gstreamermm: Gst::BaseSink Class Reference

The base class for sink elements. More...

Inheritance diagram for Gst::BaseSink:
Collaboration diagram for Gst::BaseSink:

Public Member Functions

virtual ~BaseSink ()
 
GstBaseSink* gobj ()
 Provides access to the underlying C GObject. More...

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

 
GstBaseSink* 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 query_latency (bool& live, bool& upstream_live, ClockTime& min_latency, ClockTime& max_latency) const
 Query the sink for the latency parameters. More...

 
ClockTime get_latency () const
 Get the currently configured latency. More...

 
Gst::FlowReturn do_preroll (const Glib::RefPtr< Gst::MiniObject >& obj)
 If the sink spawns its own thread for pulling buffers from upstream it should call this method after it has pulled a buffer. More...

 
FlowReturn wait_preroll ()
 If the Gst::BaseSinkClass.render() method performs its own synchronisation against the clock it must unblock when going from PLAYING to the PAUSED state and call this method before continuing to render the remaining data. More...

 
ClockReturn wait_clock (ClockTime time, ClockTimeDiff& jitter)
 This function will block until time is reached. More...

 
FlowReturn wait (ClockTime time, ClockTimeDiff& jitter)
 This function will wait for preroll to complete and will then block until time is reached. More...

 
ClockReturn wait_clock (ClockTime time)
 This function will block until time is reached. More...

 
FlowReturn wait (ClockTime time)
 This function will block until time is reached. More...

 
void set_sync (bool sync)
 Configures sink to synchronize on the clock or not. More...

 
bool get_sync () const
 Checks if sink is currently configured to synchronize against the clock. More...

 
void set_max_lateness (gint64 max_lateness)
 Sets the new max lateness value to max_lateness. More...

 
gint64 get_max_lateness () const
 Gets the max lateness value. More...

 
void set_qos_enabled (bool enabled)
 Configures sink to send Quality-of-Service events upstream. More...

 
bool is_qos_enabled () const
 Checks if sink is currently configured to send Quality-of-Service events upstream. More...

 
void set_async_enabled (bool enabled)
 Configures sink to perform all state changes asynchronusly. More...

 
bool is_async_enabled () const
 Checks if sink is currently configured to perform asynchronous state changes to PAUSED. More...

 
void set_ts_offset (ClockTimeDiff offset)
 Adjust the synchronisation of sink with offset. More...

 
ClockTimeDiff get_ts_offset () const
 Get the synchronisation offset of sink. More...

 
void set_render_delay (ClockTime delay)
 Set the render delay in sink to delay. More...

 
ClockTime get_render_delay () const
 Get the render delay of sink. More...

 
void set_blocksize (guint blocksize)
 Set the number of bytes that the sink will pull when it is operating in pull mode. More...

 
guint get_blocksize () const
 Get the number of bytes that the sink will pull when it is operating in pull mode. More...

 
guint64 get_throttle_time () const
 Get the time that will be inserted between frames to control the maximum buffers per second. More...

 
void set_throttle_time (guint64 throttle)
 Set the time that will be inserted between rendered buffers. More...

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

 
Glib::RefPtr< const Gst::Padget_sink_pad () const
 
Glib::PropertyProxy< bool > property_async ()
 Go asynchronously to PAUSED. More...

 
Glib::PropertyProxy_ReadOnly

< bool > 
property_async () const
 Go asynchronously to PAUSED. More...

 
Glib::PropertyProxy< gint64 > property_max_lateness ()
 Maximum number of nanoseconds that a buffer can be late before it is dropped (-1 unlimited). More...

 
Glib::PropertyProxy_ReadOnly

< gint64 > 
property_max_lateness () const
 Maximum number of nanoseconds that a buffer can be late before it is dropped (-1 unlimited). More...

 
Glib::PropertyProxy< bool > property_qos ()
 Generate Quality-of-Service events upstream. More...

 
Glib::PropertyProxy_ReadOnly

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

 
Glib::PropertyProxy< bool > property_sync ()
 Sync on the clock. More...

 
Glib::PropertyProxy_ReadOnly

< bool > 
property_sync () const
 Sync on the clock. More...

 
Glib::PropertyProxy< gint64 > property_ts_offset ()
 Timestamp offset in nanoseconds. More...

 
Glib::PropertyProxy_ReadOnly

< gint64 > 
property_ts_offset () const
 Timestamp offset in nanoseconds. More...

 
Glib::PropertyProxy< guint64 > property_render_delay ()
 Additional render delay of the sink in nanoseconds. More...

 
Glib::PropertyProxy_ReadOnly

< guint64 > 
property_render_delay () const
 Additional render delay of the sink in nanoseconds. More...

 
Glib::PropertyProxy< guint64 > property_throttle_time ()
 The time to keep between rendered buffers (0 = disabled). More...

 
Glib::PropertyProxy_ReadOnly

< guint64 > 
property_throttle_time () const
 The time to keep between rendered buffers (0 = disabled). More...

 
Glib::PropertyProxy< guint > property_blocksize ()
 Size in bytes to pull per buffer (0 = default). More...

 
Glib::PropertyProxy_ReadOnly

< guint > 
property_blocksize () const
 Size in bytes to pull per buffer (0 = default). More...

 
virtual Glib::RefPtr< Gst::Capsget_caps_vfunc (Glib::RefPtr< Gst::Caps > caps) const
 Called to get sink pad caps from the subclass. More...

 
virtual bool set_caps_vfunc (const Glib::RefPtr< Gst::Caps >& caps)
 Notify subclass of changed caps. More...

 
virtual void get_times_vfunc (const Glib::RefPtr< Gst::Buffer >& buffer, ClockTime& start, ClockTime&end) const
 Called to get the start and end times for synchronising the passed buffer to the clock. More...

 
virtual bool start_vfunc ()
 Start processing. More...

 
virtual bool stop_vfunc ()
 Stop processing. More...

 
virtual bool unlock_vfunc ()
 Unlock any pending access to the resource. More...

 
virtual bool event_vfunc (const Glib::RefPtr< Gst::Event >& event)
 Override this to handle events arriving on the sink pad. More...

 
virtual FlowReturn preroll_vfunc (const Glib::RefPtr< Gst::Buffer >& buffer)
 Called to present the preroll buffer if desired. More...

 
virtual FlowReturn render_vfunc (const Glib::RefPtr< Gst::Buffer >& buffer)
 Called when a buffer should be presented or output, at the correct moment if the Gst::BaseSink has been set to sync to the clock. More...

 
virtual bool activate_pull_vfunc (bool active)
 Subclasses should override this when they need to perform special processing when changing to the PLAYING state asynchronously. More...

 
virtual Glib::RefPtr< Gst::Capsfixate_vfunc (const Glib::RefPtr< Gst::Caps >& caps)
 Only useful in pull mode, this vmethod will be called in response to Gst::Pad::fixate_caps() being called on the sink pad. More...

 
virtual bool unlock_stop_vfunc ()
 Clear the previous unlock request. More...

 
virtual FlowReturn render_list_vfunc (const Glib::RefPtr< Gst::BufferList >& buffer_list)
 Render a BufferList. 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...

 

Related Functions

(Note that these are not member functions.)

Glib::RefPtr< Gst::BaseSinkwrap (GstBaseSink* 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

The base class for sink elements.

Gst::BaseSink is the base class for sink elements in GStreamer, such as xvimagesink or filesink. It is a layer on top of Gst::Element that provides a simplified interface to plugin writers. Gst::BaseSink handles many details for you, for example: preroll, clock synchronization, state changes, activation in push or pull mode, and queries.

In most cases, when writing sink elements, there is no need to implement class methods from Gst::Element or to set functions on pads, because the Gst::BaseSink infrastructure should be sufficient.

TODO: correct paragraph below for C++ and include example from C API:

Gst::BaseSink provides support for exactly one sink pad, which should be named "sink". A sink implementation (subclass of Gst::BaseSink) should install a pad template in its base_init function, like so:

Gst::BaseSink will handle the prerolling correctly. This means that it will return Gst::STATE_CHANGE_ASYNC from a state change to PAUSED until the first buffer arrives in this element. The base class will call the Gst::BaseSink::preroll_vfunc() vmethod with this preroll buffer and will then commit the state change to the next asynchronously pending state.

When the element is set to PLAYING, Gst::BaseSink will synchronise on the clock using the times returned from get_times_vfunc(). If this function returns Gst::CLOCK_TIME_NONE for the start time, no synchronisation will be done. Synchronisation can be disabled entirely by setting the object "sync" property to FALSE.

After synchronisation the virtual method Gst::BaseSink::render_vfunc() will be called. Subclasses should minimally implement this method.

Since GStreamer 0.10.3 subclasses that synchronise on the clock in the render_vfunc() vmethod are supported as well. These classes typically receive a buffer in the render method and can then potentially block on the clock while rendering. A typical example is an audiosink. Since GStreamer 0.10.11 these subclasses can use wait_preroll() to perform the blocking wait.

Upon receiving the EOS event in the PLAYING state, Gst::BaseSink will wait for the clock to reach the time indicated by the stop time of the last get_times_vfunc() call before posting an EOS message. When the element receives EOS in PAUSED, preroll completes, the event is queued and an EOS message is posted when going to PLAYING.

Gst::BaseSink will internally use the Gst::EVENT_NEWSEGMENT events to schedule synchronisation and clipping of buffers. Buffers that fall completely outside of the current segment are dropped. Buffers that fall partially in the segment are rendered (and prerolled). Subclasses should do any subbuffer clipping themselves when needed.

Gst::BaseSink will by default report the current playback position in Gst::FORMAT_TIME based on the current clock time and segment information. If no clock has been set on the element, the query will be forwarded upstream.

The set_caps_vfunc() function will be called when the subclass should configure itself to process a specific media type.

The start_vfunc() and stop_vfunc() virtual methods will be called when resources should be allocated. Any preroll_vfunc(), render_vfunc() and set_caps_vfunc() function will be called between the start_vfunc() and stop_vfunc() calls.

The event_vfunc() virtual method will be called when an event is received by Gst::BaseSink. Normally this method should only be overriden by very specific elements (such as file sinks) which need to handle the newsegment event specially. The unlock_vfunc() method is called when the elements should unblock any blocking operations they perform in the render_vfunc() method. This is mostly useful when the render_vfunc() method performs a blocking write on a file descriptor, for example.

The max-lateness property affects how the sink deals with buffers that arrive too late in the sink. A buffer arrives too late in the sink when the presentation time (as a combination of the last segment, buffer timestamp and element base_time) plus the duration is before the current time of the clock. If the frame is later than max-lateness, the sink will drop the buffer without calling the render method. This feature is disabled if sync is disabled, the get_times_vfunc() method does not return a valid start time or max-lateness is set to -1 (the default). Subclasses can use set_max_lateness() to configure the max-lateness value.

The qos property will enable the quality-of-service features of the basesink which gather statistics about the real-time performance of the clock synchronisation. For each buffer received in the sink, statistics are gathered and a QOS event is sent upstream with these numbers. This information can then be used by upstream elements to reduce their processing rate, for example.

Since GStreamer 0.10.15 the async property can be used to instruct the sink to never perform an ASYNC state change. This feature is mostly usable when dealing with non-synchronized streams or sparse streams.

Last reviewed on 2007-08-29 (0.10.15)

Constructor & Destructor Documentation

virtual Gst::BaseSink::~BaseSink ( )
virtual

Member Function Documentation

virtual bool Gst::BaseSink::activate_pull_vfunc ( bool  active)
virtual

Subclasses should override this when they need to perform special processing when changing to the PLAYING state asynchronously.

Called with the OBJECT_LOCK held. Subclasses should override this when they can provide an alternate method of spawning a thread to drive the pipeline in pull mode. Should start or stop the pulling thread, depending on the value of the "active" argument. Called after actually activating the sink pad in pull mode. The default implementation starts a task on the sink pad.

Gst::FlowReturn Gst::BaseSink::do_preroll ( const Glib::RefPtr< Gst::MiniObject >&  obj)

If the sink spawns its own thread for pulling buffers from upstream it should call this method after it has pulled a buffer.

If the element needed to preroll, this function will perform the preroll and will then block until the element state is changed.

This function should be called with the PREROLL_LOCK held.

Parameters
objThe mini object that caused the preroll.
Returns
Gst::FLOW_OK if the preroll completed and processing can continue. Any other return value should be returned from the render vmethod.
virtual bool Gst::BaseSink::event_vfunc ( const Glib::RefPtr< Gst::Event >&  event)
virtual

Override this to handle events arriving on the sink pad.

virtual Glib::RefPtr<Gst::Caps> Gst::BaseSink::fixate_vfunc ( const Glib::RefPtr< Gst::Caps >&  caps)
virtual

Only useful in pull mode, this vmethod will be called in response to Gst::Pad::fixate_caps() being called on the sink pad.

Implement if you have ideas about what should be the default values for the caps you support.

guint Gst::BaseSink::get_blocksize ( ) const

Get the number of bytes that the sink will pull when it is operating in pull mode.

Returns
The number of bytes sink will pull in pull mode.
virtual Glib::RefPtr<Gst::Caps> Gst::BaseSink::get_caps_vfunc ( Glib::RefPtr< Gst::Caps caps) const
virtual

Called to get sink pad caps from the subclass.

ClockTime Gst::BaseSink::get_latency ( ) const

Get the currently configured latency.

Returns
The configured latency.
gint64 Gst::BaseSink::get_max_lateness ( ) const

Gets the max lateness value.

See gst_base_sink_set_max_lateness for more details.

Returns
The maximum time in nanoseconds that a buffer can be late before it is dropped and not rendered. A value of -1 means an unlimited time.
ClockTime Gst::BaseSink::get_render_delay ( ) const

Get the render delay of sink.

see set_render_delay() for more information about the render delay.

Returns
The render delay of sink.
Glib::RefPtr<Gst::Pad> Gst::BaseSink::get_sink_pad ( )

Gets the sink Gst::Pad object of the element.

Glib::RefPtr<const Gst::Pad> Gst::BaseSink::get_sink_pad ( ) const
bool Gst::BaseSink::get_sync ( ) const

Checks if sink is currently configured to synchronize against the clock.

Returns
true if the sink is configured to synchronize against the clock.
guint64 Gst::BaseSink::get_throttle_time ( ) const

Get the time that will be inserted between frames to control the maximum buffers per second.

Returns
The number of nanoseconds sink will put between frames.
virtual void Gst::BaseSink::get_times_vfunc ( const Glib::RefPtr< Gst::Buffer >&  buffer,
ClockTime start,
ClockTime end 
) const
virtual

Called to get the start and end times for synchronising the passed buffer to the clock.

ClockTimeDiff Gst::BaseSink::get_ts_offset ( ) const

Get the synchronisation offset of sink.

Returns
The synchronisation offset.
static GType Gst::BaseSink::get_type ( )
static

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

GstBaseSink* Gst::BaseSink::gobj ( )
inline

Provides access to the underlying C GObject.

const GstBaseSink* Gst::BaseSink::gobj ( ) const
inline

Provides access to the underlying C GObject.

GstBaseSink* Gst::BaseSink::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::BaseSink::is_async_enabled ( ) const

Checks if sink is currently configured to perform asynchronous state changes to PAUSED.

Returns
true if the sink is configured to perform asynchronous state changes.
bool Gst::BaseSink::is_qos_enabled ( ) const

Checks if sink is currently configured to send Quality-of-Service events upstream.

Returns
true if the sink is configured to perform Quality-of-Service.
virtual FlowReturn Gst::BaseSink::preroll_vfunc ( const Glib::RefPtr< Gst::Buffer >&  buffer)
virtual

Called to present the preroll buffer if desired.

Glib::PropertyProxy< bool > Gst::BaseSink::property_async ( )

Go asynchronously to PAUSED.

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::BaseSink::property_async ( ) const

Go asynchronously to PAUSED.

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< guint > Gst::BaseSink::property_blocksize ( )

Size in bytes to pull per buffer (0 = default).

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< guint > Gst::BaseSink::property_blocksize ( ) const

Size in bytes to pull per buffer (0 = default).

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< gint64 > Gst::BaseSink::property_max_lateness ( )

Maximum number of nanoseconds that a buffer can be late before it is dropped (-1 unlimited).

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< gint64 > Gst::BaseSink::property_max_lateness ( ) const

Maximum number of nanoseconds that a buffer can be late before it is dropped (-1 unlimited).

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< bool > Gst::BaseSink::property_qos ( )

Generate Quality-of-Service events upstream.

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::BaseSink::property_qos ( ) const

Generate Quality-of-Service events upstream.

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< guint64 > Gst::BaseSink::property_render_delay ( )

Additional render delay of the sink in nanoseconds.

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< guint64 > Gst::BaseSink::property_render_delay ( ) const

Additional render delay of the sink in nanoseconds.

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< bool > Gst::BaseSink::property_sync ( )

Sync on the clock.

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::BaseSink::property_sync ( ) const

Sync on the clock.

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< guint64 > Gst::BaseSink::property_throttle_time ( )

The time to keep between rendered buffers (0 = disabled).

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< guint64 > Gst::BaseSink::property_throttle_time ( ) const

The time to keep between rendered buffers (0 = disabled).

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< gint64 > Gst::BaseSink::property_ts_offset ( )

Timestamp offset in nanoseconds.

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< gint64 > Gst::BaseSink::property_ts_offset ( ) const

Timestamp offset in nanoseconds.

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::BaseSink::query_latency ( bool &  live,
bool &  upstream_live,
ClockTime min_latency,
ClockTime max_latency 
) const

Query the sink for the latency parameters.

The latency will be queried from the upstream elements. live will be true if sink is configured to synchronize against the clock. upstream_live will be true if an upstream element is live.

If both live and upstream_live are true, the sink will want to compensate for the latency introduced by the upstream elements by setting the min_latency to a strictly possitive value.

This function is mostly used by subclasses.

Parameters
liveIf the sink is live.
upstream_liveIf an upstream element is live.
min_latencyThe min latency of the upstream elements.
max_latencyThe max latency of the upstream elements.
Returns
true if the query succeeded.
virtual FlowReturn Gst::BaseSink::render_list_vfunc ( const Glib::RefPtr< Gst::BufferList >&  buffer_list)
virtual

Render a BufferList.

virtual FlowReturn Gst::BaseSink::render_vfunc ( const Glib::RefPtr< Gst::Buffer >&  buffer)
virtual

Called when a buffer should be presented or output, at the correct moment if the Gst::BaseSink has been set to sync to the clock.

void Gst::BaseSink::set_async_enabled ( bool  enabled)

Configures sink to perform all state changes asynchronusly.

When async is disabled, the sink will immediately go to PAUSED instead of waiting for a preroll buffer. This feature is useful if the sink does not synchronize against the clock or when it is dealing with sparse streams.

Parameters
enabledThe new async value.
void Gst::BaseSink::set_blocksize ( guint  blocksize)

Set the number of bytes that the sink will pull when it is operating in pull mode.

Parameters
blocksizeThe blocksize in bytes.
virtual bool Gst::BaseSink::set_caps_vfunc ( const Glib::RefPtr< Gst::Caps >&  caps)
virtual

Notify subclass of changed caps.

void Gst::BaseSink::set_max_lateness ( gint64  max_lateness)

Sets the new max lateness value to max_lateness.

This value is used to decide if a buffer should be dropped or not based on the buffer timestamp and the current clock time. A value of -1 means an unlimited time.

Parameters
max_latenessThe new max lateness value.
void Gst::BaseSink::set_qos_enabled ( bool  enabled)

Configures sink to send Quality-of-Service events upstream.

Parameters
enabledThe new qos value.
void Gst::BaseSink::set_render_delay ( ClockTime  delay)

Set the render delay in sink to delay.

The render delay is the time between actual rendering of a buffer and its synchronisation time. Some devices might delay media rendering which can be compensated for with this function.

After calling this function, this sink will report additional latency and other sinks will adjust their latency to delay the rendering of their media.

This function is usually called by subclasses.

Parameters
delayThe new delay.
void Gst::BaseSink::set_sync ( bool  sync)

Configures sink to synchronize on the clock or not.

When sync is false, incoming samples will be played as fast as possible. If sync is true, the timestamps of the incomming buffers will be used to schedule the exact render time of its contents.

Parameters
syncThe new sync value.
void Gst::BaseSink::set_throttle_time ( guint64  throttle)

Set the time that will be inserted between rendered buffers.

This can be used to control the maximum buffers per second that the sink will render.

Parameters
throttleThe throttle time in nanoseconds.
void Gst::BaseSink::set_ts_offset ( ClockTimeDiff  offset)

Adjust the synchronisation of sink with offset.

A negative value will render buffers earlier than their timestamp. A positive value will delay rendering. This function can be used to fix playback of badly timestamped buffers.

Parameters
offsetThe new offset.
virtual bool Gst::BaseSink::start_vfunc ( )
virtual

Start processing.

Ideal for opening resources in the subclass.

virtual bool Gst::BaseSink::stop_vfunc ( )
virtual

Stop processing.

Subclasses should use this to close resources.

virtual bool Gst::BaseSink::unlock_stop_vfunc ( )
virtual

Clear the previous unlock request.

Subclasses should clear any state they set during unlock_vfunc(), such as clearing command queues.

virtual bool Gst::BaseSink::unlock_vfunc ( )
virtual

Unlock any pending access to the resource.

Subclasses should unblock any blocked function ASAP.

FlowReturn Gst::BaseSink::wait ( ClockTime  time,
ClockTimeDiff jitter 
)

This function will wait for preroll to complete and will then block until time is reached.

It is usually called by subclasses that use their own internal synchronisation but want to let some synchronization (like EOS) be handled by the base class.

This function should only be called with the PREROLL_LOCK held (like when receiving an EOS event in the signal_event() vmethod or when handling buffers in signal_render()).

The time argument should be the running_time of when the timeout should happen and will be adjusted with any latency and offset configured in the sink.

Parameters
timeThe running_time to be reached.
jitterThe jitter to be filled with time diff, or 0.
Returns
Gst::FlowReturn.
FlowReturn Gst::BaseSink::wait ( ClockTime  time)

This function will block until time is reached.

It is usually called by subclasses that use their own internal synchronisation but want to let the EOS be handled by the base class.

This function should only be called with the PREROLL_LOCK held, like when receiving an EOS event in the event vmethod.

The time argument should be the running_time of when the EOS should happen and will be adjusted with any latency and offset configured in the sink.

Since 0.10.15.

Parameters
timeThe running time to be reached.
Returns
Gst::FlowReturn.
ClockReturn Gst::BaseSink::wait_clock ( ClockTime  time,
ClockTimeDiff jitter 
)

This function will block until time is reached.

It is usually called by subclasses that use their own internal synchronisation.

If time is not valid, no sycnhronisation is done and Gst::CLOCK_BADTIME is returned. Likewise, if synchronisation is disabled in the element or there is no clock, no synchronisation is done and Gst::CLOCK_BADTIME is returned.

This function should only be called with the PREROLL_LOCK held, like when receiving an EOS event in the Gst::BaseSinkClass.event() vmethod or when receiving a buffer in the Gst::BaseSinkClass.render() vmethod.

The time argument should be the running_time of when this method should return and is not adjusted with any latency or offset configured in the sink.

Parameters
timeThe running_time to be reached.
jitterThe jitter to be filled with time diff, or 0.
Returns
Gst::ClockReturn.
ClockReturn Gst::BaseSink::wait_clock ( ClockTime  time)

This function will block until time is reached.

It is usually called by subclasses that use their own internal synchronisation.

If time is not valid, no sycnhronisation is done and Gst::CLOCK_BADTIME is returned. Likewise, if synchronisation is disabled in the element or there is no clock, no synchronisation is done and Gst::CLOCK_BADTIME is returned.

This function should only be called with the PREROLL_LOCK held, like when receiving an EOS event in the event vmethod or when receiving a buffer in the render vmethod.

The time argument should be the running_time of when this method should return and is not adjusted with any latency or offset configured in the sink.

Since 0.10.20.

Parameters
timeThe running_time to be reached.
Returns
Gst::ClockReturn.
FlowReturn Gst::BaseSink::wait_preroll ( )

If the Gst::BaseSinkClass.render() method performs its own synchronisation against the clock it must unblock when going from PLAYING to the PAUSED state and call this method before continuing to render the remaining data.

This function will block until a state change to PLAYING happens (in which case this function returns Gst::FLOW_OK) or the processing must be stopped due to a state change to READY or a FLUSH event (in which case this function returns Gst::FLOW_FLUSHING).

This function should only be called with the PREROLL_LOCK held, like in the render function.

Returns
Gst::FLOW_OK if the preroll completed and processing can continue. Any other return value should be returned from the render vmethod.

Friends And Related Function Documentation

Glib::RefPtr< Gst::BaseSink > wrap ( GstBaseSink *  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:
  • gstreamermm/basesink.h