Struct gstreamer_base::BaseSink [−][src]
pub struct BaseSink(_);
Expand description
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. 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
BaseSink infrastructure should be sufficient.
BaseSink provides support for exactly one sink pad, which should be
named “sink”. A sink implementation (subclass of BaseSink) should
install a pad template in its class_init function, like so:
static void
my_element_class_init (GstMyElementClass *klass)
{
GstElementClass *gstelement_class = GST_ELEMENT_CLASS (klass);
// sinktemplate should be a #GstStaticPadTemplate with direction
// %GST_PAD_SINK and name "sink"
gst_element_class_add_static_pad_template (gstelement_class, &sinktemplate);
gst_element_class_set_static_metadata (gstelement_class,
"Sink name",
"Sink",
"My Sink element",
"The author <my.sink@my.email>");
}
BaseSink will handle the prerolling correctly. This means that it will
return gst::StateChangeReturn::Async from a state change to PAUSED until the first
buffer arrives in this element. The base class will call the
GstBaseSinkClass::preroll 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, BaseSink will synchronise on the
clock using the times returned from GstBaseSinkClass::get_times. 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
property::BaseSink::sync property to false.
After synchronisation the virtual method GstBaseSinkClass::render will be
called. Subclasses should minimally implement this method.
Subclasses that synchronise on the clock in the GstBaseSinkClass::render
method 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.
These subclasses can use BaseSinkExt::wait_preroll() to perform the
blocking wait.
Upon receiving the EOS event in the PLAYING state, BaseSink will wait
for the clock to reach the time indicated by the stop time of the last
GstBaseSinkClass::get_times 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.
BaseSink will internally use the gst::EventType::Segment 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.
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 GstBaseSinkClass::set_caps function will be called when the subclass
should configure itself to process a specific media type.
The GstBaseSinkClass::start and GstBaseSinkClass::stop virtual methods
will be called when resources should be allocated. Any
GstBaseSinkClass::preroll, GstBaseSinkClass::render and
GstBaseSinkClass::set_caps function will be called between the
GstBaseSinkClass::start and GstBaseSinkClass::stop calls.
The GstBaseSinkClass::event virtual method will be called when an event is
received by BaseSink. Normally this method should only be overridden by
very specific elements (such as file sinks) which need to handle the
newsegment event specially.
The GstBaseSinkClass::unlock method is called when the elements should
unblock any blocking operations they perform in the
GstBaseSinkClass::render method. This is mostly useful when the
GstBaseSinkClass::render method performs a blocking write on a file
descriptor, for example.
The property::BaseSink::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
GstBaseSinkClass::get_times method does not return a valid start time or
max-lateness is set to -1 (the default).
Subclasses can use BaseSinkExt::set_max_lateness() to configure the
max-lateness value.
The property::BaseSink::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.
The property::BaseSink::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.
This is an Abstract Base Class, you cannot instantiate it.
Implements
BaseSinkExt, gst::prelude::ElementExt, gst::prelude::ObjectExt, trait@glib::ObjectExt, BaseSinkExtManual
Trait Implementations
This method returns an ordering between self and other values if one exists. Read more
This method tests less than (for self and other) and is used by the < operator. Read more
This method tests less than or equal to (for self and other) and is used by the <=
operator. Read more
This method tests greater than (for self and other) and is used by the > operator. Read more
Returns the type identifier of Self.
Auto Trait Implementations
Blanket Implementations
Mutably borrows from an owned value. Read more
Upcasts an object to a superclass or interface T. Read more
Upcasts an object to a reference of its superclass or interface T. Read more
Tries to downcast to a subclass or interface implementor T. Read more
Tries to downcast to a reference of its subclass or interface implementor T. Read more
Tries to cast to an object of type T. This handles upcasting, downcasting
and casting between interface and interface implementors. All checks are performed at
runtime, while downcast and upcast will do many checks at compile-time already. Read more
Tries to cast to reference to an object of type T. This handles upcasting, downcasting
and casting between interface and interface implementors. All checks are performed at
runtime, while downcast and upcast will do many checks at compile-time already. Read more
Casts to T unconditionally. Read more
Casts to &T unconditionally. Read more
Abort the state change of the element. This function is used by elements that do asynchronous state changes and find out something is wrong. Read more
Adds a pad (link point) to self. pad’s parent will be set to self;
see GstObjectExt::set_parent() for refcounting information. Read more
pub fn change_state(
&self,
transition: StateChange
) -> Result<StateChangeSuccess, StateChangeError>[src]
pub fn change_state(
&self,
transition: StateChange
) -> Result<StateChangeSuccess, StateChangeError>[src]Perform transition on self. Read more
pub fn continue_state(
&self,
ret: impl Into<StateChangeReturn>
) -> Result<StateChangeSuccess, StateChangeError>[src]
pub fn continue_state(
&self,
ret: impl Into<StateChangeReturn>
) -> Result<StateChangeSuccess, StateChangeError>[src]Commit the state change of the element and proceed to the next
pending state if any. This function is used
by elements that do asynchronous state changes.
The core will normally call this method automatically when an
element returned StateChangeReturn::Success from the state change function. Read more
v1_14 only.v1_14 only.v1_14 only.pub fn compatible_pad<P>(&self, pad: &P, caps: Option<&Caps>) -> Option<Pad> where
P: IsA<Pad>, [src]pub fn state(
&self,
timeout: impl Into<Option<ClockTime>>
) -> (Result<StateChangeSuccess, StateChangeError>, State, State)[src]pub fn link_filtered<P>(&self, dest: &P, filter: &Caps) -> Result<(), BoolError> where
P: IsA<Element>, [src]pub fn link_pads<P>(
&self,
srcpadname: Option<&str>,
dest: &P,
destpadname: Option<&str>
) -> Result<(), BoolError> where
P: IsA<Element>, [src]pub fn link_pads_filtered<P>(
&self,
srcpadname: Option<&str>,
dest: &P,
destpadname: Option<&str>,
filter: &Caps
) -> Result<(), BoolError> where
P: IsA<Element>, [src]pub fn link_pads_full<P>(
&self,
srcpadname: Option<&str>,
dest: &P,
destpadname: Option<&str>,
flags: PadLinkCheck
) -> Result<(), BoolError> where
P: IsA<Element>, [src]pub fn request_pad(
&self,
templ: &PadTemplate,
name: Option<&str>,
caps: Option<&Caps>
) -> Option<Pad>[src]v1_20 only.pub fn unlink_pads<P>(&self, srcpadname: &str, dest: &P, destpadname: &str) where
P: IsA<Element>, [src]pub fn connect_no_more_pads<F>(&self, f: F) -> SignalHandlerId where
F: 'static + Fn(&O) + Send + Sync, [src]pub fn connect_pad_added<F>(&self, f: F) -> SignalHandlerId where
F: 'static + Fn(&O, &Pad) + Send + Sync, [src]pub fn connect_pad_removed<F>(&self, f: F) -> SignalHandlerId where
F: 'static + Fn(&O, &Pad) + Send + Sync, [src]pub fn message_full<T>(
&self,
type_: ElementMessageType,
code: T,
message: Option<&str>,
debug: Option<&str>,
file: &str,
function: &str,
line: u32
) where
T: MessageErrorDomain, [src]pub fn message_full_with_details<T>(
&self,
type_: ElementMessageType,
code: T,
message: Option<&str>,
debug: Option<&str>,
file: &str,
function: &str,
line: u32,
structure: Structure
) where
T: MessageErrorDomain, [src]
pub fn message_full_with_details<T>(
&self,
type_: ElementMessageType,
code: T,
message: Option<&str>,
debug: Option<&str>,
file: &str,
function: &str,
line: u32,
structure: Structure
) where
T: MessageErrorDomain, [src]v1_10 only.pub fn add_property_deep_notify_watch(
&self,
property_name: Option<&str>,
include_value: bool
) -> NotifyWatchId[src]
pub fn add_property_deep_notify_watch(
&self,
property_name: Option<&str>,
include_value: bool
) -> NotifyWatchId[src]v1_10 only.pub fn add_property_notify_watch(
&self,
property_name: Option<&str>,
include_value: bool
) -> NotifyWatchId[src]
pub fn add_property_notify_watch(
&self,
property_name: Option<&str>,
include_value: bool
) -> NotifyWatchId[src]v1_10 only.v1_10 only.pub fn query_convert<V, U>(&self, src_val: V) -> Option<U> where
V: Into<GenericFormattedValue>,
U: SpecificFormattedValue, [src]pub fn query_convert_generic<V>(
&self,
src_val: V,
dest_format: Format
) -> Option<GenericFormattedValue> where
V: Into<GenericFormattedValue>, [src]pub fn seek<V>(
&self,
rate: f64,
flags: SeekFlags,
start_type: SeekType,
start: V,
stop_type: SeekType,
stop: V
) -> Result<(), BoolError> where
V: Into<GenericFormattedValue>, [src]pub fn seek_simple<V>(
&self,
seek_flags: SeekFlags,
seek_pos: V
) -> Result<(), BoolError> where
V: Into<GenericFormattedValue>, [src]v1_10 only.v1_10 only.pub fn add_control_binding<P>(&self, binding: &P) -> Result<(), BoolError> where
P: IsA<ControlBinding>, [src]
pub fn add_control_binding<P>(&self, binding: &P) -> Result<(), BoolError> where
P: IsA<ControlBinding>, [src]Attach the ControlBinding to the object. If there already was a
ControlBinding for this property it will be replaced. Read more
A default error function that uses g_printerr() to display the error message
and the optional debug string.. Read more
Gets the corresponding ControlBinding for the property. This should be
unreferenced again after use. Read more
Obtain the control-rate for this self. Audio processing Element
objects will use this rate to sub-divide their processing loop and call
sync_values() in between. The length of the processing segment
should be up to control-rate nanoseconds. Read more
Returns the parent of self. This function increases the refcount
of the parent object so you should gst_object_unref() it after usage. Read more
Generates a string describing the path of self in
the object hierarchy. Only useful (or used) for debugging. Read more
Gets the value for the given controlled property at the requested time. Read more
pub fn connect_parent_notify<F>(&self, f: F) -> SignalHandlerId where
F: 'static + Fn(&O) + Send + Sync, [src]Returns true if the object is an instance of (can be cast to) T.
pub fn set_properties(
&self,
property_values: &[(&str, &dyn ToValue)]
) -> Result<(), BoolError>[src]pub fn set_properties_from_value(
&self,
property_values: &[(&str, Value)]
) -> Result<(), BoolError>[src]pub fn set_property<'a, N, V>(
&self,
property_name: N,
value: V
) -> Result<(), BoolError> where
V: ToValue,
N: Into<&'a str>, [src]pub fn set_property_from_value<'a, N>(
&self,
property_name: N,
value: &Value
) -> Result<(), BoolError> where
N: Into<&'a str>, [src]pub fn property<'a, N>(&self, property_name: N) -> Result<Value, BoolError> where
N: Into<&'a str>, [src]Safety Read more
Safety Read more
Safety Read more
Safety Read more
pub fn connect_notify<F>(&self, name: Option<&str>, f: F) -> SignalHandlerId where
F: 'static + Fn(&T, &ParamSpec) + Send + Sync, [src]pub fn connect_notify_local<F>(
&self,
name: Option<&str>,
f: F
) -> SignalHandlerId where
F: 'static + Fn(&T, &ParamSpec), [src]pub unsafe fn connect_notify_unsafe<F>(
&self,
name: Option<&str>,
f: F
) -> SignalHandlerId where
F: Fn(&T, &ParamSpec), [src]pub fn has_property<'a, N>(&self, property_name: N, type_: Option<Type>) -> bool where
N: Into<&'a str>, [src]pub fn find_property<'a, N>(&self, property_name: N) -> Option<ParamSpec> where
N: Into<&'a str>, [src]pub fn connect<'a, N, F>(
&self,
signal_name: N,
after: bool,
callback: F
) -> Result<SignalHandlerId, BoolError> where
F: Fn(&[Value]) -> Option<Value> + Send + Sync + 'static,
N: Into<&'a str>, [src]Same as connect but takes a SignalId instead of a signal name.
pub fn connect_local<'a, N, F>(
&self,
signal_name: N,
after: bool,
callback: F
) -> Result<SignalHandlerId, BoolError> where
F: Fn(&[Value]) -> Option<Value> + 'static,
N: Into<&'a str>, [src]Same as connect_local but takes a SignalId instead of a signal name.
pub unsafe fn connect_unsafe<'a, N, F>(
&self,
signal_name: N,
after: bool,
callback: F
) -> Result<SignalHandlerId, BoolError> where
F: Fn(&[Value]) -> Option<Value>,
N: Into<&'a str>, [src]Same as connect_unsafe but takes a SignalId instead of a signal name.
Emit signal by signal id.
Emit signal with details by signal id.
Emit signal by it’s name.
pub fn bind_property<'a, O, N, M>(
&'a self,
source_property: N,
target: &'a O,
target_property: M
) -> BindingBuilder<'a> where
O: ObjectType,
N: Into<&'a str>,
M: Into<&'a str>, [src]Same as emit but takes Value for the arguments.
Same as emit_by_name but takes Value for the arguments.
Returns a SendValue clone of self.
impl<'a, T, C> FromValueOptional<'a> for T where
C: ValueTypeChecker<Error = ValueTypeMismatchOrNoneError>,
T: FromValue<'a, Checker = C>, [src]