Top | ![]() |
![]() |
![]() |
![]() |
GObject ╰── GstObject ╰── GstPad ├── GstProxyPad │ ╰── GstGhostPad ╰── GstProxyPad ╰── GstGhostPad
GhostPads are useful when organizing pipelines with GstBin like elements. The idea here is to create hierarchical element graphs. The bin element contains a sub-graph. Now one would like to treat the bin-element like any other GstElement. This is where GhostPads come into play. A GhostPad acts as a proxy for another pad. Thus the bin can have sink and source ghost-pads that are associated with sink and source pads of the child elements.
If the target pad is known at creation time, gst_ghost_pad_new()
is the
function to use to get a ghost-pad. Otherwise one can use gst_ghost_pad_new_no_target()
to create the ghost-pad and use gst_ghost_pad_set_target()
to establish the
association later on.
Note that GhostPads add overhead to the data processing of a pipeline.
Last reviewed on 2005-11-18 (0.9.5)
GstPad * gst_ghost_pad_new (const gchar *name
,GstPad *target
);
Create a new ghostpad with target
as the target. The direction will be taken
from the target pad. target
must be unlinked.
Will ref the target.
GstPad * gst_ghost_pad_new_no_target (const gchar *name
,GstPadDirection dir
);
Create a new ghostpad without a target with the given direction.
A target can be set on the ghostpad later with the
gst_ghost_pad_set_target()
function.
The created ghostpad will not have a padtemplate.
GstPad * gst_ghost_pad_new_from_template (const gchar *name
,GstPad *target
,GstPadTemplate *templ
);
Create a new ghostpad with target
as the target. The direction will be taken
from the target pad. The template used on the ghostpad will be template
.
Will ref the target.
name |
the name of the new pad, or NULL to assign a default name. |
[allow-none] |
target |
the pad to ghost. |
[transfer none] |
templ |
the GstPadTemplate to use on the ghostpad. |
[transfer none] |
Since 0.10.10
GstPad * gst_ghost_pad_new_no_target_from_template (const gchar *name
,GstPadTemplate *templ
);
Create a new ghostpad based on templ
, without setting a target. The
direction will be taken from the templ
.
name |
the name of the new pad, or NULL to assign a default name. |
[allow-none] |
templ |
the GstPadTemplate to create the ghostpad from. |
[transfer none] |
Since 0.10.10
gboolean gst_ghost_pad_set_target (GstGhostPad *gpad
,GstPad *newtarget
);
Set the new target of the ghostpad gpad
. Any existing target
is unlinked and links to the new target are established. if newtarget
is
NULL the target will be cleared.
GstPad *
gst_ghost_pad_get_target (GstGhostPad *gpad
);
Get the target pad of gpad
. Unref target pad after usage.
the target GstPad, can be NULL if the ghostpad has no target set. Unref target pad after usage.
[transfer full]
gboolean
gst_ghost_pad_construct (GstGhostPad *gpad
);
Finish initialization of a newly allocated ghost pad.
This function is most useful in language bindings and when subclassing
GstGhostPad; plugin and application developers normally will not call this
function. Call this function directly after a call to g_object_new
(GST_TYPE_GHOST_PAD, "direction", dir
, ..., NULL).
Since 0.10.22
gboolean gst_ghost_pad_setcaps_default (GstPad *pad
,GstCaps *caps
);
Invoke the default setcaps function of a ghost pad.
Since 0.10.36
void
gst_ghost_pad_unlink_default (GstPad *pad
);
Invoke the default unlink function of a ghost pad.
Since 0.10.36
GstPadLinkReturn gst_ghost_pad_link_default (GstPad *pad
,GstPad *peer
);
Invoke the default link function of a ghost pad.
Since 0.10.36
gboolean gst_ghost_pad_activate_pull_default (GstPad *pad
,gboolean active
);
Invoke the default activate pull function of a ghost pad.
pad |
the GstPad to activate or deactivate. |
|
active |
whether the pad should be active or not. |
Since 0.10.36
gboolean gst_ghost_pad_activate_push_default (GstPad *pad
,gboolean active
);
Invoke the default activate push function of a ghost pad.
pad |
the GstPad to activate or deactivate. |
|
active |
whether the pad should be active or not. |
Since 0.10.36
gboolean gst_ghost_pad_internal_activate_push_default (GstPad *pad
,gboolean active
);
Invoke the default activate push function of a proxy pad that is owned by a ghost pad.
pad |
the GstPad to activate or deactivate. |
|
active |
whether the pad should be active or not. |
Since 0.10.36
gboolean gst_ghost_pad_internal_activate_pull_default (GstPad *pad
,gboolean active
);
Invoke the default activate pull function of a proxy pad that is owned by a ghost pad.
pad |
the GstPad to activate or deactivate. |
|
active |
whether the pad should be active or not. |
Since 0.10.36
GstProxyPad *
gst_proxy_pad_get_internal (GstProxyPad *pad
);
Get the internal pad of pad
. Unref target pad after usage.
The internal pad of a GstGhostPad is the internally used pad of opposite direction, which is used to link to the target.
Since 0.10.36
const GstQueryType *
gst_proxy_pad_query_type_default (GstPad *pad
);
Invoke the default query type handler of the proxy pad.
Since 0.10.36
gboolean gst_proxy_pad_event_default (GstPad *pad
,GstEvent *event
);
Invoke the default event of the proxy pad.
Since 0.10.36
gboolean gst_proxy_pad_query_default (GstPad *pad
,GstQuery *query
);
Invoke the default query function of the proxy pad.
Since 0.10.36
GstIterator *
gst_proxy_pad_iterate_internal_links_default
(GstPad *pad
);
GstFlowReturn gst_proxy_pad_bufferalloc_default (GstPad *pad
,guint64 offset
,guint size
,GstCaps *caps
,GstBuffer **buf
);
Invoke the default bufferalloc function of the proxy pad.
pad |
a source GstPad |
|
offset |
the offset of the new buffer in the stream |
|
size |
the size of the new buffer |
|
caps |
the caps of the new buffer |
|
buf |
a newly allocated buffer |
a result code indicating success of the operation. Any
result code other than GST_FLOW_OK is an error and buf
should
not be used.
An error can occur if the pad is not connected or when the downstream
peer elements cannot provide an acceptable buffer.
Since 0.10.36
GstFlowReturn gst_proxy_pad_chain_default (GstPad *pad
,GstBuffer *buffer
);
Invoke the default chain function of the proxy pad.
Since 0.10.36
GstFlowReturn gst_proxy_pad_chain_list_default (GstPad *pad
,GstBufferList *list
);
Invoke the default chain list function of the proxy pad.
pad |
a sink GstPad, returns GST_FLOW_ERROR if not. |
|
list |
the GstBufferList to send, return GST_FLOW_ERROR if not. |
[transfer full] |
Since 0.10.36
GstFlowReturn gst_proxy_pad_getrange_default (GstPad *pad
,guint64 offset
,guint size
,GstBuffer **buffer
);
gboolean
gst_proxy_pad_checkgetrange_default (GstPad *pad
);
Invoke the default checkgetrange function of the proxy pad.
Since 0.10.36
GstCaps *
gst_proxy_pad_getcaps_default (GstPad *pad
);
Invoke the default getcaps function of the proxy pad.
Since 0.10.36
gboolean gst_proxy_pad_acceptcaps_default (GstPad *pad
,GstCaps *caps
);
Invoke the default acceptcaps function of the proxy pad.
Since 0.10.36
void gst_proxy_pad_fixatecaps_default (GstPad *pad
,GstCaps *caps
);
Invoke the default fixatecaps function of the proxy pad.
Since 0.10.36
gboolean gst_proxy_pad_setcaps_default (GstPad *pad
,GstCaps *caps
);
Invoke the default setcaps function of the proxy pad.
TRUE if the caps could be set. FALSE if the caps were not fixed or bad parameters were provided to this function.
Since 0.10.36