Struct gstreamer_editing_services::TimelineElement

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

A TimelineElement will have some temporal extent in its corresponding timeline, controlled by its start and duration. This determines when its content will be displayed, or its effect applied, in the timeline. Several objects may overlap within a given Timeline, in which case their priority is used to determine their ordering in the timeline. Priority is mostly handled internally by Layer-s and Clip-s.

A timeline element can have a parent, such as a Clip, which is responsible for controlling its timing.

Editing

Elements can be moved around in their timeline by setting their start and duration using TimelineElementExt::set_start() and TimelineElementExt::set_duration(). Additionally, which parts of the underlying content are played in the timeline can be adjusted by setting the in-point using TimelineElementExt::set_inpoint(). The library also provides TimelineElementExt::edit(), with various EditMode-s, which can adjust these properties in a convenient way, as well as introduce similar changes in neighbouring or later elements in the timeline.

However, a timeline may refuse a change in these properties if they would place the timeline in an unsupported configuration. See Timeline for its overlap rules.

Additionally, an edit may be refused if it would place one of the timing properties out of bounds (such as a negative time value for start, or having insufficient internal content to last for the desired duration).

Time Coordinates

There are three main sets of time coordinates to consider when using timeline elements:

• Timeline coordinates: these are the time coordinates used in the output of the timeline in its Track-s. Each track share the same coordinates, so there is only one set of coordinates for the timeline. These extend indefinitely from 0. The times used for editing (including setting start and duration) use these coordinates, since these define when an element is present and for how long the element lasts for in the timeline.
• Internal source coordinates: these are the time coordinates used internally at the element’s output. This is only really defined for TrackElement-s, where it refers to time coordinates used at the final source pad of the wrapped gst::Element-s. However, these coordinates may also be used in a Clip in reference to its children. In particular, these are the coordinates used for in-point and max-duration.
• Internal sink coordinates: these are the time coordinates used internally at the element’s input. A Source has no input, so these would be undefined. Otherwise, for most TrackElement-s these will be the same set of coordinates as the internal source coordinates because the element does not change the timing internally. Only BaseEffect can support elements where these are different. See BaseEffect for more information.

You can determine the timeline time for a given internal source time in a Track in a Clip using ClipExt::timeline_time_from_internal_time(), and vice versa using ClipExt::internal_time_from_timeline_time(), for the purposes of editing and setting timings properties.

Children Properties

If a timeline element owns another gst::Object and wishes to expose some of its properties, it can do so by registering the property as one of the timeline element’s children properties using TimelineElementExt::add_child_property(). The registered property of the child can then be read and set using the TimelineElementExt::child_property() and TimelineElementExt::set_child_property() methods, respectively. Some sub-classed objects will be created with pre-registered children properties; for example, to expose part of an underlying gst::Element that is used internally. The registered properties can be listed with TimelineElementExt::list_children_properties().

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

Properties

duration

The duration that the element is in effect for in the timeline (a time difference in nanoseconds using the time coordinates of the timeline). For example, for a source element, this would determine for how long it should output its internal content for. For an operation element, this would determine for how long its effect should be applied to any source content.

Readable | Writeable

in-point

The initial offset to use internally when outputting content (in nanoseconds, but in the time coordinates of the internal content).

For example, for a VideoUriSource that references some media file, the “internal content” is the media file data, and the in-point would correspond to some timestamp in the media file. When playing the timeline, and when the element is first reached at timeline-time start, it will begin outputting the data from the timestamp in-point onwards, until it reaches the end of its duration in the timeline.

For elements that have no internal content, this should be kept as 0.

Readable | Writeable

max-duration

The full duration of internal content that is available (a time difference in nanoseconds using the time coordinates of the internal content).

This will act as a cap on the in-point of the element (which is in the same time coordinates), and will sometimes be used to limit the duration of the element in the timeline.

For example, for a VideoUriSource that references some media file, this would be the length of the media file.

For elements that have no internal content, or whose content is indefinite, this should be kept as GST_CLOCK_TIME_NONE.

Readable | Writeable | Construct

name

The name of the element. This should be unique within its timeline.

Readable | Writeable | Construct

parent

The parent container of the element.

Readable | Writeable

priority

The priority of the element.

Readable | Writeable

serialize

Whether the element should be serialized.

Readable | Writeable

start

The starting position of the element in the timeline (in nanoseconds and in the time coordinates of the timeline). For example, for a source element, this would determine the time at which it should start outputting its internal content. For an operation element, this would determine the time at which it should start applying its effect to any source content.

Readable | Writeable

timeline

The timeline that the element lies within.

Readable | Writeable

Signals

child-property-added

Emitted when the element has a new child property registered. See TimelineElementExt::add_child_property().

Note that some GES elements will be automatically created with pre-registered children properties. You can use TimelineElementExt::list_children_properties() to list these.

child-property-removed

Emitted when the element has a child property unregistered. See TimelineElementExt::remove_child_property().

deep-notify

Emitted when a child of the element has one of its registered properties set. See TimelineElementExt::add_child_property(). Note that unlike notify, a child property name can not be used as a signal detail.

Detailed

MetaContainer

notify-meta

This is emitted for a meta container whenever the metadata under one of its fields changes, is set for the first time, or is removed. In the latter case, value will be None.

Detailed

Implements

TimelineElementExt, glib::ObjectExt, ExtractableExt, MetaContainerExt, [TimelineElementExtManual][trait@crate::prelude::TimelineElementExtManual]

Implementations

impl TimelineElement

pub const NONE: Option<&'static TimelineElement> = None

Trait Implementations

impl Clone for TimelineElement

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for TimelineElement

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

Formats the value using the given formatter.

impl HasParamSpec for TimelineElement

type ParamSpec = ParamSpecObject

type SetValue = TimelineElement

Preferred value to be used as setter for the associated ParamSpec.

type BuilderFn = fn(_: &str) -> ParamSpecObjectBuilder<'_, TimelineElement>

fn param_spec_builder() -> Self::BuilderFn

impl Hash for TimelineElement

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

Feeds this value into the given Hasher.

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

Feeds a slice of this type into the given Hasher.

impl Ord for TimelineElement

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

This method returns an Ordering between self and other.

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

Compares and returns the maximum of two values.

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

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Selfwhere
    Self: Sized + PartialOrd<Self>,

Restrict a value to a certain interval.

impl ParentClassIs for TimelineElement

type Parent = Object

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

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

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

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

This method returns an ordering between self and other values if one exists.

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

This method tests less than (for self and other) and is used by the < operator.

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

This method tests less than or equal to (for self and other) and is used by the <= operator.

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

This method tests greater than (for self and other) and is used by the > operator.

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

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl StaticType for TimelineElement

fn static_type() -> Type

Returns the type identifier of Self.

impl Eq for TimelineElement

impl IsA<Extractable> for TimelineElement

impl IsA<MetaContainer> for TimelineElement

impl IsA<TimelineElement> for AudioSource

impl IsA<TimelineElement> for AudioTestSource

impl IsA<TimelineElement> for AudioTransition

impl IsA<TimelineElement> for AudioUriSource

impl IsA<TimelineElement> for BaseEffect

impl IsA<TimelineElement> for BaseEffectClip

impl IsA<TimelineElement> for BaseTransitionClip

impl IsA<TimelineElement> for Clip

impl IsA<TimelineElement> for Container

impl IsA<TimelineElement> for Effect

impl IsA<TimelineElement> for EffectClip

impl IsA<TimelineElement> for Group

impl IsA<TimelineElement> for ImageSource

impl IsA<TimelineElement> for MultiFileSource

impl IsA<TimelineElement> for Operation

impl IsA<TimelineElement> for OperationClip

impl IsA<TimelineElement> for OverlayClip

impl IsA<TimelineElement> for Source

impl IsA<TimelineElement> for SourceClip

impl IsA<TimelineElement> for TestClip

impl IsA<TimelineElement> for TextOverlay

impl IsA<TimelineElement> for TextOverlayClip

impl IsA<TimelineElement> for TitleClip

impl IsA<TimelineElement> for TitleSource

impl IsA<TimelineElement> for TrackElement

impl IsA<TimelineElement> for Transition

impl IsA<TimelineElement> for TransitionClip

impl IsA<TimelineElement> for UriClip

impl IsA<TimelineElement> for VideoSource

impl IsA<TimelineElement> for VideoTestSource

impl IsA<TimelineElement> for VideoTransition

impl IsA<TimelineElement> for VideoUriSource