Pad#

class Pad(**properties: Any)#

Superclasses: Object, InitiallyUnowned, Object

Subclasses: ProxyPad

A Element is linked to other elements via “pads”, which are extremely light-weight generic link points.

Pads have a PadDirection, source pads produce data, sink pads consume data.

Pads are typically created from a PadTemplate with new_from_template() and are then added to a Element. This usually happens when the element is created but it can also happen dynamically based on the data that the element is processing or based on the pads that the application requests.

Pads without pad templates can be created with new(), which takes a direction and a name as an argument. If the name is None, then a guaranteed unique name will be assigned to it.

A Element creating a pad will typically use the various gst_pad_set_*_function() calls to register callbacks for events, queries or dataflow on the pads.

pad_get_parent() will retrieve the Element that owns the pad.

After two pads are retrieved from an element by get_static_pad(), the pads can be linked with link(). (For quick links, you can also use link(), which will make the obvious link for you if it’s straightforward.). Pads can be unlinked again with unlink(). get_peer() can be used to check what the pad is linked to.

Before dataflow is possible on the pads, they need to be activated with set_active().

query() and peer_query() can be used to query various properties of the pad and the stream.

To send a Event on a pad, use send_event() and push_event(). Some events will be sticky on the pad, meaning that after they pass on the pad they can be queried later with get_sticky_event() and sticky_events_foreach(). get_current_caps() and has_current_caps() are convenience functions to query the current sticky CAPS event on a pad.

GstElements will use push() and pull_range() to push out or pull in a buffer.

The dataflow, events and queries that happen on a pad can be monitored with probes that can be installed with add_probe(). is_blocked() can be used to check if a block probe is installed on the pad. is_blocking() checks if the blocking probe is currently blocking the pad. remove_probe() is used to remove a previously installed probe and unblock blocking probes if any.

Pad have an offset that can be retrieved with get_offset(). This offset will be applied to the running_time of all data passing over the pad. set_offset() can be used to change the offset.

Convenience functions exist to start, pause and stop the task on a pad with start_task(), pause_task() and stop_task() respectively.

Constructors#

class Pad
classmethod new(name: str | None, direction: PadDirection) → Pad#

Creates a new pad with the given name in the given direction. If name is None, 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.

Parameters:

  • name – the name of the new pad.

  • direction – the PadDirection of the pad.

classmethod new_from_static_template(templ: StaticPadTemplate, name: str) → Pad#

Creates a new pad with the given name from the given static template. If name is None, 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.

Parameters:
classmethod new_from_template(templ: PadTemplate, name: str | None = None) → Pad#

Creates a new pad with the given name from the given template. If name is None, 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.

Parameters:

  • templ – the pad template to use

  • name – the name of the pad

Methods#

class Pad
activate_mode(mode: PadMode, active: bool) → bool#

Activates or deactivates the given pad in mode via dispatching to the pad’s activatemodefunc. For use from within pad activation functions only.

If you don’t know what this is, you probably don’t want to call it.

Parameters:

  • mode – the requested activation mode

  • active – whether or not the pad should be active.

add_probe(mask: PadProbeType, callback: Callable[[Pad, PadProbeInfo, Any], PadProbeReturn], user_data: Any = None) → int#

Be notified of different states of pads. The provided callback is called for every state that matches mask.

Probes are called in groups: First GST_PAD_PROBE_TYPE_BLOCK probes are called, then others, then finally GST_PAD_PROBE_TYPE_IDLE. The only exception here are GST_PAD_PROBE_TYPE_IDLE probes that are called immediately if the pad is already idle while calling add_probe(). In each of the groups, probes are called in the order in which they were added.

Parameters:

  • mask – the probe mask

  • callback – PadProbeCallback that will be called with notifications of the pad state

  • user_data – user data passed to the callback

Checks if the source pad and the sink pad are compatible so they can be linked.

Parameters:

sinkpad – the sink Pad.

chain(buffer: Buffer) → FlowReturn#

Chain a buffer to pad.

The function returns GST_FLOW_FLUSHING if the pad was flushing.

If the buffer type is not acceptable for pad (as negotiated with a preceding GST_EVENT_CAPS event), this function returns GST_FLOW_NOT_NEGOTIATED.

The function proceeds calling the chain function installed on pad (see pad_set_chain_function()) and the return value of that function is returned to the caller. GST_FLOW_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.

Parameters:

buffer – the Buffer to send, return GST_FLOW_ERROR if not.

chain_list(list: BufferList) → FlowReturn#

Chain a bufferlist to pad.

The function returns GST_FLOW_FLUSHING if the pad was flushing.

If pad was not negotiated properly with a CAPS event, this function returns GST_FLOW_NOT_NEGOTIATED.

The function proceeds calling the chainlist function installed on pad (see pad_set_chain_list_function()) and the return value of that function is returned to the caller. GST_FLOW_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.

Parameters:

list – the BufferList to send, return GST_FLOW_ERROR if not.

check_reconfigure() → bool#

Check and clear the GST_PAD_FLAG_NEED_RECONFIGURE flag on pad and return True if the flag was set.

create_stream_id(parent: Element, stream_id: str | None = None) → str#

Creates a stream-id for the source Pad pad by combining the upstream information with the optional stream_id of the stream of pad. pad must have a parent Element and which must have zero or one sinkpad. stream_id can only be None if the parent element of pad has only a single source pad.

This function generates an unique stream-id by getting the upstream stream-start event stream ID and appending stream_id to it. If the element has no sinkpad it will generate an upstream stream-id by doing an URI query on the element and in the worst case just uses a random number. Source elements that don’t implement the URI handler interface should ideally generate a unique, deterministic stream-id manually instead.

Since stream IDs are sorted alphabetically, any numbers in the stream ID should be printed with a fixed number of characters, preceded by 0’s, such as by using the format %03u instead of %u.

Parameters:

  • parent – Parent Element of pad

  • stream_id – The stream-id

do_linked(self, peer: Pad) → None#
Parameters:

peer

do_unlinked(self, peer: Pad) → None#
Parameters:

peer

event_default(parent: Object | None, event: Event) → bool#

Invokes the default event handler for the given pad.

The EOS event will pause the task associated with pad before it is forwarded to all internally linked pads,

The event is sent to all pads internally linked to pad. This function takes ownership of event.

Parameters:

  • parent – the parent of pad or None

  • event – the Event to handle.

forward(forward: Callable[[Pad, Any], bool], user_data: Any = None) → bool#

Calls forward for all internally linked pads of pad. This function deals with dynamically changing internal pads and will make sure that the forward function is only called once for each pad.

When forward returns True, no further pads will be processed.

Parameters:

  • forward – a PadForwardFunction

  • user_data – user data passed to forward

get_allowed_caps() → Caps | None#

Gets the capabilities of the allowed media types that can flow through pad and its peer.

The allowed capabilities is calculated as the intersection of the results of calling query_caps() on pad and its peer. The caller owns a reference on the resulting caps.

get_current_caps() → Caps | None#

Gets the capabilities currently configured on pad with the last GST_EVENT_CAPS event.

get_direction() → PadDirection#

Gets the direction of the pad. The direction of the pad is decided at construction time so this function does not take the LOCK.

get_element_private() → Any | None#

Gets the private data of a pad. No locking is performed in this function.

get_last_flow_return() → FlowReturn#

Gets the FlowReturn return from the last data passed by this pad.

Added in version 1.4.

get_offset() → int#

Get the offset applied to the running time of pad. pad has to be a source pad.

get_pad_template() → PadTemplate | None#

Gets the template for pad.

get_pad_template_caps() → Caps#

Gets the capabilities for pad's template.

get_parent_element() → Element | None#

Gets the parent of pad, cast to a Element. If a pad has no parent or its parent is not an element, return None.

get_peer() → Pad | None#

Gets the peer of pad. This function refs the peer pad so you need to unref it after use.

get_range(offset: int, size: int) → tuple[FlowReturn, Buffer]#

When pad is flushing this function returns GST_FLOW_FLUSHING immediately and buffer is None.

Calls the getrange function of pad, see PadGetRangeFunction for a description of a getrange function. If pad has no getrange function installed (see pad_set_getrange_function()) this function returns GST_FLOW_NOT_SUPPORTED.

If buffer points to a variable holding None, a valid new Buffer will be placed in buffer when this function returns GST_FLOW_OK. The new buffer must be freed with gst_buffer_unref() after usage.

When buffer points to a variable that points to a valid Buffer, the buffer will be filled with the result data when this function returns GST_FLOW_OK. If the provided buffer is larger than size, only size bytes will be filled in the result buffer and its size will be updated accordingly.

Note that less than size bytes can be returned in buffer when, for example, an EOS condition is near or when buffer is not large enough to hold size bytes. The caller should check the result buffer size to get the result size.

When this function returns any other result value than GST_FLOW_OK, buffer will be unchanged.

This is a lowlevel function. Usually pull_range() is used.

Parameters:

  • offset – The start offset of the buffer

  • size – The length of the buffer

If there is a single internal link of the given pad, this function will return it. Otherwise, it will return NULL.

Added in version 1.18.

get_sticky_event(event_type: EventType, idx: int) → Event | None#

Returns a new reference of the sticky event of type event_type from the event.

Parameters:

  • event_type – the EventType that should be retrieved.

  • idx – the index of the event

get_stream() → Stream | None#

Returns the current Stream for the pad, or None if none has been set yet, i.e. the pad has not received a stream-start event yet.

This is a convenience wrapper around get_sticky_event() and parse_stream().

Added in version 1.10.

get_stream_id() → str | None#

Returns the current stream-id for the pad, or None if none has been set yet, i.e. the pad has not received a stream-start event yet.

This is a convenience wrapper around get_sticky_event() and parse_stream_start().

The returned stream-id string should be treated as an opaque string, its contents should not be interpreted.

Added in version 1.2.

get_task_state() → TaskState#

Get pad task state. If no task is currently set, GST_TASK_STOPPED is returned.

Added in version 1.12.

has_current_caps() → bool#

Check if pad has caps set on it with a GST_EVENT_CAPS event.

is_active() → bool#

Query if a pad is active

is_blocked() → bool#

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()).

is_blocking() → bool#

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.

is_linked() → bool#

Checks if a pad is linked to another pad or not.

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.

Free-function: gst_iterator_free

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 free().

Parameters:

parent – the parent of pad or None

Links the source pad and the sink pad.

Parameters:

sinkpad – the sink Pad to link.

Links the source pad and the sink pad.

This variant of gst_pad_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.

Parameters:

  • sinkpad – the sink Pad to link.

  • flags – the checks to validate when linking

Gets a string representing the given pad-link return.

Added in version 1.4.

Links src to sink, creating any GhostPad's in between as necessary.

This is a convenience function to save having to create and add intermediate GhostPad's as required for linking across Bin boundaries.

If src or sink pads don’t have parent elements or do not share a common ancestor, the link will fail.

Added in version 1.10.

Parameters:

sink – a Pad

Links src to sink, creating any GhostPad's in between as necessary.

This is a convenience function to save having to create and add intermediate GhostPad's as required for linking across Bin boundaries.

If src or sink pads don’t have parent elements or do not share a common ancestor, the link will fail.

Calling link_maybe_ghosting_full() with flags == DEFAULT is the recommended way of linking pads with safety checks applied.

Added in version 1.10.

Parameters:
mark_reconfigure() → None#

Mark a pad for needing reconfiguration. The next call to check_reconfigure() will return True after this call.

needs_reconfigure() → bool#

Check the GST_PAD_FLAG_NEED_RECONFIGURE flag on pad and return True if the flag was set.

pause_task() → bool#

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.

peer_query(query: Query) → bool#

Performs query() on the peer of pad.

The caller is responsible for both the allocation and deallocation of the query structure.

Parameters:

query – the Query to perform.

peer_query_accept_caps(caps: Caps) → bool#

Check if the peer of pad accepts caps. If pad has no peer, this function returns True.

Parameters:

caps – a Caps to check on the pad

peer_query_caps(filter: Caps | None = None) → Caps#

Gets the capabilities of the peer connected to this pad. Similar to query_caps().

When called on srcpads filter contains the caps that upstream could produce in the order preferred by upstream. When called on sinkpads filter contains the caps accepted by downstream in the preferred order. filter might be None but if it is not None the returned caps will be a subset of filter.

Parameters:

filter – a Caps filter, or None.

peer_query_convert(src_format: Format, src_val: int, dest_format: Format) → tuple[bool, int]#

Queries the peer pad of a given sink pad to convert src_val in src_format to dest_format.

Parameters:

  • src_format – a Format to convert from.

  • src_val – a value to convert.

  • dest_format – the Format to convert to.

peer_query_duration(format: Format) → tuple[bool, int]#

Queries the peer pad of a given sink pad for the total stream duration.

Parameters:

format – the Format requested

peer_query_position(format: Format) → tuple[bool, int]#

Queries the peer of a given sink pad for the stream position.

Parameters:

format – the Format requested

proxy_query_accept_caps(query: Query) → bool#

Checks if all internally linked pads of pad accepts the caps in query and returns the intersection of the results.

This function is useful as a default accept caps query function for an element that can handle any stream format, but requires caps that are acceptable for all opposite pads.

Parameters:

query – an ACCEPT_CAPS Query.

proxy_query_caps(query: Query) → bool#

Calls query_caps() for all internally linked pads of pad and returns the intersection of the results.

This function is useful as a default caps query 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.

Parameters:

query – a CAPS Query.

pull_range(offset: int, size: int) → tuple[FlowReturn, Buffer]#

Pulls a buffer from the peer pad or fills up a provided buffer.

This function will first trigger the pad block signal if it was installed.

When pad is not linked GST_FLOW_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.

If buffer points to a variable holding None, a valid new Buffer will be placed in buffer when this function returns GST_FLOW_OK. The new buffer must be freed with gst_buffer_unref() after usage. When this function returns any other result value, buffer will still point to None.

When buffer points to a variable that points to a valid Buffer, the buffer will be filled with the result data when this function returns GST_FLOW_OK. When this function returns any other result value, buffer will be unchanged. If the provided buffer is larger than size, only size bytes will be filled in the result buffer and its size will be updated accordingly.

Note that less than size bytes can be returned in buffer when, for example, an EOS condition is near or when buffer is not large enough to hold size bytes. The caller should check the result buffer size to get the result size.

Parameters:

  • offset – The start offset of the buffer

  • size – The length of the buffer

push(buffer: Buffer) → FlowReturn#

Pushes a buffer to the peer of pad.

This function will call installed block probes before triggering any installed data probes.

The function proceeds calling chain() on the peer pad and returns the value from that function. If pad has no peer, GST_FLOW_NOT_LINKED will be returned.

In all cases, success or failure, the caller loses its reference to buffer after calling this function.

Parameters:

buffer – the Buffer to push returns GST_FLOW_ERROR if not.

push_event(event: Event) → bool#

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 ownership of the provided event so you should gst_event_ref() it if you want to reuse the event after this call.

Parameters:

event – the Event to send to the pad.

push_list(list: BufferList) → FlowReturn#

Pushes a buffer list to the peer of pad.

This function will call installed block probes before triggering any installed data probes.

The function proceeds calling the chain function on the peer pad and returns the value from that function. If pad has no peer, GST_FLOW_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.

Parameters:

list – the BufferList to push returns GST_FLOW_ERROR if not.

query(query: Query) → bool#

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.

Parameters:

query – the Query to perform.

query_accept_caps(caps: Caps) → bool#

Check if the given pad accepts the caps.

Parameters:

caps – a Caps to check on the pad

query_caps(filter: Caps | None = None) → Caps#

Gets the capabilities this pad can produce or consume. Note that this method doesn’t necessarily return the caps set by sending a new_caps() - use get_current_caps() for that instead. gst_pad_query_caps returns all possible caps a pad can operate with, using the pad’s CAPS query function, If the query fails, this function will return filter, if not None, otherwise ANY.

When called on sinkpads filter contains the caps that upstream could produce in the order preferred by upstream. When called on srcpads filter contains the caps accepted by downstream in the preferred order. filter might be None but if it is not None the returned caps will be a subset of filter.

Note that this function does not return writable Caps, use caps_make_writable() before modifying the caps.

Parameters:

filter – suggested Caps, or None

query_convert(src_format: Format, src_val: int, dest_format: Format) → tuple[bool, int]#

Queries a pad to convert src_val in src_format to dest_format.

Parameters:

  • src_format – a Format to convert from.

  • src_val – a value to convert.

  • dest_format – the Format to convert to.

query_default(parent: Object | None, query: Query) → bool#

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 pad, only one will be sent the query. Multi-sinkpad elements should implement custom query handlers.

Parameters:

  • parent – the parent of pad or None

  • query – the Query to handle.

query_duration(format: Format) → tuple[bool, int]#

Queries a pad for the total stream duration.

Parameters:

format – the Format requested

query_position(format: Format) → tuple[bool, int]#

Queries a pad for the stream position.

Parameters:

format – the Format requested

remove_probe(id: int) → None#

Remove the probe with id from pad.

MT safe.

Parameters:

id – the probe id to remove

send_event(event: Event) → bool#

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 GST_EVENT_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 GST_EVENT_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, gst_event_type_get_flags(), GST_EVENT_IS_UPSTREAM, GST_EVENT_IS_DOWNSTREAM, and GST_EVENT_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 ownership of the provided event so you should gst_event_ref() it if you want to reuse the event after this call.

Parameters:

event – the Event to send to the pad.

set_activate_function_full(activate: Callable[[Pad, Object], bool], user_data: Any = None) → None#

Sets the given activate function for pad. The activate function will dispatch to activate_mode() 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.

Parameters:

  • activate – the PadActivateFunction to set.

  • user_data – user_data passed to notify

set_activatemode_function_full(activatemode: Callable[[Pad, Object, PadMode, bool], bool], user_data: Any = None) → None#

Sets the given activate_mode function for the pad. An activate_mode function prepares the element for data passing.

Parameters:

  • activatemode – the PadActivateModeFunction to set.

  • user_data – user_data passed to notify

set_active(active: bool) → bool#

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, calls activate_mode() with the pad’s current mode and a False argument.

Parameters:

active – whether or not the pad should be active.

set_chain_function_full(chain: Callable[[Pad, Object | None, Buffer], FlowReturn], user_data: Any = None) → None#

Sets the given chain function for the pad. The chain function is called to process a Buffer input buffer. see PadChainFunction for more details.

Parameters:

  • chain – the PadChainFunction to set.

  • user_data – user_data passed to notify

set_chain_list_function_full(chainlist: Callable[[Pad, Object | None, BufferList], FlowReturn], user_data: Any = None) → None#

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.

Parameters:

  • chainlist – the PadChainListFunction to set.

  • user_data – user_data passed to notify

set_element_private(priv: Any = None) → None#

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.

Parameters:

priv – The private data to attach to the pad.

set_event_full_function_full(event: Callable[[Pad, Object | None, Event], FlowReturn], user_data: Any = None) → None#

Sets the given event handler for the pad.

Added in version 1.8.

Parameters:

  • event – the PadEventFullFunction to set.

  • user_data – user_data passed to notify

set_event_function_full(event: Callable[[Pad, Object | None, Event], bool], user_data: Any = None) → None#

Sets the given event handler for the pad.

Parameters:

  • event – the PadEventFunction to set.

  • user_data – user_data passed to notify

set_getrange_function_full(get: Callable[[Pad, Object | None, int, int, Buffer], FlowReturn], user_data: Any = None) → None#

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.

Parameters:

  • get – the PadGetRangeFunction to set.

  • user_data – user_data passed to notify

Sets the given internal link iterator function for the pad.

Parameters:

  • iterintlink – the PadIterIntLinkFunction to set.

  • user_data – user_data passed to notify

Sets the given link function for the pad. It will be called when the pad is linked with another pad.

The return value GST_PAD_LINK_OK should be used when the connection can be made.

The return value GST_PAD_LINK_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.

Parameters:

  • link – the PadLinkFunction to set.

  • user_data – user_data passed to notify

set_offset(offset: int) → None#

Set the offset that will be applied to the running time of pad.

Parameters:

offset – the offset

set_query_function_full(query: Callable[[Pad, Object | None, Query], bool], user_data: Any = None) → None#

Set the given query function for the pad.

Parameters:

  • query – the PadQueryFunction to set.

  • user_data – user_data passed to notify

Sets the given unlink function for the pad. It will be called when the pad is unlinked.

Note that the pad’s lock is already held when the unlink function is called, so most pad functions cannot be called from within the callback.

Parameters:

  • unlink – the PadUnlinkFunction to set.

  • user_data – user_data passed to notify

start_task(func: Callable[[Any], None], user_data: Any = None) → bool#

Starts a task that repeatedly calls func with user_data. This function is mostly used in pad activation functions to start the dataflow. The GST_PAD_STREAM_LOCK of pad will automatically be acquired before func is called.

Parameters:

  • func – the task function to call

  • user_data – user data passed to the task function

sticky_events_foreach(foreach_func: Callable[[Pad, Event | None, Any], bool], user_data: Any = None) → None#

Iterates all sticky events on pad and calls foreach_func for every event. If foreach_func returns False the iteration is immediately stopped.

Parameters:

  • foreach_func – the PadStickyEventsForeachFunction that should be called for every event.

  • user_data – the optional user data.

stop_task() → bool#

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.

store_sticky_event(event: Event) → FlowReturn#

Store the sticky event on pad

Added in version 1.2.

Parameters:

event – a Event

Unlinks the source pad from the sink pad. Will emit the Pad::unlinked signal on both pads.

Parameters:

sinkpad – the sink Pad to unlink.

use_fixed_caps() → None#

A helper function you can use that sets the FIXED_CAPS flag This way the default CAPS query will always return the negotiated caps or in case the pad is not negotiated, the padtemplate caps.

The negotiated caps are the caps of the last CAPS event that passed on the pad. Use this function on a pad that, once it negotiated to a CAPS, cannot be renegotiated to something else.

Properties#

class Pad
props.caps: Caps#

The type of the None singleton.

props.direction: PadDirection#
props.offset: int#

The offset that will be applied to the running time of the pad.

Added in version 1.6.

props.template: PadTemplate#

The type of the None singleton.

Signals#

class Pad.signals
linked(peer: Pad) → None#

The type of the None singleton.

Parameters:

peer – the peer pad that has been connected

unlinked(peer: Pad) → None#

The type of the None singleton.

Parameters:

peer – the peer pad that has been disconnected

Virtual Methods#

class Pad
do_linked(peer: Pad) → None#

The type of the None singleton.

Parameters:

peer

do_unlinked(peer: Pad) → None#

The type of the None singleton.

Parameters:

peer

Fields#

class Pad
activatedata#
activatefunc#
activatemodedata#
activatemodefunc#
activatemodenotify#
activatenotify#
block_cond#
chaindata#
chainfunc#
chainlistdata#
chainlistfunc#
chainlistnotify#
chainnotify#
direction#
The direction of the pad, cannot change after creating

the pad.

element_private#

Private data owned by the parent element

eventdata#
eventfunc#
eventnotify#
getrangedata#
getrangefunc#
getrangenotify#
iterintlinkdata#
iterintlinkfunc#
iterintlinknotify#
linkdata#
linkfunc#
linknotify#
mode#
num_blocked#
num_probes#
object#
offset#
padtemplate#

Padtemplate for this pad

peer#
priv#
probes#
querydata#
queryfunc#
querynotify#
stream_rec_lock#
task#
unlinkdata#
unlinkfunc#
unlinknotify#
On this page

This Page