpad:
@Returns:
@srcpad:
@sinkpad:
@filtercaps:
@Returns:
@srcpad:
@sinkpad:
@Returns:
@pad:
@Returns:
@pad:
@Returns:
@pad:
@Returns:
@pad:
@Returns:
@pad:
@Returns:
@pad:
@getcaps:
@pad:
@Returns:
@srcpad:
@sinkpad:
@filtercaps:
@Returns:
@srcpad:
@Returns:
@pad:
@pad:
@buffer:
@Returns:
@data:
@buf:
@pad:
@event:
@Returns:
@pad:
@event:
@Returns:
@pad:
@formats:
@pad:
@Returns:
@pad:
@Returns:
@pad:
@convert:
@pad:
@src_format:
@src_value:
@dest_format:
@dest_value:
@Returns:
@pad:
@src_format:
@src_value:
@dest_format:
@dest_value:
@Returns:
@pad:
@query:
@pad:
@type_func:
@pad:
@Returns:
@pad:
@Returns:
@pad:
@type:
@format:
@value:
@Returns:
@pad:
@type:
@format:
@value:
@Returns:
@pad:
@intlink:
@pad:
@Returns:
@pad:
@Returns:
@pad:
@dispatch:
@data:
@Returns:
Adds the probe to the given pad
@pad: The pad to add the probe to
@probe: The probe to add to the pad
Remove the probe from the pad
@pad: The pad to remove the probe of
@probe: The probe to remove
@self:
@parent: