gstreamermm  1.4.3
Public Types | Public Member Functions | Static Public Member Functions | Protected Member Functions | Related Functions | List of all members
Gst::Pad Class Reference

A class that represents objects contained by elements that allows links to other elements. More...

Inheritance diagram for Gst::Pad:
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Collaboration diagram for Gst::Pad:
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Public Types

typedef sigc::slot
< PadProbeReturn, const
Glib::RefPtr< Gst::Pad >
&, const Gst::PadProbeInfo& > 
SlotProbe
 For example, bool on_have_data(const Glib::RefPtr<Gst::Pad>& pad, const Glib::RefPtr<Gst::MiniObjec>& data);. More...
 
typedef sigc::slot
< Gst::FlowReturn, const
Glib::RefPtr< Gst::Pad >
&, Glib::RefPtr< Gst::Buffer >& > 
SlotChain
 
typedef sigc::slot< gboolean,
const Glib::RefPtr< Gst::Pad >
&, Glib::RefPtr< Gst::Event >& > 
SlotEvent
 
typedef sigc::slot< gboolean,
const Glib::RefPtr< Gst::Pad >
&, const Glib::RefPtr
< Gst::Query >& > 
SlotQuery
 
typedef sigc::slot< bool,
const Glib::RefPtr< Gst::Pad >& > 
SlotActivate
 
typedef sigc::slot< bool,
const Glib::RefPtr< Gst::Pad >
&, Gst::PadMode, bool > 
SlotActivatemode
 
typedef sigc::slot
< Gst::FlowReturn, const
Glib::RefPtr< Gst::Pad >
&, guint64, guint,
Glib::RefPtr< Gst::Buffer >& > 
SlotGetrange
 

Public Member Functions

virtual ~Pad ()
 
GstPad* gobj ()
 Provides access to the underlying C GObject. More...
 
const GstPad* gobj () const
 Provides access to the underlying C GObject. More...
 
GstPad* gobj_copy ()
 Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs. More...
 
Glib::RefPtr< Gst::Capsquery_caps (Glib::RefPtr< Gst::Caps > caps)
 Gets the capabilities this pad can produce or consume. More...
 
Glib::RefPtr< const Gst::Capsquery_caps (Glib::RefPtr< Gst::Caps > caps) const
 Gets the capabilities this pad can produce or consume. More...
 
PadDirection get_direction () const
 Gets the direction of the pad. More...
 
Glib::RefPtr< Gst::Elementget_parent_element ()
 Gets the parent of pad, cast to a Gst::Element. More...
 
Glib::RefPtr< const Gst::Elementget_parent_element () const
 Gets the parent of pad, cast to a Gst::Element. More...
 
Glib::RefPtr< Gst::PadTemplateget_pad_template ()
 Gets the template for pad. More...
 
Glib::RefPtr< const
Gst::PadTemplate
get_pad_template () const
 Gets the template for pad. More...
 
PadLinkReturn link (const Glib::RefPtr< Gst::Pad >& sink_pad)
 Links the source pad and the sink pad. More...
 
bool unlink (const Glib::RefPtr< Gst::Pad >& sink_pad)
 Unlinks the source pad from the sink pad. More...
 
bool is_linked () const
 Checks if a pad is linked to another pad or not. More...
 
bool can_link (const Glib::RefPtr< const Gst::Pad >& other_pad) const
 Checks if the source pad and the sink pad are compatible so they can be linked. More...
 
Glib::RefPtr< Gst::Capsget_allowed_caps ()
 Gets the capabilities of the allowed media types that can flow through pad and its peer. More...
 
Glib::RefPtr< const Gst::Capsget_allowed_caps () const
 Gets the capabilities of the allowed media types that can flow through pad and its peer. More...
 
Glib::RefPtr< const Gst::Capsget_pad_template_caps () const
 Gets the capabilities for pad's template. More...
 
gulong add_probe (PadProbeType mask, const SlotProbe& slot)
 
void remove_probe (gulong id)
 Remove the probe with id from pad. More...
 
Glib::RefPtr< Gst::Padget_peer ()
 Gets the peer of pad. More...
 
Glib::RefPtr< const Gst::Padget_peer () const
 Gets the peer of pad. More...
 
void use_fixed_caps ()
 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. More...
 
bool is_active () const
 Query if a pad is active. More...
 
bool is_blocked () const
 Checks if the pad is blocked or not. More...
 
bool is_blocking () const
 Checks if the pad is blocking or not. More...
 
FlowReturn get_range (guint64 offset, guint size, Glib::RefPtr< Gst::Buffer >& buffer)
 When pad is flushing this function returns Gst::FLOW_WRONG_STATE immediatly. More...
 
bool query_accept_caps (const Glib::RefPtr< const Gst::Caps >& caps) const
 Check if the given pad accepts the caps. More...
 
bool proxy_query_caps (const Glib::RefPtr< Gst::Query >&query)
 Calls query_caps() for all internally linked pads fof pad and returns the intersection of the results. More...
 
bool proxy_query_caps (const Glib::RefPtr< Gst::Query >&query) const
 Calls query_caps() for all internally linked pads fof pad and returns the intersection of the results. More...
 
bool peer_query_accept_caps (const Glib::RefPtr< const Gst::Caps >& caps) const
 Check if the peer of pad accepts caps. More...
 
FlowReturn push (Glib::RefPtr< Gst::Buffer >& buffer)
 Pushes a buffer to the peer of the pad. More...
 
bool push_event (const Glib::RefPtr< Gst::Event >& event)
 Sends the event to the peer of the pad. More...
 
FlowReturn pull_range (guint64 offset, guint size, Glib::RefPtr< Gst::Buffer >& buffer)
 Pulls a buffer from the peer pad. More...
 
bool activate_mode (Gst::PadMode mode, bool active=true)
 Activates or deactivates the given pad in mode via dispatching to the pad's activatemodefunc. More...
 
bool send_event (const Glib::RefPtr< Gst::Event >& event)
 Sends the event to the pad. More...
 
bool event_default (const Glib::RefPtr< Gst::Object >& parent, const Glib::RefPtr< Gst::Event >& event)
 Invokes the default event handler for the given pad. More...
 
bool event_default (const Glib::RefPtr< Gst::Event >& event)
 A event_default() convenience overload. More...
 
bool query (const Glib::RefPtr< Gst::Query >& query) const
 Dispatches a query to a pad. More...
 
bool peer_query (const Glib::RefPtr< Gst::Query >&query) const
 Performs query() on the peer of pad. More...
 
Glib::RefPtr< Gst::Capspeer_query_caps (const Glib::RefPtr< Gst::Caps >& filter) const
 Gets the capabilities of the peer connected to this pad. More...
 
bool query_default (const Glib::RefPtr< Gst::Object >& parent, const Glib::RefPtr< Gst::Query >&query) const
 Invokes the default query handler for the given pad. More...
 
bool query_default (const Glib::RefPtr< Gst::Query >&query) const
 A query_default() convenience overload. More...
 
bool query_position (Format format, gint64& position) const
 Queries a pad for the stream position. More...
 
bool query_position (Format& format) const
 Queries a pad for the stream position parsing only the format. More...
 
bool query_duration (Format format, gint64& duration) const
 Queries a pad for the total stream duration. More...
 
bool query_duration (Format& format) const
 Queries a pad for the total stream duration parsing only the format. More...
 
bool query_convert (Format src_format, gint64 src_value, Format dst_format, gint64& dst_value) const
 Queries a pad to convert src_val in src_format to dest_format. More...
 
bool peer_query_convert (Format src_format, gint64 src_value, Format dst_format, gint64& dst_value) const
 Queries the peer pad of a given sink pad to convert src_val in src_format to dest_format. More...
 
Gst::Iterator< Gst::Paditerate_internal_links ()
 Gets an iterator for the pads to which the given pad is linked to inside of the parent element. More...
 
Gst::Iterator< const Gst::Paditerate_internal_links () const
 Gets an iterator for the pads to which the given pad is linked to inside of the parent element. More...
 
Gst::Iterator< Gst::Paditerate_internal_links_default (const Glib::RefPtr< Gst::Object >& parent)
 Iterate the list of pads to which the given pad is linked to inside of the parent element. More...
 
Gst::Iterator< Gst::Paditerate_internal_links_default ()
 A iterate_internal_links_default() convenience overload. More...
 
Gst::Iterator< const Gst::Paditerate_internal_links_default (const Glib::RefPtr< Gst::Object >& parent) const
 Iterate the list of pads to which the given pad is linked to inside of the parent element. More...
 
Gst::Iterator< const Gst::Paditerate_internal_links_default () const
 A iterate_internal_links_default() convenience overload. More...
 
FlowReturn chain (Glib::RefPtr< Gst::Buffer >& buffer)
 
Glib::RefPtr< Gst::Capsget_current_caps ()
 Gets the capabilities currently configured on pad with the last Gst::EVENT_CAPS event. More...
 
bool pause_task ()
 Pause the task of pad. More...
 
bool stop_task ()
 Stop the task of pad. More...
 
bool set_active (bool active=true)
 Activates or deactivates the given pad. More...
 
Glib::RefPtr< Gst::Eventget_sticky_event (Gst::EventType event_type, guint idx) const
 Returns a new reference of the sticky event of type event_type from the event. More...
 
void set_chain_function (const SlotChain& slot)
 
void set_event_function (const SlotEvent& slot)
 
void set_query_function (const SlotQuery& slot)
 
void set_activate_function (const SlotActivate& slot)
 
void set_activatemode_function (const SlotActivatemode& slot)
 
void set_getrange_function (const SlotGetrange& slot)
 
Glib::SignalProxy1< void,
const Glib::RefPtr< Gst::Pad >& > 
signal_linked ()
 
Glib::SignalProxy1< void,
const Glib::RefPtr< Gst::Pad >& > 
signal_unlinked ()
 
Glib::PropertyProxy_ReadOnly
< Glib::RefPtr< Gst::Caps > > 
property_caps () const
 The capabilities of the pad. More...
 
Glib::PropertyProxy_ReadOnly
< PadDirection
property_direction () const
 The direction of the pad. More...
 
Glib::PropertyProxy< PadTemplateproperty_template ()
 The GstPadTemplate of this pad. More...
 
Glib::PropertyProxy_ReadOnly
< PadTemplate
property_template () const
 The GstPadTemplate of this pad. More...
 
bool is_ghost_pad () const
 Checks whether pad is a ghostpad. More...
 
bool is_proxy_pad () const
 
void exception_handler ()
 Handle exceptions occuring in callback methods. More...
 
- Public Member Functions inherited from Gst::Object
virtual ~Object ()
 
GstObject* gobj ()
 Provides access to the underlying C GObject. More...
 
const GstObject* gobj () const
 Provides access to the underlying C GObject. More...
 
GstObject* gobj_copy ()
 Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs. More...
 
bool is_element () const
 
bool is_element_factory () const
 
bool is_pad () const
 
bool is_pad_template () const
 
bool is_bin () const
 
guint32 get_flags () const
 Returns the entire set of flags for the object. More...
 
bool set_name (const Glib::ustring& name)
 Sets the name of object, or gives object a guaranteed unique name (if name is 0). More...
 
Glib::ustring get_name () const
 Returns a copy of the name of object. More...
 
bool set_parent (const Glib::RefPtr< Gst::Object >& parent)
 Sets the parent of object to parent. More...
 
Glib::RefPtr< Gst::Objectget_parent ()
 Returns the parent of object. More...
 
Glib::RefPtr< const Gst::Objectget_parent () const
 Returns the parent of object. More...
 
void unparent ()
 Clear the parent of object, removing the associated reference. More...
 
bool has_ancestor (const Glib::RefPtr< const Gst::Object >& ancestor) const
 Check if object has an ancestor ancestor somewhere up in the hierarchy. More...
 
Glib::ustring get_path_string ()
 Generates a string describing the path of object in the object hierarchy. More...
 
Glib::PropertyProxy
< Glib::ustring
property_name ()
 The name of the object. More...
 
Glib::PropertyProxy_ReadOnly
< Glib::ustring
property_name () const
 The name of the object. More...
 
Glib::SignalProxy2< void,
const Glib::RefPtr< Object >
&, GParamSpec* > 
signal_deep_notify ()
 
int get_refcount () const
 

Static Public Member Functions

static GType get_type ()
 Get the GType for this class, for use with the underlying GObject type system. More...
 
static Glib::RefPtr< Padcreate (const Glib::ustring& name, PadDirection dir)
 Creates a new pad with the given name in the given direction. More...
 
static Glib::RefPtr< Padcreate (PadDirection dir)
 Creates a new pad with a guaranteed unique name (across all pads) in the given direction. More...
 
static Glib::RefPtr< Padcreate (const Glib::RefPtr< const Gst::PadTemplate >& pad_template)
 Creates a new pad with the given name from the given template. More...
 
static Glib::RefPtr< Padcreate (const Glib::RefPtr< const Gst::PadTemplate >& pad_template, const Glib::ustring& name)
 Creates a new pad with a guaranteed unique name (across all pads) from the given template. More...
 
static GstFlowReturn Pad_Chain_gstreamermm_callback (GstPad* pad, GstObject* parent, GstBuffer* buffer)
 
static gboolean Pad_Event_gstreamermm_callback (GstPad* pad, GstObject* parent, GstEvent* event)
 
static gboolean Pad_Query_gstreamermm_callback (GstPad* pad, GstObject* parent, GstQuery*query)
 
static gboolean Pad_Activate_gstreamermm_callback (GstPad* pad, GstObject* parent)
 
static gboolean Pad_Activatemode_gstreamermm_callback (GstPad* pad, GstObject* parent, GstPadMode mode, gboolean active)
 
static GstFlowReturn Pad_Getrange_gstreamermm_callback (GstPad* pad, GstObject* parent, guint64 offset, guint length, GstBuffer** buffer)
 
- Static Public Member Functions inherited from Gst::Object
static GType get_type ()
 Get the GType for this class, for use with the underlying GObject type system. More...
 
static bool check_uniqueness (const Glib::ListHandle< const Gst::Object >& list, const Glib::ustring& name)
 Checks to see if there is any object named name in list. More...
 

Protected Member Functions

 Pad (const Glib::ustring& name, PadDirection direction)
 Constructs a Pad given a name and a direction. More...
 
 Pad (PadDirection direction)
 Constructs a Pad given a direction without specifying a name. More...
 
 Pad (const Glib::RefPtr< const Gst::PadTemplate >& templ, const Glib::ustring& name)
 Constructs a Pad from a PadTemplate with the specified name. More...
 
 Pad (const Glib::RefPtr< const Gst::PadTemplate >& templ)
 Constructs a Pad from a PadTemplate without specifying a name. More...
 
virtual void on_linked (const Glib::RefPtr< Gst::Pad >& peer_pad)
 This is a default handler for the signal signal_linked(). More...
 
virtual void on_unlinked (const Glib::RefPtr< Gst::Pad >& peer_pad)
 This is a default handler for the signal signal_unlinked(). More...
 
- Protected Member Functions inherited from Gst::Object
virtual void on_deep_notify (const Glib::RefPtr< Object >& prop_object, GParamSpec* prop)
 This is a default handler for the signal signal_deep_notify(). More...
 

Related Functions

(Note that these are not member functions.)

Glib::RefPtr< Gst::Padwrap (GstPad* object, bool take_copy=false)
 A Glib::wrap() method for this object. More...
 

Detailed Description

A class that represents objects contained by elements that allows links to other elements.

A Gst::Element is linked to other elements via "pads", which are extremely light-weight generic link points. After two pads are retrieved from an element with Element::get_pad(), the pads can be link with link(). (For quick links, you can also use Element::link(), which will make the obvious link for you if it's straightforward.)

Pads are typically created from a Gst::PadTemplate with the create() method that takes a Gst::PadTemplate.

Pads without pad templates can be created with create(), which takes a direction and a name as an argument.

get_parent_element() will retrieve the Gst::Element that owns the pad.

A Gst::Element creating a pad will typically use the underlying C API to register callbacks for various events on the pads.

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

To send a Gst::Event on a pad, use send_event() and push_event().

Last reviewed on 2006-07-06 (0.10.9)

Member Typedef Documentation

typedef sigc::slot< bool, const Glib::RefPtr<Gst::Pad>& > Gst::Pad::SlotActivate
typedef sigc::slot< bool, const Glib::RefPtr<Gst::Pad>&, Gst::PadMode, bool > Gst::Pad::SlotActivatemode
typedef sigc::slot< gboolean, const Glib::RefPtr<Gst::Pad>&, Glib::RefPtr<Gst::Event>& > Gst::Pad::SlotEvent
typedef sigc::slot< Gst::FlowReturn, const Glib::RefPtr<Gst::Pad>&, guint64, guint, Glib::RefPtr<Gst::Buffer>& > Gst::Pad::SlotGetrange

For example, bool on_have_data(const Glib::RefPtr<Gst::Pad>& pad, const Glib::RefPtr<Gst::MiniObjec>& data);.

typedef sigc::slot< gboolean, const Glib::RefPtr<Gst::Pad>&, const Glib::RefPtr<Gst::Query>& > Gst::Pad::SlotQuery

Constructor & Destructor Documentation

virtual Gst::Pad::~Pad ( )
virtual
Gst::Pad::Pad ( const Glib::ustring name,
PadDirection  direction 
)
explicitprotected

Constructs a Pad given a name and a direction.

Parameters
nameThe desired name of the pad.
directionThe desired direction of the pad.
Gst::Pad::Pad ( PadDirection  direction)
explicitprotected

Constructs a Pad given a direction without specifying a name.

A unique name will be assigned to the pad.

Parameters
directionthe direction of the pad.
Gst::Pad::Pad ( const Glib::RefPtr< const Gst::PadTemplate >&  templ,
const Glib::ustring name 
)
protected

Constructs a Pad from a PadTemplate with the specified name.

Parameters
templThe PadTemplate.
nameThe desired name of the pad.
Exceptions
std::runtime_errorif construction fails.
Gst::Pad::Pad ( const Glib::RefPtr< const Gst::PadTemplate >&  templ)
explicitprotected

Constructs a Pad from a PadTemplate without specifying a name.

A unique name will ge assigned to the pad.

Parameters
templThe PadTemplate.
Exceptions
std::runtime_errorif construction fails.

Member Function Documentation

bool Gst::Pad::activate_mode ( Gst::PadMode  mode,
bool  active = true 
)

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
modeThe requested activation mode.
activeWhether or not the pad should be active.
Returns
true if the operation was successful.

MT safe.

gulong Gst::Pad::add_probe ( PadProbeType  mask,
const SlotProbe slot 
)
bool Gst::Pad::can_link ( const Glib::RefPtr< const Gst::Pad >&  other_pad) const

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

Parameters
sinkpadThe sink Gst::Pad.
Returns
true if the pads can be linked.
FlowReturn Gst::Pad::chain ( Glib::RefPtr< Gst::Buffer >&  buffer)
static Glib::RefPtr<Pad> Gst::Pad::create ( const Glib::ustring name,
PadDirection  dir 
)
static

Creates a new pad with the given name in the given direction.

Parameters
nameThe name of the new pad.
directionThe GstPadDirection of the pad.
Returns
A new Gst::Pad, or a null RefPtr<> in case of an error. MT safe.
static Glib::RefPtr<Pad> Gst::Pad::create ( PadDirection  dir)
static

Creates a new pad with a guaranteed unique name (across all pads) in the given direction.

Parameters
directionThe GstPadDirection of the pad.
Returns
A new Gst::Pad, or a null RefPtr<> in case of an error. MT safe.
static Glib::RefPtr<Pad> Gst::Pad::create ( const Glib::RefPtr< const Gst::PadTemplate >&  pad_template)
static

Creates a new pad with the given name from the given template.

Parameters
templThe pad template to use.
nameThe name of the element.
Returns
A new Gst::Pad, or a null RefPtr<> in case of an error.
Exceptions
std::runtime_errorif construction fails.
static Glib::RefPtr<Pad> Gst::Pad::create ( const Glib::RefPtr< const Gst::PadTemplate >&  pad_template,
const Glib::ustring name 
)
static

Creates a new pad with a guaranteed unique name (across all pads) from the given template.

Parameters
templThe pad template to use.
Returns
A new Gst::Pad, or a null RefPtr<> in case of an error.
Exceptions
std::runtime_errorif construction fails.
bool Gst::Pad::event_default ( const Glib::RefPtr< Gst::Object >&  parent,
const Glib::RefPtr< Gst::Event >&  event 
)

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

Parameters
parentThe parent of pad or 0.
eventThe Gst::Event to handle.
Returns
true if the event was sent successfully.
bool Gst::Pad::event_default ( const Glib::RefPtr< Gst::Event >&  event)

A event_default() convenience overload.

void Gst::Pad::exception_handler ( )

Handle exceptions occuring in callback methods.

Glib::RefPtr<Gst::Caps> Gst::Pad::get_allowed_caps ( )

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.

Returns
The allowed Gst::Caps of the pad link. Unref the caps when you no longer need it. This function returns 0 when pad has no peer.

MT safe.

Glib::RefPtr<const Gst::Caps> Gst::Pad::get_allowed_caps ( ) const

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.

Returns
The allowed Gst::Caps of the pad link. Unref the caps when you no longer need it. This function returns 0 when pad has no peer.

MT safe.

Glib::RefPtr<Gst::Caps> Gst::Pad::get_current_caps ( )

Gets the capabilities currently configured on pad with the last Gst::EVENT_CAPS event.

Returns
The current caps of the pad with incremented ref-count.
PadDirection Gst::Pad::get_direction ( ) const

Gets the direction of the pad.

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

Returns
The Gst::PadDirection of the pad.

MT safe.

Glib::RefPtr<Gst::PadTemplate> Gst::Pad::get_pad_template ( )

Gets the template for pad.

Returns
The Gst::PadTemplate from which this pad was instantiated, or 0 if this pad has no template. Unref after usage.
Glib::RefPtr<const Gst::PadTemplate> Gst::Pad::get_pad_template ( ) const

Gets the template for pad.

Returns
The Gst::PadTemplate from which this pad was instantiated, or 0 if this pad has no template. Unref after usage.
Glib::RefPtr<const Gst::Caps> Gst::Pad::get_pad_template_caps ( ) const

Gets the capabilities for pad's template.

Returns
The Gst::Caps of this pad template.
Glib::RefPtr<Gst::Element> Gst::Pad::get_parent_element ( )

Gets the parent of pad, cast to a Gst::Element.

If a pad has no parent or its parent is not an element, return 0.

Returns
The parent of the pad. The caller has a reference on the parent, so unref when you're finished with it.

MT safe.

Glib::RefPtr<const Gst::Element> Gst::Pad::get_parent_element ( ) const

Gets the parent of pad, cast to a Gst::Element.

If a pad has no parent or its parent is not an element, return 0.

Returns
The parent of the pad. The caller has a reference on the parent, so unref when you're finished with it.

MT safe.

Glib::RefPtr<Gst::Pad> Gst::Pad::get_peer ( )

Gets the peer of pad.

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

Returns
The peer Gst::Pad. Unref after usage.

MT safe.

Glib::RefPtr<const Gst::Pad> Gst::Pad::get_peer ( ) const

Gets the peer of pad.

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

Returns
The peer Gst::Pad. Unref after usage.

MT safe.

FlowReturn Gst::Pad::get_range ( guint64  offset,
guint  size,
Glib::RefPtr< Gst::Buffer >&  buffer 
)

When pad is flushing this function returns Gst::FLOW_WRONG_STATE immediatly.

Calls the getrange function of pad. If pad has no getrange function installed this function returns Gst::FLOW_NOT_SUPPORTED.

This is a lowlevel function. Usually pull_range() is used. This function is designed to be used with a source pad only.

Parameters
offsetThe start offset of the buffer.
sizeThe length of the buffer.
bufferAn unitialized Glib::RefPtr<> in which to store the Gst::Buffer.
Returns
A Gst::FlowReturn from the pad (Gst::FLOW_NOT_SUPPORTED if pad is not a source pad). MT safe.
Glib::RefPtr<Gst::Event> Gst::Pad::get_sticky_event ( Gst::EventType  event_type,
guint  idx 
) const

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

Parameters
event_typeThe Gst::EventType that should be retrieved.
idxThe index of the event.
Returns
A Gst::Event of type event_type or 0 when no event of event_type was on pad. Unref after usage.
static GType Gst::Pad::get_type ( )
static

Get the GType for this class, for use with the underlying GObject type system.

GstPad* Gst::Pad::gobj ( )
inline

Provides access to the underlying C GObject.

const GstPad* Gst::Pad::gobj ( ) const
inline

Provides access to the underlying C GObject.

GstPad* Gst::Pad::gobj_copy ( )

Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs.

bool Gst::Pad::is_active ( ) const

Query if a pad is active.

Returns
true if the pad is active.

MT safe.

bool Gst::Pad::is_blocked ( ) const

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()).

Returns
true if the pad is blocked.

MT safe.

bool Gst::Pad::is_blocking ( ) const

Checks if the pad is blocking or not.

This is a guaranteed state of whether the pad is actually blocking on a Gst::Buffer or a Gst::Event.

Returns
true if the pad is blocking.

MT safe.

bool Gst::Pad::is_ghost_pad ( ) const

Checks whether pad is a ghostpad.

bool Gst::Pad::is_linked ( ) const

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

Returns
true if the pad is linked, false otherwise.

MT safe.

bool Gst::Pad::is_proxy_pad ( ) const
Gst::Iterator<Gst::Pad> Gst::Pad::iterate_internal_links ( )

Gets an iterator for the pads to which the given pad is linked to inside of the parent element.

Each Gst::Pad element yielded by the iterator will have its refcount increased, so unref after use.

Free-function: gst_iterator_free

Returns
A new Gst::Iterator of Gst::Pad or 0 when the pad does not have an iterator function configured. Use Gst::Iterator::free() after usage.
Gst::Iterator<const Gst::Pad> Gst::Pad::iterate_internal_links ( ) const

Gets an iterator for the pads to which the given pad is linked to inside of the parent element.

Each Gst::Pad element yielded by the iterator will have its refcount increased, so unref after use.

Free-function: gst_iterator_free

Returns
A new Gst::Iterator of Gst::Pad or 0 when the pad does not have an iterator function configured. Use Gst::Iterator::free() after usage.
Gst::Iterator<Gst::Pad> Gst::Pad::iterate_internal_links_default ( const Glib::RefPtr< Gst::Object >&  parent)

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().

Parameters
parentThe parent of pad or 0.
Returns
A Gst::Iterator of Gst::Pad, or 0 if pad has no parent. Unref each returned pad with Gst::Object::unref().
Gst::Iterator<Gst::Pad> Gst::Pad::iterate_internal_links_default ( )

A iterate_internal_links_default() convenience overload.

Gst::Iterator<const Gst::Pad> Gst::Pad::iterate_internal_links_default ( const Glib::RefPtr< Gst::Object >&  parent) const

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().

Parameters
parentThe parent of pad or 0.
Returns
A Gst::Iterator of Gst::Pad, or 0 if pad has no parent. Unref each returned pad with Gst::Object::unref().
Gst::Iterator<const Gst::Pad> Gst::Pad::iterate_internal_links_default ( ) const

A iterate_internal_links_default() convenience overload.

PadLinkReturn Gst::Pad::link ( const Glib::RefPtr< Gst::Pad >&  sink_pad)

Links the source pad and the sink pad.

Parameters
sinkpadThe sink Gst::Pad to link.
Returns
A result code indicating if the connection worked or what went wrong.

MT Safe.

virtual void Gst::Pad::on_linked ( const Glib::RefPtr< Gst::Pad >&  peer_pad)
protectedvirtual

This is a default handler for the signal signal_linked().

virtual void Gst::Pad::on_unlinked ( const Glib::RefPtr< Gst::Pad >&  peer_pad)
protectedvirtual

This is a default handler for the signal signal_unlinked().

static gboolean Gst::Pad::Pad_Activate_gstreamermm_callback ( GstPad *  pad,
GstObject *  parent 
)
static
static gboolean Gst::Pad::Pad_Activatemode_gstreamermm_callback ( GstPad *  pad,
GstObject *  parent,
GstPadMode  mode,
gboolean  active 
)
static
static GstFlowReturn Gst::Pad::Pad_Chain_gstreamermm_callback ( GstPad *  pad,
GstObject *  parent,
GstBuffer *  buffer 
)
static
static gboolean Gst::Pad::Pad_Event_gstreamermm_callback ( GstPad *  pad,
GstObject *  parent,
GstEvent *  event 
)
static
static GstFlowReturn Gst::Pad::Pad_Getrange_gstreamermm_callback ( GstPad *  pad,
GstObject *  parent,
guint64  offset,
guint  length,
GstBuffer **  buffer 
)
static
static gboolean Gst::Pad::Pad_Query_gstreamermm_callback ( GstPad *  pad,
GstObject *  parent,
GstQuery *  query 
)
static
bool Gst::Pad::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.

Returns
A true if the task could be paused or false when the pad has no task.
bool Gst::Pad::peer_query ( const Glib::RefPtr< Gst::Query >&  query) const

Performs query() on the peer of pad.

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

Parameters
queryThe Gst::Query to perform.
Returns
true if the query could be performed. This function returns false if pad has no peer.
bool Gst::Pad::peer_query_accept_caps ( const Glib::RefPtr< const Gst::Caps >&  caps) const

Check if the peer of pad accepts caps.

If pad has no peer, this function returns true.

Parameters
capsA Gst::Caps to check on the pad.
Returns
true if the peer of pad can accept the caps or pad has no peer.
Glib::RefPtr<Gst::Caps> Gst::Pad::peer_query_caps ( const Glib::RefPtr< Gst::Caps >&  filter) const

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 preffered order. filter might be 0 but if it is not 0 the returned caps will be a subset of filter.

Parameters
filterA Gst::Caps filter, or 0.
Returns
The caps of the peer pad with incremented ref-count. When there is no peer pad, this function returns filter or, when filter is 0, ANY caps.
bool Gst::Pad::peer_query_convert ( Format  src_format,
gint64  src_value,
Format  dst_format,
gint64 &  dst_value 
) const

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

Parameters
src_formatA Gst::Format to convert from.
src_valA value to convert.
dest_formatThe Gst::Format to convert to.
dest_valA pointer to the result.
Returns
true if the query could be performed.
Glib::PropertyProxy_ReadOnly< Glib::RefPtr<Gst::Caps> > Gst::Pad::property_caps ( ) const

The capabilities of the pad.

You rarely need to use properties because there are get_ and set_ methods for almost all of them.

Returns
A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.
Glib::PropertyProxy_ReadOnly< PadDirection > Gst::Pad::property_direction ( ) const

The direction of the pad.

You rarely need to use properties because there are get_ and set_ methods for almost all of them.

Returns
A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.
Glib::PropertyProxy< PadTemplate > Gst::Pad::property_template ( )

The GstPadTemplate of this pad.

You rarely need to use properties because there are get_ and set_ methods for almost all of them.

Returns
A PropertyProxy that allows you to get or set the value of the property, or receive notification when the value of the property changes.
Glib::PropertyProxy_ReadOnly< PadTemplate > Gst::Pad::property_template ( ) const

The GstPadTemplate of this pad.

You rarely need to use properties because there are get_ and set_ methods for almost all of them.

Returns
A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.
bool Gst::Pad::proxy_query_caps ( const Glib::RefPtr< Gst::Query >&  query)

Calls query_caps() for all internally linked pads fof 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
queryA CAPS Gst::Query.
Returns
true if query could be executed.
bool Gst::Pad::proxy_query_caps ( const Glib::RefPtr< Gst::Query >&  query) const

Calls query_caps() for all internally linked pads fof 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
queryA CAPS Gst::Query.
Returns
true if query could be executed.
FlowReturn Gst::Pad::pull_range ( guint64  offset,
guint  size,
Glib::RefPtr< Gst::Buffer >&  buffer 
)

Pulls a buffer from the peer pad.

This function will first trigger the pad block signal if it was installed. This method works only on sink pads.

When pad is not linked Gst::FLOW_NOT_LINKED is returned else this function returns the result of get_range() on the peer pad.

buffer's caps must either be unset or the same as what is already configured on pad. Renegotiation within a running pull-mode pipeline is not supported.

Parameters
offsetThe start offset of the buffer.
sizeThe length of the buffer.
bufferAn uninitialized Glib::RefPtr<> in which to hold the Gst::Buffer.
Returns
A Gst::FlowReturn from the peer pad (Gst::FLOW_ERROR if pad is not a sink pad). When this function returns Gst::FLOW_OK, buffer will contain a valid Gst::Buffer. buffer may not be used when any other return value than Gst::FLOW_OK is returned. MT safe.
FlowReturn Gst::Pad::push ( Glib::RefPtr< Gst::Buffer >&  buffer)

Pushes a buffer to the peer of the pad.

The pad must be a source pad, otherwise this method returns Gst::FLOW_ERROR.

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 pad, this function will call any installed setcaps function on pad (see the C API gst_pad_set_setcaps_function()). In case of failure to renegotiate the new format, this function returns Gst::FLOW_NOT_NEGOTIATED.

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.

Parameters
bufferThe Gst::Buffer to push.
Returns
A Gst::FlowReturn from the peer pad. MT safe.
bool Gst::Pad::push_event ( const Glib::RefPtr< Gst::Event >&  event)

Sends the event to the peer of the pad.

This function is mainly used by elements to send events to their peer elements.

Parameters
eventThe GstEvent to send to the pad.
Returns
true if the event was handled. MT safe.
bool Gst::Pad::query ( const Glib::RefPtr< Gst::Query >&  query) const

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
queryThe Gst::Query to perform.
Returns
true if the query could be performed.
bool Gst::Pad::query_accept_caps ( const Glib::RefPtr< const Gst::Caps >&  caps) const

Check if the given pad accepts the caps.

Parameters
capsA Gst::Caps to check on the pad.
Returns
true if the pad can accept the caps.
Glib::RefPtr<Gst::Caps> Gst::Pad::query_caps ( Glib::RefPtr< Gst::Caps caps)

Gets the capabilities this pad can produce or consume.

Note that this method doesn't necessarily return the caps set by sending a gst_event_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 #0, 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 preffered order. filter might be 0 but if it is not 0 the returned caps will be a subset of filter.

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

Parameters
filterSuggested Gst::Caps, or 0.
Returns
The caps of the pad with incremented ref-count.
Glib::RefPtr<const Gst::Caps> Gst::Pad::query_caps ( Glib::RefPtr< Gst::Caps caps) const

Gets the capabilities this pad can produce or consume.

Note that this method doesn't necessarily return the caps set by sending a gst_event_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 #0, 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 preffered order. filter might be 0 but if it is not 0 the returned caps will be a subset of filter.

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

Parameters
filterSuggested Gst::Caps, or 0.
Returns
The caps of the pad with incremented ref-count.
bool Gst::Pad::query_convert ( Format  src_format,
gint64  src_value,
Format  dst_format,
gint64 &  dst_value 
) const

Queries a pad to convert src_val in src_format to dest_format.

Parameters
src_formatA Gst::Format to convert from.
src_valA value to convert.
dest_formatThe Gst::Format to convert to.
dest_valA pointer to the result.
Returns
true if the query could be performed.
bool Gst::Pad::query_default ( const Glib::RefPtr< Gst::Object >&  parent,
const Glib::RefPtr< Gst::Query >&  query 
) const

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
parentThe parent of pad or 0.
queryThe Gst::Query to handle.
Returns
true if the query was performed successfully.
bool Gst::Pad::query_default ( const Glib::RefPtr< Gst::Query >&  query) const

A query_default() convenience overload.

bool Gst::Pad::query_duration ( Format  format,
gint64 &  duration 
) const

Queries a pad for the total stream duration.

Parameters
formatThe Gst::Format requested.
durationA location in which to store the total duration, or 0.
Returns
true if the query could be performed.
bool Gst::Pad::query_duration ( Format format) const

Queries a pad for the total stream duration parsing only the format.

Parameters
formatA reference to the Gst::Format asked for. On return contains the GstFormat used.
Returns
true if the query could be performed.
bool Gst::Pad::query_position ( Format  format,
gint64 &  position 
) const

Queries a pad for the stream position.

Parameters
formatThe Gst::Format requested.
curA location in which to store the current position, or 0.
Returns
true if the query could be performed.
bool Gst::Pad::query_position ( Format format) const

Queries a pad for the stream position parsing only the format.

Parameters
formatA reference to the Gst::Format asked for. On return contains the Gst::Format used.
Returns
true if the query could be performed.
void Gst::Pad::remove_probe ( gulong  id)

Remove the probe with id from pad.

MT safe.

Parameters
idThe probe id to remove.
bool Gst::Pad::send_event ( const Glib::RefPtr< Gst::Event >&  event)

Sends the event to the pad.

This function can be used by applications to send events in the pipeline.

If the pad is a source pad, event should be an upstream event. If the pad is a sink pad, the 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 Gst::EventTypeFlags, Gst::Enums::get_flags(), 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.

Parameters
eventThe Gst::Event to send to the pad.
Returns
true if the event was handled.
void Gst::Pad::set_activate_function ( const SlotActivate slot)
void Gst::Pad::set_activatemode_function ( const SlotActivatemode slot)
bool Gst::Pad::set_active ( bool  active = true)

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
activeWhether or not the pad should be active.
Returns
#true if the operation was successful.

MT safe.

void Gst::Pad::set_chain_function ( const SlotChain slot)
void Gst::Pad::set_event_function ( const SlotEvent slot)
void Gst::Pad::set_getrange_function ( const SlotGetrange slot)
void Gst::Pad::set_query_function ( const SlotQuery slot)
Glib::SignalProxy1< void,const Glib::RefPtr<Gst::Pad>& > Gst::Pad::signal_linked ( )
Slot Prototype:
void on_my_linked(const Glib::RefPtr<Gst::Pad>& peer_pad)

Signals that a pad has been linked to the peer pad.

Parameters
peerThe peer pad that has been connected.
Glib::SignalProxy1< void,const Glib::RefPtr<Gst::Pad>& > Gst::Pad::signal_unlinked ( )
Slot Prototype:
void on_my_unlinked(const Glib::RefPtr<Gst::Pad>& peer_pad)

Signals that a pad has been unlinked from the peer pad.

Parameters
peerThe peer pad that has been disconnected.
bool Gst::Pad::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 Gst::Task::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.

Returns
A true if the task could be stopped or false on error.
bool Gst::Pad::unlink ( const Glib::RefPtr< Gst::Pad >&  sink_pad)

Unlinks the source pad from the sink pad.

Will emit the Gst::Pad::signal_unlinked() signal on both pads.

Parameters
sinkpadThe sink Gst::Pad to unlink.
Returns
true if the pads were unlinked. This function returns false if the pads were not linked together.

MT safe.

void Gst::Pad::use_fixed_caps ( )

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.

Friends And Related Function Documentation

Glib::RefPtr< Gst::Pad > wrap ( GstPad *  object,
bool  take_copy = false 
)
related

A Glib::wrap() method for this object.

Parameters
objectThe C instance.
take_copyFalse if the result should take ownership of the C instance. True if it should take a new copy or ref.
Returns
A C++ instance that wraps this C instance.

The documentation for this class was generated from the following file: