Trait gstreamer::subclass::prelude::ElementImpl

pub trait ElementImpl: ElementImplExt + GstObjectImpl + Send + Sync {
    // Provided methods
    fn metadata() -> Option<&'static ElementMetadata> { ... }
    fn pad_templates() -> &'static [PadTemplate] { ... }
    fn change_state(
        &self,
        transition: StateChange,
    ) -> Result<StateChangeSuccess, StateChangeError> { ... }
    fn request_new_pad(
        &self,
        templ: &PadTemplate,
        name: Option<&str>,
        caps: Option<&Caps>,
    ) -> Option<Pad> { ... }
    fn release_pad(&self, pad: &Pad) { ... }
    fn send_event(&self, event: Event) -> bool { ... }
    fn query(&self, query: &mut QueryRef) -> bool { ... }
    fn set_context(&self, context: &Context) { ... }
    fn set_clock(&self, clock: Option<&Clock>) -> bool { ... }
    fn provide_clock(&self) -> Option<Clock> { ... }
    fn post_message(&self, msg: Message) -> bool { ... }
}

Provided Methods

fn metadata() -> Option<&'static ElementMetadata>

fn pad_templates() -> &'static [PadTemplate]

fn change_state( &self, transition: StateChange, ) -> Result<StateChangeSuccess, StateChangeError>

Perform transition on self.

This function must be called with STATE_LOCK held and is mainly used internally.

transition

the requested transition

Returns

the StateChangeReturn of the state transition.

fn request_new_pad( &self, templ: &PadTemplate, name: Option<&str>, caps: Option<&Caps>, ) -> Option<Pad>

Retrieves a request pad from the element according to the provided template. Pad templates can be looked up using ElementFactory::static_pad_templates().

The pad should be released with ElementExt::release_request_pad().

templ

a PadTemplate of which we want a pad of.

name

the name of the request Pad to retrieve. Can be None.

caps

the caps of the pad we want to request. Can be None.

Returns

requested Pad if found, otherwise None. Release after usage.

fn release_pad(&self, pad: &Pad)

called when a request pad is to be released

fn send_event(&self, event: Event) -> bool

Sends an event to an element. If the element doesn’t implement an event handler, the event will be pushed on a random linked sink pad for downstream events or a random linked source pad for upstream events.

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

MT safe.

event

the Event to send to the element.

Returns

true if the event was handled. Events that trigger a preroll (such as flushing seeks and steps) will emit GST_MESSAGE_ASYNC_DONE.

fn query(&self, query: &mut QueryRef) -> bool

Performs a query on the given element.

For elements that don’t implement a query handler, this function forwards the query to a random srcpad or to the peer of a random linked sinkpad of this element.

Please note that some queries might need a running pipeline to work.

query

the Query.

Returns

true if the query could be performed.

MT safe.

fn set_context(&self, context: &Context)

Sets the context of the element. Increases the refcount of the context.

MT safe.

context

the Context to set.

fn set_clock(&self, clock: Option<&Clock>) -> bool

Sets the clock for the element. This function increases the refcount on the clock. Any previously set clock on the object is unreffed.

clock

the Clock to set for the element.

Returns

true if the element accepted the clock. An element can refuse a clock when it, for example, is not able to slave its internal clock to the clock or when it requires a specific clock to operate.

MT safe.

fn provide_clock(&self) -> Option<Clock>

Get the clock provided by the given element.

An element is only required to provide a clock in the PAUSED state. Some elements can provide a clock in other states.

Returns

the GstClock provided by the element or None if no clock could be provided. Unref after usage.

MT safe.

fn post_message(&self, msg: Message) -> bool

Post a message on the element’s Bus. This function takes ownership of the message; if you want to access the message after this call, you should add an additional reference before calling.

message

a Message to post

Returns

true if the message was successfully posted. The function returns false if the element did not have a bus.

MT safe.

Object Safety

This trait is not object safe.

Implementors