#[repr(transparent)]
pub struct BaseEffect { /* private fields */ }
Expand description

A BaseEffect is some operation that applies an effect to the data it receives.

Time Effects

Some operations will change the timing of the stream data they receive in some way. In particular, the gst::Element that they wrap could alter the times of the segment they receive in a gst::EventType::Segment event, or the times of a seek they receive in a gst::EventType::Seek event. Such operations would be considered time effects since they translate the times they receive on their source to different times at their sink, and vis versa. This introduces two sets of time coordinates for the event: (internal) sink coordinates and (internal) source coordinates, where segment times are translated from the sink coordinates to the source coordinates, and seek times are translated from the source coordinates to the sink coordinates.

If you use such an effect in GES, you will need to inform GES of the properties that control the timing with BaseEffectExt::register_time_property(), and the effect’s timing behaviour using ges_base_effect_set_time_translation_funcs().

Note that a time effect should not have its has-internal-source set to true.

In addition, note that GES only fully supports time effects whose mapping from the source to sink coordinates (those applied to seeks) obeys:

  • Maps the time 0 to 0. So initial time-shifting effects are excluded.
  • Is monotonically increasing. So reversing effects, and effects that jump backwards in the stream are excluded.
  • Can handle a reasonable GstClockTime, relative to the project. So this would exclude a time effect with an extremely large speed-up that would cause the converted GstClockTime seeks to overflow.
  • Is ‘continuously reversible’. This essentially means that for every time in the sink coordinates, we can, to ‘good enough’ accuracy, calculate the corresponding time in the source coordinates. Moreover, this should correspond to how segment times are translated from sink to source.
  • Only depends on the registered time properties, rather than the state of the gst::Element or the data it receives. This would exclude, say, an effect that would speedup if there is more red in the image it receives.

Note that a constant-rate-change effect that is not extremely fast or slow would satisfy these conditions. For such effects, you may wish to use ges_effect_class_register_rate_property().

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

Implements

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

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Returns a copy of the value. Read more
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Formats the value using the given formatter. Read more
Preferred value to be used as setter for the associated ParamSpec.
Feeds this value into the given Hasher. Read more
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Restrict a value to a certain interval. Read more
This method tests for self and other values to be equal, and is used by ==.
This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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Returns the type identifier of Self.

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Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
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Upcasts an object to a superclass or interface T. Read more
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Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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Returns the class of the object in the given type T. Read more
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Sets the property property_name of the object to value value. Read more
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Return all ParamSpec of the properties of this object.
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Set arbitrary data on this object with the given key. Read more
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Retrieve previously set arbitrary data of this object with the given key. Read more
Set arbitrary data on this object with the given key. Read more
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Block a given signal handler. Read more
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Stop emission of the currently emitted signal.
Stop emission of the currently emitted signal by the (possibly detailed) signal name.
Connect to the signal signal_name on this object. Read more
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Connect a closure to the signal signal_name on this object. Read more
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Emit signal by signal id. Read more
Same as Self::emit but takes Value for the arguments.
Emit signal by its name. Read more
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Emit signal by signal id with details. Read more
Disconnect a previously connected signal handler.
Connect to the notify signal of the object. Read more
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Notify that the given property has changed its value. Read more
Notify that the given property has changed its value. Read more
Downgrade this object to a weak reference.
Add a callback to be notified when the Object is disposed.
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The resulting type after obtaining ownership.
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Performs the conversion.