Sets our main struct and passes it to the parent class
Abort the state change of the element. This function is used by elements that do asynchronous state changes and find out something is wrong. This function should be called with the STATE_LOCK held. MT safe.
This signals that the element will not generate more dynamic pads. Note that this signal will usually be emitted from the context of the streaming thread.
a new GstPad has been added to the element. Note that this signal will usually be emitted from the context of the streaming thread. Also keep in mind that if you add new elements to the pipeline in the signal handler you will need to set them to the desired target state with gst_element_set_state() or gst_element_sync_state_with_parent().
a GstPad has been removed from the element See Also GstElementFactory, GstPad
Adds a pad (link point) to element. pad's parent will be set to element; see gst_object_set_parent() for refcounting information. Pads are not automatically activated so elements should perform the needed steps to activate the pad in case this pad is added in the PAUSED or PLAYING state. See gst_pad_set_active() for more information about activating pads. The pad and the element should be unlocked when calling this function. This function will emit the "pad-added" signal on the element.
Set the caps property of an Element.
Perform transition on element. This function must be called with STATE_LOCK held and is mainly used internally.
Commit the state change of the element and proceed to the next pending state if any. This function is used by elements that do asynchronous state changes. The core will normally call this method automatically when an element returned GST_STATE_CHANGE_SUCCESS from the state change function. If after calling this method the element still has not reached the pending state, the next state change is performed. This method is used internally and should normally not be called by plugins or applications.
Creates a pad for each pad template that is always available. This function is only useful during object initialization of subclasses of GstElement.
Returns the base time of the element. The base time is the absolute time of the clock when this element was last put to PLAYING. Subtracting the base time from the clock time gives the running time of the element.
Returns the bus of the element. Note that only a GstPipeline will provide a bus for the application.
Gets the currently configured clock of the element. This is the clock as was last set with gst_element_set_clock().
Looks for an unlinked pad to which the given pad can link. It is not guaranteed that linking the pads will work, though it should work in most cases. This function will first attempt to find a compatible unlinked ALWAYS pad, and if none can be found, it will request a compatible REQUEST pad by looking at the templates of element.
Retrieves a pad template from element that is compatible with compattempl. Pads from compatible templates can be linked together.
Retrieves the factory that was used to create this element.
Retrieves a pad from the element by name (e.g. "src_%d"). This version only retrieves request pads. The pad should be released with gst_element_release_request_pad(). This method is slow and will be deprecated in the future. New code should use gst_element_request_pad() with the requested template.
Returns the start time of the element. The start time is the running time of the clock when this element was last put to PAUSED. Usually the start_time is managed by a toplevel element such as GstPipeline. MT safe.
Gets the state of the element. For elements that performed an ASYNC state change, as reported by gst_element_set_state(), this function will block up to the specified timeout value for the state change to complete. If the element completes the state change or goes into an error, this function returns immediately with a return value of GST_STATE_CHANGE_SUCCESS or GST_STATE_CHANGE_FAILURE respectively. For elements that did not return GST_STATE_CHANGE_ASYNC, this function returns the current and pending state immediately. This function returns GST_STATE_CHANGE_NO_PREROLL if the element successfully changed its state but is not able to provide data yet. This mostly happens for live sources that only produce data in GST_STATE_PLAYING. While the state change return is equivalent to GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that some sink elements might not be able to complete their state change because an element is not producing data to complete the preroll. When setting the element to playing, the preroll will complete and playback will start.
Retrieves a pad from element by name. This version only retrieves already-existing (i.e. 'static') pads.
the main Gtk struct as a void*
Checks if the state of an element is locked. If the state of an element is locked, state changes of the parent don't affect the element. This way you can leave currently unused elements inside bins. Just lock their state before changing the state from GST_STATE_NULL. MT safe.
Retrieves an iterator of element's pads. The iterator should be freed after usage. Also more specialized iterators exists such as gst_element_iterate_src_pads() or gst_element_iterate_sink_pads(). The order of pads returned by the iterator will be the order in which the pads were added to the element.
Retrieves an iterator of element's sink pads. The order of pads returned by the iterator will be the order in which the pads were added to the element.
Retrieves an iterator of element's source pads. The order of pads returned by the iterator will be the order in which the pads were added to the element.
Links src to dest. The link must be from source to destination; the other direction will not be tried. The function looks for existing pads that aren't linked yet. It will request new pads if necessary. Such pads need to be released manually when unlinking. If multiple links are possible, only one is established. Make sure you have added your elements to a bin or pipeline with gst_bin_add() before trying to link them.
Links src to dest using the given caps as filtercaps. The link must be from source to destination; the other direction will not be tried. The function looks for existing pads that aren't linked yet. It will request new pads if necessary. If multiple links are possible, only one is established. Make sure you have added your elements to a bin or pipeline with gst_bin_add() before trying to link them.
Links the two named pads of the source and destination elements. Side effect is that if one of the pads has no parent, it becomes a child of the parent of the other element. If they have different parents, the link fails.
Links the two named pads of the source and destination elements. Side effect is that if one of the pads has no parent, it becomes a child of the parent of the other element. If they have different parents, the link fails. If caps is not NULL, makes sure that the caps of the link is a subset of caps.
Links the two named pads of the source and destination elements. Side effect is that if one of the pads has no parent, it becomes a child of the parent of the other element. If they have different parents, the link fails. Calling gst_element_link_pads_full() with flags == GST_PAD_LINK_CHECK_DEFAULT is the same as calling gst_element_link_pads() and the recommended way of linking pads with safety checks applied. This is a convenience function for gst_pad_link_full().
This set's the filename for a filesrc element.
Brings the element to the lost state. The current state of the element is copied to the pending state so that any call to gst_element_get_state() will return GST_STATE_CHANGE_ASYNC. An ASYNC_START message is posted. If the element was PLAYING, it will go to PAUSED. The element will be restored to its PLAYING state by the parent pipeline when it prerolls again. This is mostly used for elements that lost their preroll buffer in the GST_STATE_PAUSED or GST_STATE_PLAYING state after a flush, they will go to their pending state again when a new preroll buffer is queued. This function can only be called when the element is currently not in error or an async state change. This function is used internally and should normally not be called from plugins or applications.
Post an error, warning or info message on the bus from inside an element. type must be of GST_MESSAGE_ERROR, GST_MESSAGE_WARNING or GST_MESSAGE_INFO. MT safe.
Use this function to signal that the element does not expect any more pads to show up in the current pipeline. This function should be called whenever pads have been added by the element itself. Elements with GST_PAD_SOMETIMES pad templates use this in combination with autopluggers to figure out that the element is done initializing its pads. This function emits the "no-more-pads" signal. MT safe.
Get's all the pads from an element in a Pad[].
Post a message on the element's GstBus. This function takes ownership of the message; if you want to access the message after this call, you should add an additional reference before calling.
Get the clock provided by the given element. Note An element is only required to provide a clock in the PAUSED state. Some elements can provide a clock in other states.
Performs a query on the given element. For elements that don't implement a query handler, this function forwards the query to a random srcpad or to the peer of a random linked sinkpad of this element. Please note that some queries might need a running pipeline to work.
Queries an element to convert src_val in src_format to dest_format.
Queries an element for the stream duration. This is a convenience function for gstreamerD.
Queries an element (usually top-level pipeline or playbin element) for the total stream duration in nanoseconds. This query will only work once the pipeline is prerolled (i.e. reached PAUSED or PLAYING state). The application will receive an ASYNC_DONE message on the pipeline bus when that is the case. If the duration changes for some reason, you will get a DURATION_CHANGED message on the pipeline bus, in which case you should re-query the duration using this function.
Queries an element for the stream position. This is a convenience function for gstreamerD.
Queries an element (usually top-level pipeline or playbin element) for the stream position in nanoseconds. This will be a value between 0 and the stream duration (if the stream duration is known). This query will usually only work once the pipeline is prerolled (i.e. reached PAUSED or PLAYING state). The application will receive an ASYNC_DONE message on the pipeline bus when that is the case. If one repeatedly calls this function one can also create a query and reuse it in gst_element_query().
Makes the element free the previously requested pad as obtained with gst_element_get_request_pad(). This does not unref the pad. If the pad was created by using gst_element_get_request_pad(), gst_element_release_request_pad() needs to be followed by gst_object_unref() to free the pad. MT safe.
Removes pad from element. pad will be destroyed if it has not been referenced elsewhere using gst_object_unparent(). This function is used by plugin developers and should not be used by applications. Pads that were dynamically requested from elements with gst_element_get_request_pad() should be released with the gst_element_release_request_pad() function instead. Pads are not automatically deactivated so elements should perform the needed steps to deactivate the pad in case this pad is removed in the PAUSED or PLAYING state. See gst_pad_set_active() for more information about deactivating pads. The pad and the element should be unlocked when calling this function. This function will emit the "pad-removed" signal on the element.
Retrieves a request pad from the element according to the provided template. Pad templates can be looked up using gst_element_factory_get_static_pad_templates(). The pad should be released with gst_element_release_request_pad().
For your convenience in gstreamerD: you can seek to the position of the pipeline measured in time_nanoseconds.
Sends a seek event to an element. See gst_event_new_seek() for the details of the parameters. The seek event is sent to the element using gst_element_send_event(). MT safe.
Simple API to perform a seek on the given element, meaning it just seeks to the given position relative to the start of the stream. For more complex operations like segment seeks (e.g. for looping) or changing the playback rate or seeking relative to the last configured playback segment you should use gst_element_seek(). In a completely prerolled PAUSED or PLAYING pipeline, seeking is always guaranteed to return TRUE on a seekable media type or FALSE when the media type is certainly not seekable (such as a live stream). Some elements allow for seeking in the READY state, in this case they will store the seek event and execute it when they are put to PAUSED. If the element supports seek in READY, it will always return TRUE when it receives the event in the READY state.
Sends an event to an element. If the element doesn't implement an event handler, the event will be pushed on a random linked sink pad for upstream events or a random linked source pad for downstream events. This function takes owership of the provided event so you should gst_event_ref() it if you want to reuse the event after this call. MT safe.
Set the base time of an element. See gst_element_get_base_time(). MT safe.
Sets the bus of the element. Increases the refcount on the bus. For internal use only, unless you're testing elements. MT safe.
Sets the clock for the element. This function increases the refcount on the clock. Any previously set clock on the object is unreffed.
Sets the context of the element. Increases the refcount of the context. MT safe.
Locks the state of an element, so state changes of the parent don't affect this element anymore. MT safe.
Set the start time of an element. The start time of the element is the running time of the element when it last went to the PAUSED state. In READY or after a flushing seek, it is set to 0. Toplevel elements like GstPipeline will manage the start_time and base_time on its children. Setting the start_time to GST_CLOCK_TIME_NONE on such a toplevel element will disable the distribution of the base_time to the children and can be useful if the application manages the base_time itself, for example if you want to synchronize capture from multiple pipelines, and you can also ensure that the pipelines have the same clock. MT safe.
Sets the state of the element. This function will try to set the requested state by going through all the intermediary states and calling the class's state change function for each. This function can return GST_STATE_CHANGE_ASYNC, in which case the element will perform the remainder of the state change asynchronously in another thread. An application can use gst_element_get_state() to wait for the completion of the state change or it can wait for a GST_MESSAGE_ASYNC_DONE or GST_MESSAGE_STATE_CHANGED on the bus. State changes to GST_STATE_READY or GST_STATE_NULL never return GST_STATE_CHANGE_ASYNC.
Tries to change the state of the element to the same as its parent. If this function returns FALSE, the state of element is undefined.
Unlinks all source pads of the source element with all sink pads of the sink element to which they are linked. If the link has been made using gst_element_link(), it could have created an requestpad, which has to be released using gst_element_release_request_pad().
Unlinks the two named pads of the source and destination elements. This is a convenience function for gst_pad_unlink().
Set key with value as metadata in klass.
Adds a padtemplate to an element class. This is mainly used in the _class_init functions of classes. If a pad template with the same name as an already existing one is added the old one is replaced by the new one.
Set key with value as metadata in klass. Same as gst_element_class_add_metadata(), but value must be a static string or an inlined string, as it will not be copied. (GStreamer plugins will be made resident once loaded, so this function can be used even from dynamically loaded plugins.)
Get metadata with key in klass.
Retrieves a padtemplate from element_class with the given name. Note If you use this function in the GInstanceInitFunc of an object class that has subclasses, make sure to pass the g_class parameter of the GInstanceInitFunc here.
Retrieves a list of the pad templates associated with element_class. The list must not be modified by the calling code. Note If you use this function in the GInstanceInitFunc of an object class that has subclasses, make sure to pass the g_class parameter of the GInstanceInitFunc here.
Sets the detailed information for a GstElementClass. Note This function is for use in _class_init functions only.
Sets the detailed information for a GstElementClass. Note This function is for use in _class_init functions only. Same as gst_element_class_set_metadata(), but longname, classification, description, and author must be static strings or inlined strings, as they will not be copied. (GStreamer plugins will be made resident once loaded, so this function can be used even from dynamically loaded plugins.)
Gets a string representing the given state change result.
Gets a string representing the given state.
the main Gtk struct
the main Gtk struct
the main Gtk struct as a void*
The deep notify signal is used to be notified of property changes. It is typically attached to the toplevel bin to receive notifications from all the elements contained in that bin.
Sets the name of object, or gives object a guaranteed unique name (if name is NULL). This function makes a copy of the provided name, so the caller retains ownership of the name it sent.
Returns a copy of the name of object. Caller should g_free() the return value after usage. For a nameless object, this returns NULL, which you can safely g_free() as well. Free-function: g_free
Sets the parent of object to parent. The object's reference count will be incremented, and any floating reference will be removed (see gst_object_ref_sink()).
Returns the parent of object. This function increases the refcount of the parent object so you should gst_object_unref() it after usage.
Clear the parent of object, removing the associated reference. This function decreases the refcount of object. MT safe. Grabs and releases object's lock.
A default deep_notify signal callback for an object. The user data should contain a pointer to an array of strings that should be excluded from the notify. The default handler will print the new value of the property using g_print. MT safe. This function grabs and releases object's LOCK for getting its path string.
A default error function that uses g_printerr() to display the error message and the optional debug sting.. The default handler will simply print the error string using g_print.
Checks to see if there is any object named name in list. This function does not do any locking of any kind. You might want to protect the provided list with the lock of the owner of the list. This function will lock each GstObject in the list to compare the name, so be carefull when passing a list with a locked object.
Check if object has an ancestor ancestor somewhere up in the hierarchy. One can e.g. check if a GstElement is inside a GstPipeline.
Increments the reference count on object. This function does not take the lock on object because it relies on atomic refcounting. This object returns the input parameter to ease writing
Decrements the reference count on object. If reference count hits zero, destroy object. This function does not take the lock on object as it relies on atomic refcounting. The unref method should never be called with the LOCK held since this might deadlock the dispose function.
Increase the reference count of object, and possibly remove the floating reference, if object has a floating reference. In other words, if the object is floating, then this call "assumes ownership" of the floating reference, converting it to a normal reference by clearing the floating flag while leaving the reference count unchanged. If the object is not floating, then this call adds a new normal reference increasing the reference count by one.
Atomically modifies a pointer to point to a new object. The reference count of oldobj is decreased and the reference count of newobj is increased. Either newobj and the value pointed to by oldobj may be NULL.
Generates a string describing the path of object in the object hierarchy. Only useful (or used) for debugging. Free-function: g_free
Returns a suggestion for timestamps where buffers should be split to get best controller results.
Sets the properties of the object, according to the GstControlSources that (maybe) handle them and for the given timestamp. If this function fails, it is most likely the application developers fault. Most probably the control sources are not setup correctly.
Check if the object has an active controlled properties.
This function is used to disable all controlled properties of the object for some time, i.e. gst_object_sync_values() will do nothing.
This function is used to disable the GstController on a property for some time, i.e. gst_controller_sync_values() will do nothing for the property.
Attach the GstControlBinding to the object. If there already was a GstControlBinding for this property it will be replaced. The object will take ownership of the binding.
Gets the corresponding GstControlBinding for the property. This should be unreferenced again after use.
Removes the corresponding GstControlBinding. If it was the last ref of the binding, it will be disposed.
Gets the value for the given controlled property at the requested time.
Gets a number of values for the given controlled property starting at the requested time. The array values need to hold enough space for n_values of the same type as the objects property's type. This function is useful if one wants to e.g. draw a graph of the control curve or apply a control curve sample by sample. The values are unboxed and ready to be used. The similar function gst_object_get_g_value_array() returns the array as GValues and is better suites for bindings.
Gets a number of GValues for the given controlled property starting at the requested time. The array values need to hold enough space for n_values of GValue. This function is useful if one wants to e.g. draw a graph of the control curve or apply a control curve sample by sample.
Obtain the control-rate for this object. Audio processing GstElement objects will use this rate to sub-divide their processing loop and call gst_object_sync_values() inbetween. The length of the processing segment should be up to control-rate nanoseconds. If the object is not under property control, this will return GST_CLOCK_TIME_NONE. This allows the element to avoid the sub-dividing. The control-rate is not expected to change if the element is in GST_STATE_PAUSED or GST_STATE_PLAYING.
Change the control-rate for this object. Audio processing GstElement objects will use this rate to sub-divide their processing loop and call gst_object_sync_values() inbetween. The length of the processing segment should be up to control-rate nanoseconds. The control-rate should not change if the element is in GST_STATE_PAUSED or GST_STATE_PLAYING.
GstElement is the abstract base class needed to construct an element that can be used in a GStreamer pipeline. Please refer to the plugin writers guide for more information on creating GstElement subclasses.
The name of a GstElement can be get with gst_element_get_name() and set with gst_element_set_name(). For speed, GST_ELEMENT_NAME() can be used in the core when using the appropriate locking. Do not use this in plug-ins or applications in order to retain ABI compatibility.
Elements can have pads (of the type GstPad). These pads link to pads on other elements. GstBuffer flow between these linked pads. A GstElement has a GList of GstPad structures for all their input (or sink) and output (or source) pads. Core and plug-in writers can add and remove pads with gst_element_add_pad() and gst_element_remove_pad().
An existing pad of an element can be retrieved by name with gst_element_get_static_pad(). A new dynamic pad can be created using gst_element_request_pad() with a GstPadTemplate or gst_element_get_request_pad() with the template name such as "src_%u". An iterator of all pads can be retrieved with gst_element_iterate_pads().
Elements can be linked through their pads. If the link is straightforward, use the gst_element_link() convenience function to link two elements, or gst_element_link_many() for more elements in a row. Use gst_element_link_filtered() to link two elements constrained by a specified set of GstCaps. For finer control, use gst_element_link_pads() and gst_element_link_pads_filtered() to specify the pads to link on each element by name.
Each element has a state (see GstState). You can get and set the state of an element with gst_element_get_state() and gst_element_set_state(). Setting a state triggers a GstStateChange. To get a string representation of a GstState, use gst_element_state_get_name().
You can get and set a GstClock on an element using gst_element_get_clock() and gst_element_set_clock(). Some elements can provide a clock for the pipeline if the GST_ELEMENT_FLAG_PROVIDE_CLOCK flag is set. With the gst_element_provide_clock() method one can retrieve the clock provided by such an element. Not all elements require a clock to operate correctly. If the #GST_ELEMENT_FLAG_REQUIRE_CLOCK() flag is set, a clock should be set on the element with gst_element_set_clock().
Note that clock slection and distribution is normally handled by the toplevel GstPipeline so the clock functions are only to be used in very specific situations.
Last reviewed on 2012-03-28 (0.11.3)