Struct gstreamer_base::BaseSrc

source · [−]

#[repr(transparent)]
pub struct BaseSrc { /* private fields */ }

Expand description

This is a generic base class for source elements. The following types of sources are supported:

random access sources like files
seekable sources
live sources

The source can be configured to operate in any gst::Format with the BaseSrcExt::set_format() method. The currently set format determines the format of the internal gst::Segment and any gst::EventType::Segment events. The default format for BaseSrc is gst::Format::Bytes.

BaseSrc always supports push mode scheduling. If the following conditions are met, it also supports pull mode scheduling:

The format is set to gst::Format::Bytes (default).
GstBaseSrcClass::is_seekable returns true.

If all the conditions are met for operating in pull mode, BaseSrc is automatically seekable in push mode as well. The following conditions must be met to make the element seekable in push mode when the format is not gst::Format::Bytes:

GstBaseSrcClass::is_seekable returns true.
GstBaseSrcClass::query can convert all supported seek formats to the internal format as set with BaseSrcExt::set_format().
GstBaseSrcClass::do_seek is implemented, performs the seek and returns true.

When the element does not meet the requirements to operate in pull mode, the offset and length in the GstBaseSrcClass::create method should be ignored. It is recommended to subclass PushSrc instead, in this situation. If the element can operate in pull mode but only with specific offsets and lengths, it is allowed to generate an error when the wrong values are passed to the GstBaseSrcClass::create function.

BaseSrc has support for live sources. Live sources are sources that when paused discard data, such as audio or video capture devices. A typical live source also produces data at a fixed rate and thus provides a clock to publish this rate. Use BaseSrcExt::set_live() to activate the live source mode.

A live source does not produce data in the PAUSED state. This means that the GstBaseSrcClass::create method will not be called in PAUSED but only in PLAYING. To signal the pipeline that the element will not produce data, the return value from the READY to PAUSED state will be gst::StateChangeReturn::NoPreroll.

A typical live source will timestamp the buffers it creates with the current running time of the pipeline. This is one reason why a live source can only produce data in the PLAYING state, when the clock is actually distributed and running.

Live sources that synchronize and block on the clock (an audio source, for example) can use BaseSrcExt::wait_playing() when the GstBaseSrcClass::create function was interrupted by a state change to PAUSED.

The GstBaseSrcClass::get_times method can be used to implement pseudo-live sources. It only makes sense to implement the GstBaseSrcClass::get_times function if the source is a live source. The GstBaseSrcClass::get_times function should return timestamps starting from 0, as if it were a non-live source. The base class will make sure that the timestamps are transformed into the current running_time. The base source will then wait for the calculated running_time before pushing out the buffer.

For live sources, the base class will by default report a latency of 0. For pseudo live sources, the base class will by default measure the difference between the first buffer timestamp and the start time of get_times and will report this value as the latency. Subclasses should override the query function when this behaviour is not acceptable.

There is only support in BaseSrc for exactly one source pad, which should be named “src”. A source implementation (subclass of BaseSrc) should install a pad template in its class_init function, like so:

⚠️ The following code is in C ⚠️

static void
my_element_class_init (GstMyElementClass *klass)
{
  GstElementClass *gstelement_class = GST_ELEMENT_CLASS (klass);
  // srctemplate should be a #GstStaticPadTemplate with direction
  // %GST_PAD_SRC and name "src"
  gst_element_class_add_static_pad_template (gstelement_class, &srctemplate);

  gst_element_class_set_static_metadata (gstelement_class,
     "Source name",
     "Source",
     "My Source element",
     "The author <my.sink@my.email>");
}

Controlled shutdown of live sources in applications

Applications that record from a live source may want to stop recording in a controlled way, so that the recording is stopped, but the data already in the pipeline is processed to the end (remember that many live sources would go on recording forever otherwise). For that to happen the application needs to make the source stop recording and send an EOS event down the pipeline. The application would then wait for an EOS message posted on the pipeline’s bus to know when all data has been processed and the pipeline can safely be stopped.

An application may send an EOS event to a source element to make it perform the EOS logic (send EOS event downstream or post a GST_MESSAGE_SEGMENT_DONE on the bus). This can typically be done with the ElementExtManual::send_event() function on the element or its parent bin.

After the EOS has been sent to the element, the application should wait for an EOS message to be posted on the pipeline’s bus. Once this EOS message is received, it may safely shut down the entire pipeline.

This is an Abstract Base Class, you cannot instantiate it.

Implements

BaseSrcExt, gst::prelude::ElementExt, gst::prelude::ObjectExt, trait@glib::ObjectExt, BaseSrcExtManual

Struct gstreamer_base::BaseSrc

Controlled shutdown of live sources in applications

Implements

Implementations

impl BaseSrc

pub const NONE: Option<&'static BaseSrc>

Trait Implementations

impl Clone for BaseSrc

fn clone(&self) -> Self

fn clone_from(&mut self, source: &Self)

impl Debug for BaseSrc

fn fmt(&self, f: &mut Formatter<'_>) -> Result

impl Hash for BaseSrc

fn hash<H>(&self, state: &mut H) where H: Hasher,

fn hash_slice<H>(data: &[Self], state: &mut H) where H: Hasher,

impl<T: BaseSrcImpl> IsSubclassable<T> for BaseSrc

fn class_init(klass: &mut Class<Self>)

fn instance_init(instance: &mut InitializingObject<T>)

impl Ord for BaseSrc

fn cmp(&self, other: &Self) -> Ordering

fn max(self, other: Self) -> Self

fn min(self, other: Self) -> Self

fn clamp(self, min: Self, max: Self) -> Self

impl ParentClassIs for BaseSrc

type Parent = Element

impl<OT: ObjectType> PartialEq<OT> for BaseSrc

fn eq(&self, other: &OT) -> bool

fn ne(&self, other: &Rhs) -> bool

impl<OT: ObjectType> PartialOrd<OT> for BaseSrc

fn partial_cmp(&self, other: &OT) -> Option<Ordering>

fn lt(&self, other: &Rhs) -> bool

fn le(&self, other: &Rhs) -> bool

fn gt(&self, other: &Rhs) -> bool

fn ge(&self, other: &Rhs) -> bool

impl StaticType for BaseSrc

fn static_type() -> Type

impl Eq for BaseSrc

impl IsA<BaseSrc> for PushSrc

impl IsA<Element> for BaseSrc

impl IsA<Object> for BaseSrc

impl Send for BaseSrc

impl Sync for BaseSrc

Auto Trait Implementations

impl RefUnwindSafe for BaseSrc

impl Unpin for BaseSrc

impl UnwindSafe for BaseSrc

Blanket Implementations

impl<T> Any for T where T: 'static + ?Sized,

pub fn type_id(&self) -> TypeId

impl<T> Borrow<T> for T where T: ?Sized,

pub fn borrow(&self) -> &T

impl<T> BorrowMut<T> for T where T: ?Sized,

pub fn borrow_mut(&mut self) -> &mut T

impl<T> Cast for T where T: ObjectType,

fn upcast<T>(self) -> T where T: ObjectType, Self: IsA<T>,

fn upcast_ref<T>(&self) -> &T where T: ObjectType, Self: IsA<T>,

fn downcast<T>(self) -> Result<T, Self> where T: ObjectType, Self: CanDowncast<T>,

fn downcast_ref<T>(&self) -> Option<&T> where T: ObjectType, Self: CanDowncast<T>,

fn dynamic_cast<T>(self) -> Result<T, Self> where T: ObjectType,

fn dynamic_cast_ref<T>(&self) -> Option<&T> where T: ObjectType,

unsafe fn unsafe_cast<T>(self) -> T where T: ObjectType,

unsafe fn unsafe_cast_ref<T>(&self) -> &T where T: ObjectType,

impl<O> ElementExt for O where O: IsA<Element>,

pub fn abort_state(&self)

pub fn add_pad(&self, pad: &impl IsA<Pad>) -> Result<(), BoolError>

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

pub fn continue_state( &self, ret: impl Into<StateChangeReturn>) -> Result<StateChangeSuccess, StateChangeError>

pub fn create_all_pads(&self)

pub fn foreach_pad<P>(&self, func: P) -> bool where P: FnMut(&Element, &Pad) -> bool,

pub fn foreach_sink_pad<P>(&self, func: P) -> bool where P: FnMut(&Element, &Pad) -> bool,

pub fn foreach_src_pad<P>(&self, func: P) -> bool where P: FnMut(&Element, &Pad) -> bool,

pub fn base_time(&self) -> Option<ClockTime>

pub fn bus(&self) -> Option<Bus>

pub fn clock(&self) -> Option<Clock>

pub fn compatible_pad( &self, pad: &impl IsA<Pad>, caps: Option<&Caps>) -> Option<Pad>

pub fn compatible_pad_template( &self, compattempl: &PadTemplate) -> Option<PadTemplate>

pub fn context(&self, context_type: &str) -> Option<Context>

pub fn contexts(&self) -> Vec<Context, Global>ⓘNotable traits for Vec<u8, A>impl<A> Write for Vec<u8, A> where A: Allocator,

pub fn factory(&self) -> Option<ElementFactory>

pub fn start_time(&self) -> Option<ClockTime>

fn hash<H>(&self, state: &mut H) where
H: Hasher,

fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher,

impl<T> Any for T where
T: 'static + ?Sized,

impl<T> Borrow<T> for T where
T: ?Sized,

impl<T> BorrowMut<T> for T where
T: ?Sized,

impl<T> Cast for T where
T: ObjectType,

fn upcast<T>(self) -> T where
T: ObjectType,
Self: IsA<T>,

fn upcast_ref<T>(&self) -> &T where
T: ObjectType,
Self: IsA<T>,

fn downcast<T>(self) -> Result<T, Self> where
T: ObjectType,
Self: CanDowncast<T>,

fn downcast_ref<T>(&self) -> Option<&T> where
T: ObjectType,
Self: CanDowncast<T>,

fn dynamic_cast<T>(self) -> Result<T, Self> where
T: ObjectType,

fn dynamic_cast_ref<T>(&self) -> Option<&T> where
T: ObjectType,

unsafe fn unsafe_cast<T>(self) -> T where
T: ObjectType,

unsafe fn unsafe_cast_ref<T>(&self) -> &T where
T: ObjectType,

impl<O> ElementExt for O where
O: IsA<Element>,

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

pub fn continue_state(
&self,
ret: impl Into<StateChangeReturn>
) -> Result<StateChangeSuccess, StateChangeError>

pub fn foreach_pad<P>(&self, func: P) -> bool where
P: FnMut(&Element, &Pad) -> bool,

pub fn foreach_sink_pad<P>(&self, func: P) -> bool where
P: FnMut(&Element, &Pad) -> bool,

pub fn foreach_src_pad<P>(&self, func: P) -> bool where
P: FnMut(&Element, &Pad) -> bool,

pub fn compatible_pad(
&self,
pad: &impl IsA<Pad>,
caps: Option<&Caps>
) -> Option<Pad>

pub fn compatible_pad_template(
&self,
compattempl: &PadTemplate
) -> Option<PadTemplate>

pub fn contexts(&self) -> Vec<Context, Global>ⓘ
Notable traits for Vec<u8, A>
`impl<A> Write for Vec<u8, A> where A: Allocator,`

pub fn state(
&self,
timeout: impl Into<Option<ClockTime>>
) -> (Result<StateChangeSuccess, StateChangeError>, State, State )

pub fn link_filtered(
&self,
dest: &impl IsA<Element>,
filter: &Caps
) -> Result<(), BoolError>

pub fn link_pads(
&self,
srcpadname: Option<&str>,
dest: &impl IsA<Element>,
destpadname: Option<&str>
) -> Result<(), BoolError>

pub fn link_pads_filtered(
&self,
srcpadname: Option<&str>,
dest: &impl IsA<Element>,
destpadname: Option<&str>,
filter: &Caps
) -> Result<(), BoolError>

pub fn link_pads_full(
&self,
srcpadname: Option<&str>,
dest: &impl IsA<Element>,
destpadname: Option<&str>,
flags: PadLinkCheck
) -> Result<(), BoolError>

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

pub fn set_clock(
&self,
clock: Option<&impl IsA<Clock>>
) -> Result<(), BoolError>

pub fn set_state(
&self,
state: State
) -> Result<StateChangeSuccess, StateChangeError>

pub fn unlink_pads(
&self,
srcpadname: &str,
dest: &impl IsA<Element>,
destpadname: &str
)

pub fn connect_no_more_pads<F>(&self, f: F) -> SignalHandlerId where
F: 'static + Fn(&O) + Send + Sync,

pub fn connect_pad_added<F>(&self, f: F) -> SignalHandlerId where
F: 'static + Fn(&O, &Pad) + Send + Sync,

pub fn connect_pad_removed<F>(&self, f: F) -> SignalHandlerId where
F: 'static + Fn(&O, &Pad) + Send + Sync,

impl<O> ElementExtManual for O where
O: IsA<Element>,

pub fn pad_template_list(&self) -> Vec<PadTemplate, Global>ⓘ
Notable traits for Vec<u8, A>
`impl<A> Write for Vec<u8, A> where A: Allocator,`

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,

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,

pub fn pads(&self) -> Vec<Pad, Global>ⓘ
Notable traits for Vec<u8, A>
`impl<A> Write for Vec<u8, A> where A: Allocator,`

pub fn sink_pads(&self) -> Vec<Pad, Global>ⓘ
Notable traits for Vec<u8, A>
`impl<A> Write for Vec<u8, A> where A: Allocator,`

pub fn src_pads(&self) -> Vec<Pad, Global>ⓘ
Notable traits for Vec<u8, A>
`impl<A> Write for Vec<u8, A> where A: Allocator,`

pub fn add_property_deep_notify_watch(
&self,
property_name: Option<&str>,
include_value: bool
) -> NotifyWatchId

pub fn add_property_notify_watch(
&self,
property_name: Option<&str>,
include_value: bool
) -> NotifyWatchId

pub fn query_convert<V, U>(&self, src_val: V) -> Option<U> where
V: Into<GenericFormattedValue>,
U: SpecificFormattedValue,

pub fn query_convert_generic<V>(
&self,
src_val: V,
dest_format: Format
) -> Option<GenericFormattedValue> where
V: Into<GenericFormattedValue>,

pub fn query_duration<T>(&self) -> Option<T> where
T: SpecificFormattedValueIntrinsic,

pub fn query_duration_generic(
&self,
format: Format
) -> Option<GenericFormattedValue>

pub fn query_position<T>(&self) -> Option<T> where
T: SpecificFormattedValueIntrinsic,

pub fn query_position_generic(
&self,
format: Format
) -> Option<GenericFormattedValue>

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>,

pub fn seek_simple<V>(
&self,
seek_flags: SeekFlags,
seek_pos: V
) -> Result<(), BoolError> where
V: Into<GenericFormattedValue>,