Pad

---

Object Hierarchy:

Description:

Content:

Properties:

• public Caps caps { owned get; }
• public PadDirection direction { construct set; get; }
• public PadTemplate template { set; owned get; }

Creation methods:

• public Pad (string name, PadDirection direction)
  Creates a new pad with the given name in the given direction. If name is NULL, a guaranteed unique name (across all pads) will be assigned. This function makes a copy of the name so you can safely free the name. MT safe.
• public Pad.from_static_template (StaticPadTemplate templ, string name)
  Creates a new pad with the given name from the given static template. If name is NULL, a guaranteed unique name (across all pads) will be assigned. This function makes a copy of the name so you can safely free the name.
• public Pad.from_template (PadTemplate templ, string name)
  Creates a new pad with the given name from the given template. If name is NULL, a guaranteed unique name (across all pads) will be assigned. This function makes a copy of the name so you can safely free the name.

Methods:

• public bool accept_caps (Caps caps)
  Check if the given pad accepts the caps.
• public bool activate_pull (bool active)
  Activates or deactivates the given pad in pull mode via dispatching to the pad's activatepullfunc. For use from within pad activation functions only. When called on sink pads, will first proxy the call to the peer pad, which is expected to activate its internally linked pads from within its activate_pull function. If you don't know what this is, you probably don't want to call it. MT safe.
• public bool activate_push (bool active)
  Activates or deactivates the given pad in push mode via dispatching to the pad's activatepushfunc. For use from within pad activation functions only. If you don't know what this is, you probably don't want to call it. MT safe.
• public uint add_buffer_probe (owned BufferProbeCallback handler)
  Adds a probe that will be called for all buffers passing through a pad. See gst_pad_add_data_probe for more information. The notify function is called when the probe is disconnected and usually used to free data.
• public uint add_data_probe (owned DataProbeCallback handler)
  Adds a "data probe" to a pad. This function will be called whenever data passes through a pad. In this case data means both events and buffers. The probe will be called with the data as an argument, meaning handler should have the same callback signature as the have_data signal. Note that the data will have a reference count greater than 1, so it will be immutable -- you must not change it. For source pads, the probe will be called after the blocking function, if any (see gst_pad_set_blocked_async), but before looking up the peer to chain to. For sink pads, the probe function will be called before configuring the sink with new caps, if any, and before calling the pad's chain function. Your data probe should return TRUE to let the data continue to flow, or FALSE to drop it. Dropping data is rarely useful, but occasionally comes in handy with events. Although probes are implemented internally by connecting handler to the have-data signal on the pad, if you want to remove a probe it is insufficient to only call g_signal_handler_disconnect on the returned handler id. To remove a probe, use the appropriate function, such as remove_data_probe. The notify function is called when the probe is disconnected and usually used to free data.
• public uint add_event_probe (owned EventProbeCallback handler)
  Adds a probe that will be called for all events passing through a pad. See gst_pad_add_data_probe for more information. The notify function is called when the probe is disconnected and usually used to free data.
• public FlowReturn alloc_buffer (uint64 offset, int size, Caps caps, out Buffer buf)
  Allocates a new, empty buffer optimized to push to pad pad. This function only works if pad is a source pad and has a peer. A new, empty Buffer will be put in the buf argument. You need to check the caps of the buffer after performing this function and renegotiate to the format if needed. If the caps changed, it is possible that the buffer returned in buf is not of the right size for the new format, buf needs to be unreffed and reallocated if this is the case. result code other than 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. MT safe.
• public FlowReturn alloc_buffer_and_set_caps (uint64 offset, int size, Caps caps, out Buffer buf)
  In addition to the function alloc_buffer, this function automatically calls set_caps when the caps of the newly allocated buffer are different from the pad caps. After a renegotiation, the size of the new buffer returned in buf could be of the wrong size for the new format and must be unreffed an reallocated in that case. result code other than 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. MT safe.
• public bool can_link (Pad sinkpad)
  Checks if the source pad and the sink pad are compatible so they can be linked.
• public FlowReturn chain (owned Buffer buffer)
  Chain a buffer to pad. The function returns WRONG_STATE if the pad was flushing. If the caps on buffer are different from the current caps on pad, this function will call any setcaps function (see set_setcaps_function) installed on pad. If the new caps are not acceptable for pad, this function returns NOT_NEGOTIATED. The function proceeds calling the chain function installed on pad (see set_chain_function) and the return value of that function is returned to the caller. NOT_SUPPORTED is returned if pad has no chain function. In all cases, success or failure, the caller loses its reference to buffer after calling this function. MT safe.
• public FlowReturn chain_list (owned BufferList list)
  Chain a bufferlist to pad. The function returns WRONG_STATE if the pad was flushing. If the caps on the first buffer of list are different from the current caps on pad, this function will call any setcaps function (see set_setcaps_function) installed on pad. If the new caps are not acceptable for pad, this function returns NOT_NEGOTIATED. The function proceeds calling the chainlist function installed on pad (see set_chain_list_function) and the return value of that function is returned to the caller. NOT_SUPPORTED is returned if pad has no chainlist function. In all cases, success or failure, the caller loses its reference to list after calling this function. MT safe.
• public bool check_pull_range ()
  Checks if a pull_range can be performed on the peer source pad. This function is used by plugins that want to check if they can use random access on the peer source pad. The peer sourcepad can implement a custom PadCheckGetRangeFunction if it needs to perform some logic to determine if pull_range is possible. MT safe.
• public bool dispatcher (PadDispatcherFunction dispatch)
  Invokes the given dispatcher function on each respective peer of all pads that are internally linked to the given pad. The GstPadDispatcherFunction should return TRUE when no further pads need to be processed.
• public bool event_default (owned Event event)
  Invokes the default event handler for the given pad. End-of-stream and discontinuity events are handled specially, and then the event is sent to all pads internally linked to pad. Note that if there are many possible sink pads that are internally linked to pad, only one will be sent an event. Multi-sinkpad elements should implement custom event handlers.
• public void fixate_caps (Caps caps)
  Fixate a caps on the given pad. Modifies the caps in place, so you should make sure that the caps are actually writable (see make_writable).
• public Caps get_allowed_caps ()
  Gets the capabilities of the allowed media types that can flow through The allowed capabilities is calculated as the intersection of the results of calling get_caps on pad and its peer. The caller owns a reference on the resulting caps. caps when you no longer need it. This function returns NULL when pad has no peer. MT safe.
• public Caps get_caps ()
  Gets the capabilities this pad can produce or consume. Note that this method doesn't necessarily return the caps set by set_caps - use GST_PAD_CAPS for that instead. gst_pad_get_caps returns all possible caps a pad can operate with, using the pad's get_caps function; this returns the pad template caps if not explicitly set. MT safe.
• public Caps get_caps_reffed ()
  Gets the capabilities this pad can produce or consume. Preferred function if one only wants to read or intersect the caps.
• public PadDirection get_direction ()
  Gets the direction of the pad. The direction of the pad is decided at construction time so this function does not take the LOCK. MT safe.
• public void* get_element_private ()
  Gets the private data of a pad. No locking is performed in this function.
• public Caps get_fixed_caps_func ()
  A helper function you can use as a GetCaps function that will return the currently negotiated caps or the padtemplate when NULL.
• public List<Pad> get_internal_links ()
  Gets a list of pads to which the given pad is linked to inside of the parent element. The caller must free this list after use. Not MT safe. of pads, free with g_list_free. could become invalid by the time the application accesses them. It's also possible that the list changes while handling the pads, which the caller of this function is unable to know. Use the thread-safe iterate_internal_links instead.
• public List<Pad> get_internal_links_default ()
  Gets a list of pads to which the given pad is linked to inside of the parent element. This is the default handler, and thus returns a list of all of the pads inside the parent element with opposite direction. The caller must free this list after use with g_list_free. of pads, or NULL if the pad has no parent. Not MT safe. could become invalid by the time the application accesses them. It's also possible that the list changes while handling the pads, which the caller of this function is unable to know. Use the thread-safe iterate_internal_links_default instead.
• public Caps get_negotiated_caps ()
  Gets the capabilities of the media type that currently flows through pad and its peer. This function can be used on both src and sinkpads. Note that srcpads are always negotiated before sinkpads so it is possible that the negotiated caps on the srcpad do not match the negotiated caps of the peer. the caps when you no longer need it. This function returns NULL when the pad has no peer or is not negotiated yet. MT safe.
• public weak PadTemplate get_pad_template ()
  Gets the template for pad. instantiated, or null if this pad has no template.
• public weak Caps get_pad_template_caps ()
  Gets the capabilities for pad's template. to keep a reference on the caps, make a copy (see copy).
• public Element? get_parent_element ()
  Gets the parent of pad, cast to a Element. If a pad has no parent or its parent is not an element, return NULL. reference on the parent, so unref when you're finished with it. MT safe.
• public Pad get_peer ()
  Gets the peer of pad. This function refs the peer pad so you need to unref it after use. MT safe.
• public weak QueryType[]? get_query_types ()
  Get an array of supported queries that can be performed on this pad. of QueryType.
• public weak QueryType[]? get_query_types_default ()
  Invoke the default dispatcher for the query types on the pad. of QueryType, or NULL if none of the internally-linked pads has a query types function.
• public FlowReturn get_range (uint64 offset, uint size, out Buffer buffer)
  When pad is flushing this function returns WRONG_STATE immediatly and buffer is null. Calls the getrange function of pad, see PadGetRangeFunction for a description of a getrange function. If pad has no getrange function installed (see set_getrange_function) this function returns NOT_SUPPORTED. This is a lowlevel function. Usualy pull_range is used. MT safe.
• public bool is_active ()
  Query if a pad is active MT safe.
• public bool is_blocked ()
  Checks if the pad is blocked or not. This function returns the last requested state of the pad. It is not certain that the pad is actually blocking at this point (see is_blocking). MT safe.
• public bool is_blocking ()
  Checks if the pad is blocking or not. This is a guaranteed state of whether the pad is actually blocking on a Buffer or a Event. MT safe.
• public bool is_linked ()
  Checks if a pad is linked to another pad or not. MT safe.
• public Iterator<Pad> iterate_internal_links ()
  Gets an iterator for the pads to which the given pad is linked to inside of the parent element. Each Pad element yielded by the iterator will have its refcount increased, so unref after use. pad does not have an iterator function configured. Use gst_iterator_free after usage.
• public Iterator<Pad> iterate_internal_links_default ()
  Iterate the list of pads to which the given pad is linked to inside of the parent element. This is the default handler, and thus returns an iterator of all of the pads inside the parent element with opposite direction. The caller must free this iterator after use with gst_iterator_free. returned pad with unref.
• public PadLinkReturn link (Pad sinkpad)
  Links the source pad and the sink pad. what went wrong. MT Safe.
• public PadLinkReturn link_full (Pad sinkpad, PadLinkCheck flags)
  Links the source pad and the sink pad. This variant of link provides a more granular control on the checks being done when linking. While providing some considerable speedups the caller of this method must be aware that wrong usage of those flags can cause severe issues. Refer to the documentation of PadLinkCheck for more information. MT Safe. what went wrong.
• public void load_and_link (Object parent)
  Reads the pad definition from the XML node and links the given pad in the element to a pad of an element up in the hierarchy.
• public bool pause_task ()
  Pause the task of pad. This function will also wait until the function executed by the task is finished if this function is not called from the task function. has no task.
• public bool peer_accept_caps (Caps caps)
  Check if the peer of pad accepts caps. If pad has no peer, this function returns TRUE.
• public Caps peer_get_caps ()
  Gets the capabilities of the peer connected to this pad. Similar to get_caps. peer pad. Use unref to get rid of it. This function returns null if there is no peer pad.
• public Caps peer_get_caps_reffed ()
  Gets the capabilities of the peer connected to this pad. Preferred function if one only wants to read or intersect the caps.
• public bool peer_query (Query query)
  Performs query on the peer of pad. The caller is responsible for both the allocation and deallocation of the query structure. if pad has no peer.
• public Caps proxy_getcaps ()
  Calls get_allowed_caps for every other pad belonging to the same element as pad, and returns the intersection of the results. This function is useful as a default getcaps function for an element that can handle any stream format, but requires all its pads to have the same caps. Two such elements are tee and adder.
• public bool proxy_setcaps (Caps caps)
  Calls set_caps for every other pad belonging to the same element as pad. If set_caps fails on any pad, the proxy setcaps fails. May be used only during negotiation.
• public FlowReturn pull_range (uint64 offset, uint size, out Buffer buffer)
  Pulls a buffer from the peer pad. This function will first trigger the pad block signal if it was installed. When pad is not linked NOT_LINKED is returned else this function returns the result of get_range on the peer pad. See get_range for a list of return values and for the semantics of the arguments of this function. configured on pad. Renegotiation within a running pull-mode pipeline is not supported. When this function returns OK, buffer will contain a valid Buffer that should be freed with unref after usage. OK is returned. MT safe.
• public FlowReturn push (owned Buffer buffer)
  Pushes a buffer to the peer of pad. This function will call an installed pad block before triggering any installed pad probes. If the caps on buffer are different from the currently configured caps on set_setcaps_function). In case of failure to renegotiate the new format, this function returns NOT_NEGOTIATED. The function proceeds calling chain on the peer pad and returns the value from that function. If pad has no peer, NOT_LINKED will be returned. In all cases, success or failure, the caller loses its reference to buffer after calling this function. MT safe.
• public bool push_event (owned Event event)
  Sends the event to the peer of the given pad. This function is mainly used by elements to send events to their peer elements. This function takes owership of the provided event so you should ref it if you want to reuse the event after this call. MT safe.
• public FlowReturn push_list (owned BufferList list)
  Pushes a buffer list to the peer of pad. This function will call an installed pad block before triggering any installed pad probes. If the caps on the first buffer in the first group of list are different from the currently configured caps on pad, this function will call any installed setcaps function on pad (see set_setcaps_function). In case of failure to renegotiate the new format, this function returns NOT_NEGOTIATED. If there are any probes installed on pad every group of the buffer list will be merged into a normal Buffer and pushed via gst_pad_push and the buffer list will be unreffed. The function proceeds calling the chain function on the peer pad and returns the value from that function. If pad has no peer, NOT_LINKED will be returned. If the peer pad does not have any installed chainlist function every group buffer of the list will be merged into a normal Buffer and chained via chain. In all cases, success or failure, the caller loses its reference to list after calling this function. MT safe.
• public bool query (Query query)
  Dispatches a query to a pad. The query should have been allocated by the caller via one of the type-specific allocation functions. The element that the pad belongs to is responsible for filling the query with an appropriate response, which should then be parsed with a type-specific query parsing function. Again, the caller is responsible for both the allocation and deallocation of the query structure. Please also note that some queries might need a running pipeline to work.
• public bool query_convert (Format src_format, int64 src_val, ref Format dest_format, out int64 dest_val)
  Queries a pad to convert src_val in src_format to dest_format.
• public bool query_default (Query query)
  Invokes the default query handler for the given pad. The query is sent to all pads internally linked to pad. Note that if there are many possible sink pads that are internally linked to Multi-sinkpad elements should implement custom query handlers.
• public bool query_duration (ref Format format, out int64 duration)
  Queries a pad for the total stream duration.
• public bool query_peer_convert (Format src_format, int64 src_val, ref Format dest_format, out int64 dest_val)
  Queries the peer pad of a given sink pad to convert src_val in src_format to dest_format.
• public bool query_peer_duration (ref Format format, out int64 duration)
  Queries the peer pad of a given sink pad for the total stream duration.
• public bool query_peer_position (ref Format format, out int64 cur)
  Queries the peer of a given sink pad for the stream position.
• public bool query_position (ref Format format, out int64 cur)
  Queries a pad for the stream position.
• public void remove_buffer_probe (uint handler_id)
  Removes a buffer probe from pad.
• public void remove_data_probe (uint handler_id)
  Removes a data probe from pad.
• public void remove_event_probe (uint handler_id)
  Removes an event probe from pad.
• public bool send_event (owned Event event)
  Sends the event to the pad. This function can be used by applications to send events in the pipeline. If pad is a source pad, event should be an upstream event. If pad is a sink pad, event should be a downstream event. For example, you would not send a EOS on a src pad; EOS events only propagate downstream. Furthermore, some downstream events have to be serialized with data flow, like EOS, while some can travel out-of-band, like FLUSH_START. If the event needs to be serialized with data flow, this function will take the pad's stream lock while calling its event function. To find out whether an event type is upstream, downstream, or downstream and serialized, see EventTypeFlags, get_flags, is_upstream, is_downstream, and is_serialized. Note that in practice that an application or plugin doesn't need to bother itself with this information; the core handles all necessary locks and checks. This function takes owership of the provided event so you should ref it if you want to reuse the event after this call.
• public void set_acceptcaps_function (PadAcceptCapsFunction acceptcaps)
  Sets the given acceptcaps function for the pad. The acceptcaps function will be called to check if the pad can accept the given caps. Setting the acceptcaps function to NULL restores the default behaviour of allowing any caps that matches the caps from get_caps.
• public void set_activate_function (PadActivateFunction activate)
  Sets the given activate function for pad. The activate function will dispatch to activate_push or activate_pull to perform the actual activation. Only makes sense to set on sink pads. Call this function if your sink pad can start a pull-based task.
• public void set_activatepull_function (PadActivateModeFunction activatepull)
  Sets the given activate_pull function for the pad. An activate_pull function prepares the element and any upstream connections for pulling. See XXX part-activation.txt for details.
• public void set_activatepush_function (PadActivateModeFunction activatepush)
  Sets the given activate_push function for the pad. An activate_push function prepares the element for pushing. See XXX part-activation.txt for details.
• public bool set_active (bool active)
  Activates or deactivates the given pad. Normally called from within core state change functions. If active, makes sure the pad is active. If it is already active, either in push or pull mode, just return. Otherwise dispatches to the pad's activate function to perform the actual activation. If not active, checks the pad's current mode and calls activate_push or activate_pull, as appropriate, with a FALSE argument. MT safe.
• public bool set_blocked (bool blocked)
  Blocks or unblocks the dataflow on a pad. This function is a shortcut for gst_pad_set_blocked_async with a NULL callback.
• public bool set_blocked_async (bool blocked, owned PadBlockCallback callback)
  Blocks or unblocks the dataflow on a pad. The provided callback is called when the operation succeeds; this happens right before the next attempt at pushing a buffer on the pad. This can take a while as the pad can only become blocked when real dataflow is happening. When the pipeline is stalled, for example in PAUSED, this can take an indeterminate amount of time. You can pass NULL as the callback to make this call block. Be careful with this blocking call as it might not return for reasons stated above.
• public void set_bufferalloc_function (PadBufferAllocFunction bufalloc)
  Sets the given bufferalloc function for the pad. Note that the bufferalloc function can only be set on sinkpads.
• public bool set_caps (Caps? caps)
  Sets the capabilities of this pad. The caps must be fixed. Any previous caps on the pad will be unreffed. This function refs the caps so you should unref if as soon as you don't need it anymore. It is possible to set NULL caps, which will make the pad unnegotiated again. or bad parameters were provided to this function. MT safe.
• public void set_chain_function (PadChainFunction chain)
  Sets the given chain function for the pad. The chain function is called to process a Buffer input buffer. see PadChainFunction for more details.
• public void set_chain_list_function (PadChainListFunction chainlist)
  Sets the given chain list function for the pad. The chainlist function is called to process a BufferList input buffer list. See PadChainListFunction for more details.
• public void set_checkgetrange_function (PadCheckGetRangeFunction check)
  Sets the given checkgetrange function for the pad. Implement this function on a pad if you dynamically support getrange based scheduling on the pad.
• public void set_element_private (void* priv)
  Set the given private data gpointer on the pad. This function can only be used by the element that owns the pad. No locking is performed in this function.
• public void set_event_function (PadEventFunction event)
  Sets the given event handler for the pad.
• public void set_fixatecaps_function (PadFixateCapsFunction fixatecaps)
  Sets the given fixatecaps function for the pad. The fixatecaps function will be called whenever the default values for a GstCaps needs to be filled in.
• public void set_getcaps_function (PadGetCapsFunction getcaps)
  Sets the given getcaps function for the pad. getcaps should return the allowable caps for a pad in the context of the element's state, its link to other elements, and the devices or files it has opened. These caps must be a subset of the pad template caps. In the NULL state with no links, getcaps should ideally return the same caps as the pad template. In rare circumstances, an object property can affect the caps returned by getcaps, but this is discouraged. You do not need to call this function if pad's allowed caps are always the same as the pad template caps. This can only be true if the padtemplate has fixed simple caps. For most filters, the caps returned by getcaps is directly affected by the allowed caps on other pads. For demuxers and decoders, the caps returned by the srcpad's getcaps function is directly related to the stream data. Again, helps with autoplugging. Note that the return value from getcaps is owned by the caller, so the caller should unref the caps after usage.
• public void set_getrange_function (PadGetRangeFunction get)
  Sets the given getrange function for the pad. The getrange function is called to produce a new Buffer to start the processing pipeline. see PadGetRangeFunction for a description of the getrange function.
• public void set_internal_link_function (PadIntLinkFunction intlink)
  Sets the given internal link function for the pad.
• public void set_iterate_internal_links_function (PadIterIntLinkFunction iterintlink)
  Sets the given internal link iterator function for the pad.
• public void set_link_function (PadLinkFunction link)
  Sets the given link function for the pad. It will be called when the pad is linked with another pad. The return value OK should be used when the connection can be made. The return value REFUSED should be used when the connection cannot be made for some reason. If link is installed on a source pad, it should call the PadLinkFunction of the peer sink pad, if present.
• public void set_query_function (PadQueryFunction query)
  Set the given query function for the pad.
• public void set_setcaps_function (PadSetCapsFunction setcaps)
  Sets the given setcaps function for the pad. The setcaps function will be called whenever a buffer with a new media type is pushed or pulled from the pad. The pad/element needs to update its internal structures to process the new media type. If this new type is not acceptable, the setcaps function should return FALSE.
• public void set_unlink_function (PadUnlinkFunction unlink)
  Sets the given unlink function for the pad. It will be called when the pad is unlinked.
• public bool start_task (TaskFunction func)
  Starts a task that repeatedly calls func with data. This function is mostly used in pad activation functions to start the dataflow. The stream_lock of pad will automatically be acquired before func is called.
• public bool stop_task ()
  Stop the task of pad. This function will also make sure that the function executed by the task will effectively stop if not called from the GstTaskFunction. This function will deadlock if called from the GstTaskFunction of the task. Use pause instead. Regardless of whether the pad has a task, the stream lock is acquired and released so as to ensure that streaming through this pad has finished.
• public void stream_lock ()
• public void stream_unlock ()
• public bool unlink (Pad sinkpad)
  Unlinks the source pad from the sink pad. Will emit the unlinked signal on both pads. the pads were not linked together. MT safe.
• public void use_fixed_caps ()
  A helper function you can use that sets the pad. This way the function will always return the negotiated caps or in case the pad is not negotiated, the padtemplate caps. Use this function on a pad that, once set_caps has been called on it, cannot be renegotiated to something else.

Signals:

• public virtual bool have_data (MiniObject data)
• public virtual void linked (Pad peer)
• public virtual void request_link ()
• public virtual void unlinked (Pad peer)

Fields:

• public weak PadAcceptCapsFunction acceptcapsfunc
• public weak PadActivateFunction activatefunc
• public weak PadActivateModeFunction activatepullfunc
• public weak PadActivateModeFunction activatepushfunc
• public weak PadBufferAllocFunction bufferallocfunc
• public weak PadChainFunction chainfunc
• public weak PadCheckGetRangeFunction checkgetrangefunc
• public void* element_private
• public weak PadEventFunction eventfunc
• public weak PadFixateCapsFunction fixatecapsfunc
• public weak PadGetCapsFunction getcapsfunc
• public weak PadGetRangeFunction getrangefunc
• public weak PadIntLinkFunction intlinkfunc
• public weak PadIterIntLinkFunction iterintlinkfunc
• public weak PadLinkFunction linkfunc
• public ActivateMode mode
• public weak PadQueryFunction queryfunc
• public weak PadQueryTypeFunction querytypefunc
• public weak PadSetCapsFunction setcapsfunc
• public weak PadUnlinkFunction unlinkfunc