gstreamermm: Gst::BaseTransform Class Reference

A base class for simple transform filters. More...

Inheritance diagram for Gst::BaseTransform:
Collaboration diagram for Gst::BaseTransform:

Public Member Functions

virtual ~BaseTransform ()
 
GstBaseTransform* gobj ()
 Provides access to the underlying C GObject. More...

 
const GstBaseTransform* gobj () const
 Provides access to the underlying C GObject. More...

 
GstBaseTransform* 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_passthrough () const
 See if trans is configured as a passthrough transform. More...

 
void set_passthrough (bool passthrough)
 Set passthrough mode for this filter by default. More...

 
bool is_in_place () const
 See if trans is configured as a in_place transform. More...

 
void set_in_place (bool in_place)
 Determines whether a non-writable buffer will be copied before passing to the transform_ip function. More...

 
bool is_qos_enabled () const
 Queries if the transform will handle QoS. More...

 
void set_qos_enabled (bool enabled)
 Enable or disable QoS handling in the transform. More...

 
void update_qos (double proportion, ClockTimeDiff diff, ClockTime timestamp)
 Set the QoS parameters in the transform. More...

 
void set_gap_aware (bool gap_aware)
 If gap_aware is false (the default), output buffers will have the Gst::BUFFER_FLAG_GAP flag unset. More...

 
Glib::RefPtr< Gst::Padget_sink_pad ()
 Gives the refptr to the sink Gst::Pad object of the element. More...

 
Glib::RefPtr< const Gst::Padget_sink_pad () const
 
Glib::RefPtr< Gst::Padget_src_pad ()
 Gives the refptr to the source Gst::Pad object of the element. More...

 
Glib::RefPtr< const Gst::Padget_src_pad () const
 
Glib::PropertyProxy< bool > property_qos ()
 Handle Quality-of-Service events. More...

 
Glib::PropertyProxy_ReadOnly

< bool > 
property_qos () const
 Handle Quality-of-Service events. More...

 
virtual Glib::RefPtr< Gst::Capstransform_caps_vfunc (PadDirection direction, const Glib::RefPtr< Gst::Caps >& caps, const Glib::RefPtr< Gst::Caps >& filter)
 Optional. More...

 
virtual Glib::RefPtr< Gst::Capsfixate_caps_vfunc (PadDirection direction, const Glib::RefPtr< Gst::Caps >& caps, const Glib::RefPtr< Gst::Caps >& othercaps)
 Optional. More...

 
virtual bool get_unit_size_vfunc (const Glib::RefPtr< Gst::Caps >& caps, gsize&size) const
 Optional. More...

 
virtual bool set_caps_vfunc (const Glib::RefPtr< Gst::Caps >& incaps, const Glib::RefPtr< Gst::Caps >& outcaps)
 Allows the subclass to be notified of the actual caps set. More...

 
virtual FlowReturn transform_vfunc (const Glib::RefPtr< Gst::Buffer >& inbuf, const Glib::RefPtr< Gst::Buffer >& outbuf)
 Required if the element does not operate in-place. More...

 
virtual FlowReturn transform_ip_vfunc (const Glib::RefPtr< Gst::Buffer >& buf)
 Required if the element operates in-place. More...

 
virtual FlowReturn prepare_output_buffer_vfunc (const Glib::RefPtr< Gst::Buffer >& input, Glib::RefPtr< Gst::Buffer >& buffer)
 Optional. More...

 
virtual bool src_event_vfunc (const Glib::RefPtr< Gst::Event >& event)
 Optional. More...

 
virtual void before_transform_vfunc (const Glib::RefPtr< Gst::Buffer >& buffer)
 Optional. More...

 
virtual bool accept_caps_vfunc (PadDirection direction, const Glib::RefPtr< const Gst::Caps >& caps)
 Optional. More...

 
virtual bool start_vfunc ()
 Optional. More...

 
virtual bool stop_vfunc ()
 Optional. More...

 
- Public Member Functions inherited from Gst::Element
virtual ~Element ()
 
GstElement* gobj ()
 Provides access to the underlying C GObject. More...

 
const GstElement* gobj () const
 Provides access to the underlying C GObject. More...

 
GstElement* 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::Elementlink (const Glib::RefPtr< Gst::Element >& dest)
 Links this source element to the element. More...

 
bool add_pad (const Glib::RefPtr< Gst::Pad >& pad)
 Adds a pad (link point) to element. More...

 
void create_all_pads ()
 Creates a pad for each pad template that is always available. More...

 
Glib::RefPtr< Gst::Padcreate_compatible_pad (const Glib::RefPtr< const Gst::Pad >& pad, const Glib::RefPtr< const Gst::Caps >& caps)
 Looks for an unlinked pad to which the given pad can link. More...

 
Glib::RefPtr< Gst::PadTemplateget_compatible_pad_template (const Glib::RefPtr< const Gst::PadTemplate >& compattempl)
 Retrieves a pad template from element that is compatible with compattempl. More...

 
Glib::RefPtr< const

Gst::PadTemplate
get_compatible_pad_template (const Glib::RefPtr< const Gst::PadTemplate >& compattempl) const
 Retrieves a pad template from element that is compatible with compattempl. More...

 
Glib::RefPtr< Gst::Padget_request_pad (const Glib::ustring& name)
 Retrieves a pad from the element by name (e.g. "src_\\%d"). More...

 
Glib::RefPtr< Gst::Padrequest_pad (const Glib::RefPtr< Gst::PadTemplate >& templ, const Glib::ustring& name, const Glib::RefPtr< const Gst::Caps >& caps)
 Retrieves a request pad from the element according to the provided template. More...

 
Glib::RefPtr< Gst::Padrequest_pad (const Glib::RefPtr< Gst::PadTemplate >& templ, const Glib::ustring& name)
 A request_pad() convenience overload. More...

 
Glib::RefPtr< Gst::Padrequest_pad (const Glib::RefPtr< Gst::PadTemplate >& templ, const Glib::RefPtr< const Gst::Caps >& caps)
 A request_pad() convenience overload. More...

 
Glib::RefPtr< Gst::Padrequest_pad (const Glib::RefPtr< Gst::PadTemplate >& templ)
 A request_pad() convenience overload. More...

 
Glib::RefPtr< Gst::Padget_static_pad (const Glib::ustring& name)
 Retrieves a pad from element by name. More...

 
Glib::RefPtr< const Gst::Padget_static_pad (const Glib::ustring& name) const
 Retrieves a pad from element by name. More...

 
void no_more_pads ()
 Use this function to signal that the element does not expect any more pads to show up in the current pipeline. More...

 
void release_request_pad (const Glib::RefPtr< Gst::Pad >& pad)
 Makes the element free the previously requested pad as obtained with get_request_pad(). More...

 
bool remove_pad (const Glib::RefPtr< Gst::Pad >& pad)
 Removes pad from element. More...

 
Gst::Iterator< Gst::Paditerate_pads ()
 Retrieves an iterator of element's pads. More...

 
Gst::Iterator< const Gst::Paditerate_pads () const
 Retrieves an iterator of element's pads. More...

 
Gst::Iterator< Gst::Paditerate_sink_pads ()
 Retrieves an iterator of element's sink pads. More...

 
Gst::Iterator< const Gst::Paditerate_sink_pads () const
 Retrieves an iterator of element's sink pads. More...

 
Gst::Iterator< Gst::Paditerate_src_pads ()
 Retrieves an iterator of element's source pads. More...

 
Gst::Iterator< const Gst::Paditerate_src_pads () const
 Retrieves an iterator of element's source pads. More...

 
void unlink (const Glib::RefPtr< Gst::Element >& dest)
 Unlinks all source pads of the source element with all sink pads of the sink element to which they are linked. More...

 
void set_context (const Glib::RefPtr< Gst::Context >& context)
 Sets the context of the element. More...

 
bool link_pads (const Glib::ustring& srcpadname, const Glib::RefPtr< Gst::Element >& dest, const Glib::ustring& destpadname)
 Links the two named pads of the source and destination elements. More...

 
void unlink_pads (const Glib::ustring& srcpadname, const Glib::RefPtr< Gst::Element >& dest, const Glib::ustring& destpadname)
 Unlinks the two named pads of the source and destination elements. More...

 
bool link_pads (const Glib::ustring& srcpadname, const Glib::RefPtr< Gst::Element >& dest, const Glib::ustring& destpadname, const Glib::RefPtr< Gst::Caps >& filter)
 Links the two named pads of the source and destination elements. More...

 
bool link_pads (const Glib::ustring& srcpadname, const Glib::RefPtr< Gst::Element >& dest, const Glib::ustring& destpadname, PadLinkCheck flags)
 Links the two named pads of the source and destination elements. More...

 
Glib::RefPtr< Gst::Elementlink (const Glib::RefPtr< Gst::Element >& dest, const Glib::RefPtr< Gst::Caps >& filter)
 Links src to dest using the given caps as filtercaps. More...

 
void set_base_time (ClockTime time)
 Set the base time of an element. More...

 
ClockTime get_base_time () const
 Returns the base time of the element. More...

 
void set_start_time (Gst::ClockTime time)
 Set the start time of an element. More...

 
Gst::ClockTime get_start_time () const
 Returns the start time of the element. More...

 
void set_bus (const Glib::RefPtr< Gst::Bus >& bus)
 Sets the bus of the element. More...

 
Glib::RefPtr< Gst::Busget_bus ()
 Returns the bus of the element. More...

 
Glib::RefPtr< const Gst::Busget_bus () const
 Returns the bus of the element. More...

 
Glib::RefPtr< Gst::ElementFactoryget_factory ()
 Retrieves the factory that was used to create this element. More...

 
Glib::RefPtr< const

Gst::ElementFactory
get_factory () const
 Retrieves the factory that was used to create this element. More...

 
bool set_clock (const Glib::RefPtr< Gst::Clock >& clock)
 Sets the clock for the element. More...

 
Glib::RefPtr< Gst::Clockget_clock ()
 Gets the currently configured clock of the element. More...

 
Glib::RefPtr< const Gst::Clockget_clock () const
 Gets the currently configured clock of the element. More...

 
Glib::RefPtr< Gst::Clockprovide_clock ()
 Get the clock provided by the given element. More...

 
Glib::RefPtr< const Gst::Clockprovide_clock () const
 Get the clock provided by the given element. More...

 
StateChangeReturn set_state (State state)
 Sets the state of the element. More...

 
StateChangeReturn get_state (State& state, State& pending, ClockTime timeout) const
 Gets the state of the element. More...

 
bool set_locked_state (gboolean locked_state)
 Locks the state of an element, so state changes of the parent don't affect this element anymore. More...

 
bool is_locked_state () const
 Checks if the state of an element is locked. More...

 
void abort_state ()
 Abort the state change of the element. More...

 
StateChangeReturn continue_state (StateChangeReturn ret)
 Commit the state change of the element and proceed to the next pending state if any. More...

 
void lost_state ()
 Brings the element to the lost state. More...

 
bool sync_state_with_parent ()
 Tries to change the state of the element to the same as its parent. More...

 
StateChangeReturn change_state (StateChange transition)
 Perform transition on element. More...

 
void post_message (int code, int line, MessageType type=Gst::MESSAGE_INFO, const Glib::QueryQuark& domain=get_core_error_quark(), const Glib::ustring& text=Glib::ustring(), const Glib::ustring& debug=Glib::ustring(), const Glib::ustring& file=Glib::ustring(), const Glib::ustring& function=Glib::ustring())
 Post an error, warning or info message on the bus from inside an element. More...

 
bool post_message (const Glib::RefPtr< Gst::Message >& message)
 Post a message on the element's Gst::Bus. More...

 
bool query (const Glib::RefPtr< Gst::Query >& query) const
 Performs a query on the given element. More...

 
bool query_convert (Gst::Format src_format, gint64 src_val, Format dest_format, gint64& dest_val) const
 Queries an element to convert src_val in src_format to dest_format. More...

 
bool query_position (Gst::Format format, gint64& cur) const
 Queries an element (usually top-level pipeline or playbin element) for the stream position in nanoseconds. More...

 
bool query_position (Gst::Format format) const
 Queries an element for the stream position. More...

 
bool query_duration (Gst::Format format, gint64& duration) const
 Queries an element (usually top-level pipeline or playbin element) for the total stream duration in nanoseconds. More...

 
bool query_duration (Gst::Format format) const
 Queries an element for the total stream duration. More...

 
bool seek (Format format, SeekFlags seek_flags, gint64 seek_pos)
 Simple API to perform a seek on the given element, meaning it just seeks to the given position relative to the start of the stream. More...

 
bool seek (double rate, Format format, SeekFlags flags, SeekType cur_type, gint64 cur, SeekType stop_type, gint64 stop)
 Sends a seek event to an element. More...

 
bool send_event (const Glib::RefPtr< Gst::Event >& event)
 Sends an event to an element. More...

 
Glib::SignalProxy0< void > signal_no_more_pads ()
 
Glib::SignalProxy1< void,

const Glib::RefPtr< Gst::Pad >& > 
signal_pad_added ()
 
Glib::SignalProxy1< void,

const Glib::RefPtr< Gst::Pad >& > 
signal_pad_removed ()
 
virtual void release_pad_vfunc (const Glib::RefPtr< Gst::Pad >& pad)
 Called when a request pad is to be released. More...

 
virtual Glib::RefPtr< Gst::Padrequest_new_pad_vfunc (Glib::RefPtr< Gst::PadTemplate > templ, const Glib::ustring& name, const Glib::RefPtr< const Gst::Caps >& caps)
 Called when a new pad is requested. More...

 
virtual StateChangeReturn get_state_vfunc (State& state, State& pending, ClockTime timeout) const
 Get the state of the element. More...

 
virtual StateChangeReturn set_state_vfunc (State state)
 Set a new state on the element. More...

 
virtual StateChangeReturn change_state_vfunc (StateChange transition)
 Called by set_state to perform an incremental state change. More...

 
virtual void set_bus_vfunc (const Glib::RefPtr< Gst::Bus >& bus)
 Set a Gst::Bus on the element. More...

 
virtual Glib::RefPtr< Gst::Clockprovide_clock_vfunc ()
 Gets the Gst::Clock provided by the element. More...

 
virtual bool set_clock_vfunc (const Glib::RefPtr< Gst::Clock >& clock)
 Set the Gst::Clock on the element. More...

 
virtual bool send_event_vfunc (const Glib::RefPtr< Gst::Event >& event)
 Send a Gst::Event to the element. More...

 
virtual bool query_vfunc (const Glib::RefPtr< Gst::Query >&query) const
 Perform a Gst::Query on the element. More...

 
virtual void set_context_vfunc (const Glib::RefPtr< Gst::Context >& context)
 Set a Gst::Context on the element. More...

 
Glib::RefPtr< Gst::PadTemplateget_pad_template (const Glib::ustring& factory_name) const
 
template<typename T >
Glib::RefPtr< Gst::Elementproperty (const Glib::ustring& name, const T& value)
 Sets specified property. 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 Public Member Functions inherited from Gst::Element
static GType get_type ()
 Get the GType for this class, for use with the underlying GObject type system. More...

 
- 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...

 

Static Public Attributes

static const Glib::ustring SINK_NAME
 The name of the templates for the sink pad ("sink"). More...

 
static const Glib::ustring SRC_NAME
 The name of the templates for the source pad ("src"). More...

 

Related Functions

(Note that these are not member functions.)

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

 

Additional Inherited Members

- Protected Member Functions inherited from Gst::Element
virtual void on_no_more_pads ()
 This is a default handler for the signal signal_no_more_pads(). More...

 
virtual void on_pad_added (const Glib::RefPtr< Gst::Pad >& new_pad)
 This is a default handler for the signal signal_pad_added(). More...

 
virtual void on_pad_removed (const Glib::RefPtr< Gst::Pad >& old_pad)
 This is a default handler for the signal signal_pad_removed(). 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...

 

Detailed Description

A base class for simple transform filters.

This base class is for filter elements that process data.

It provides for:

  • one sinkpad and one srcpad
  • Possible formats on sink and source pad implemented with custom transform_caps_vfunc() function. By default uses same format on sink and source.
  • Handles state changes.
  • Does flushing.
  • Push mode.
  • Pull mode if the sub-class transform_vfunc() can operate on arbitrary data.

Use Cases:

  • 1. Passthrough mode
    • Element has no interest in modifying the buffer. It may want to inspect it, in which case the element should have a transform_ip_vfunc() function. If there is no transform_ip_vfunc() function in passthrough mode, the buffer is pushed intact.
    • On the GstBaseTransformClass is the passthrough_on_same_caps variable which will automatically set/unset passthrough based on whether the element negotiates the same caps on both pads.
    • passthrough_on_same_caps on an element that doesn't implement a transform_caps_vfunc() function is useful for elements that only inspect data (such as level).
    Example elements
  • 2. Modifications in-place - input buffer and output buffer are the same thing. Example elements
    • Volume.
    • AudioConvert in certain modes (signed/unsigned conversion).
    • FfmpegColorSpace in certain modes (endianness swapping).
  • 3. Modifications only to the caps/metadata of a buffer
    • The element does not require writable data, but non-writable buffers should be subbuffered so that the meta-information can be replaced.
    • Elements wishing to operate in this mode should replace the prepare_output_buffer_vfunc() method to create subbuffers of the input buffer and set always_in_place to TRUE.
    Example elements
    • CapsFilter when setting caps on outgoing buffers that have none.
    • Identity when it is going to re-timestamp buffers by datarate.
  • 4. Normal mode Example elements
  • 5. Special output buffer allocations
    • Elements which need to do special allocation of their output buffers other than what Gst::Pad::alloc_buffer() allows should implement a prepare_output_buffer_vfunc() method, which calls the parent implementation and passes the newly allocated buffer.
    Example elements
    • Efence.

Sub-class settable flags on Gst::BaseTransform

- <B>passthrough</B>
      - Implies that in the current configuration, the sub-class is not
      interested in modifying the buffers.
      - Elements which are always in passthrough mode whenever the same
      caps has been negotiated on both pads can set the class variable
      passthrough_on_same_caps to have this behaviour automatically.
      .
- <B>always_in_place</B>
      - Determines whether a non-writable buffer will be copied before
      passing to the transform_ip function.
      - Implied TRUE if no transform function is implemented.
      - Implied FALSE if ONLY transform function is implemented.

Constructor & Destructor Documentation

virtual Gst::BaseTransform::~BaseTransform ( )
virtual

Member Function Documentation

virtual bool Gst::BaseTransform::accept_caps_vfunc ( PadDirection  direction,
const Glib::RefPtr< const Gst::Caps >&  caps 
)
virtual

Optional.

Since 0.10.30 Subclasses can override this method to check if the caps can be handled by the element. The default implementation might not be the most optimal way to check this in all cases.

virtual void Gst::BaseTransform::before_transform_vfunc ( const Glib::RefPtr< Gst::Buffer >&  buffer)
virtual

Optional.

Since 0.10.22 This method is called right before the base class will start processing. Dynamic properties or other delayed configuration could be performed in this method.

virtual Glib::RefPtr<Gst::Caps> Gst::BaseTransform::fixate_caps_vfunc ( PadDirection  direction,
const Glib::RefPtr< Gst::Caps >&  caps,
const Glib::RefPtr< Gst::Caps >&  othercaps 
)
virtual

Optional.

Given the pad in this direction and the given caps, fixate the caps on the other pad.

Glib::RefPtr<Gst::Pad> Gst::BaseTransform::get_sink_pad ( )

Gives the refptr to the sink Gst::Pad object of the element.

Glib::RefPtr<const Gst::Pad> Gst::BaseTransform::get_sink_pad ( ) const
Glib::RefPtr<Gst::Pad> Gst::BaseTransform::get_src_pad ( )

Gives the refptr to the source Gst::Pad object of the element.

Glib::RefPtr<const Gst::Pad> Gst::BaseTransform::get_src_pad ( ) const
static GType Gst::BaseTransform::get_type ( )
static

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

virtual bool Gst::BaseTransform::get_unit_size_vfunc ( const Glib::RefPtr< Gst::Caps >&  caps,
gsize &  size 
) const
virtual

Optional.

Given the size of a buffer in the given direction with the given caps, calculate the size in bytes of a buffer on the other pad with the given other caps. The default implementation uses get_unit_size_vfunc() and keeps the number of units the same. Required if the transform is not in-place. Get the size in bytes of one unit for the given caps.

GstBaseTransform* Gst::BaseTransform::gobj ( )
inline

Provides access to the underlying C GObject.

const GstBaseTransform* Gst::BaseTransform::gobj ( ) const
inline

Provides access to the underlying C GObject.

GstBaseTransform* Gst::BaseTransform::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::BaseTransform::is_in_place ( ) const

See if trans is configured as a in_place transform.

Returns
true is the transform is configured in in_place mode.

MT safe.

bool Gst::BaseTransform::is_passthrough ( ) const

See if trans is configured as a passthrough transform.

Returns
true is the transform is configured in passthrough mode.

MT safe.

bool Gst::BaseTransform::is_qos_enabled ( ) const

Queries if the transform will handle QoS.

Returns
true if QoS is enabled.

MT safe.

virtual FlowReturn Gst::BaseTransform::prepare_output_buffer_vfunc ( const Glib::RefPtr< Gst::Buffer >&  input,
Glib::RefPtr< Gst::Buffer >&  buffer 
)
virtual

Optional.

Subclasses can override this to do their own allocation of output buffers. Elements that only do analysis can return a subbuffer or even just increment the reference to the input buffer (if in passthrough mode).

Glib::PropertyProxy< bool > Gst::BaseTransform::property_qos ( )

Handle Quality-of-Service events.

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< bool > Gst::BaseTransform::property_qos ( ) const

Handle Quality-of-Service events.

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.
virtual bool Gst::BaseTransform::set_caps_vfunc ( const Glib::RefPtr< Gst::Caps >&  incaps,
const Glib::RefPtr< Gst::Caps >&  outcaps 
)
virtual

Allows the subclass to be notified of the actual caps set.

void Gst::BaseTransform::set_gap_aware ( bool  gap_aware)

If gap_aware is false (the default), output buffers will have the Gst::BUFFER_FLAG_GAP flag unset.

If set to true, the element must handle output buffers with this flag set correctly, i.e. it can assume that the buffer contains neutral data but must unset the flag if the output is no neutral data.

MT safe.

Parameters
gap_awareNew state.
void Gst::BaseTransform::set_in_place ( bool  in_place)

Determines whether a non-writable buffer will be copied before passing to the transform_ip function.

  • Always true if no transform function is implemented.
  • Always false if ONLY transform function is implemented.

MT safe.

Parameters
in_placeBoolean value indicating that we would like to operate on in_place buffers.
void Gst::BaseTransform::set_passthrough ( bool  passthrough)

Set passthrough mode for this filter by default.

This is mostly useful for filters that do not care about negotiation.

Always true for filters which don't implement either a transform or transform_ip method.

MT safe.

Parameters
passthroughBoolean indicating passthrough mode.
void Gst::BaseTransform::set_qos_enabled ( bool  enabled)

Enable or disable QoS handling in the transform.

MT safe.

Parameters
enabledNew state.
virtual bool Gst::BaseTransform::src_event_vfunc ( const Glib::RefPtr< Gst::Event >&  event)
virtual

Optional.

Event handler on the source pad.

virtual bool Gst::BaseTransform::start_vfunc ( )
virtual

Optional.

Called when the element starts processing. Allows opening external resources.

virtual bool Gst::BaseTransform::stop_vfunc ( )
virtual

Optional.

Called when the element starts processing. Allows opening external resources.

virtual Glib::RefPtr<Gst::Caps> Gst::BaseTransform::transform_caps_vfunc ( PadDirection  direction,
const Glib::RefPtr< Gst::Caps >&  caps,
const Glib::RefPtr< Gst::Caps >&  filter 
)
virtual

Optional.

Given the pad in this direction and the given caps, what caps are allowed on the other pad in this element ?

virtual FlowReturn Gst::BaseTransform::transform_ip_vfunc ( const Glib::RefPtr< Gst::Buffer >&  buf)
virtual

Required if the element operates in-place.

Transform the incoming buffer in-place.

virtual FlowReturn Gst::BaseTransform::transform_vfunc ( const Glib::RefPtr< Gst::Buffer >&  inbuf,
const Glib::RefPtr< Gst::Buffer >&  outbuf 
)
virtual

Required if the element does not operate in-place.

Transforms one incoming buffer to one outgoing buffer. The function is allowed to change size/timestamp/duration of the outgoing buffer.

void Gst::BaseTransform::update_qos ( double  proportion,
ClockTimeDiff  diff,
ClockTime  timestamp 
)

Set the QoS parameters in the transform.

This function is called internally when a QOS event is received but subclasses can provide custom information when needed.

MT safe.

Parameters
proportionThe proportion.
diffThe diff against the clock.
timestampThe timestamp of the buffer generating the QoS expressed in running_time.

Friends And Related Function Documentation

Glib::RefPtr< Gst::BaseTransform > wrap ( GstBaseTransform *  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.

Member Data Documentation

const Glib::ustring Gst::BaseTransform::SINK_NAME
static

The name of the templates for the sink pad ("sink").

const Glib::ustring Gst::BaseTransform::SRC_NAME
static

The name of the templates for the source pad ("src").


The documentation for this class was generated from the following file:
  • gstreamermm/basetransform.h