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

Timeline is the central object for any multimedia timeline.

A timeline is composed of a set of Track-s and a set of Layer-s, which are added to the timeline using TimelineExt::add_track() and TimelineExt::append_layer(), respectively.

The contained tracks define the supported types of the timeline and provide the media output. Essentially, each track provides an additional source gst::Pad.

Most usage of a timeline will likely only need a single AudioTrack and/or a single VideoTrack. You can create such a timeline with new_audio_video(). After this, you are unlikely to need to work with the tracks directly.

A timeline’s layers contain Clip-s, which in turn control the creation of TrackElement-s, which are added to the timeline’s tracks. See signal::Timeline::select-tracks-for-object if you wish to have more control over which track a clip’s elements are added to.

The layers are ordered, with higher priority layers having their content prioritised in the tracks. This ordering can be changed using TimelineExt::move_layer().

Editing

See TimelineElement for the various ways the elements of a timeline can be edited.

If you change the timing or ordering of a timeline’s TimelineElement-s, then these changes will not actually be taken into account in the output of the timeline’s tracks until the TimelineExt::commit() method is called. This allows you to move its elements around, say, in response to an end user’s mouse dragging, with little expense before finalising their effect on the produced data.

Overlaps and Auto-Transitions

There are certain restrictions placed on how Source-s may overlap in a Track that belongs to a timeline. These will be enforced by GES, so the user will not need to keep track of them, but they should be aware that certain edits will be refused as a result if the overlap rules would be broken.

Consider two Source-s, A and B, with start times startA and startB, and end times endA and endB, respectively. The start time refers to their property::TimelineElement::start, and the end time is their property::TimelineElement::start + property::TimelineElement::duration. These two sources overlap if:

  • they share the same property::TrackElement::track (non None), which belongs to the timeline;
  • they share the same GES_TIMELINE_ELEMENT_LAYER_PRIORITY; and
  • startA < endB and startB < endA .

Note that when startA = endB or startB = endA then the two sources will touch at their edges, but are not considered overlapping.

If, in addition, startA < startB < endA, then we can say that the end of A overlaps the start of B.

If, instead, startA <= startB and endA >= endB, then we can say that A fully overlaps B.

The overlap rules for a timeline are that:

  1. One source cannot fully overlap another source.
  2. A source can only overlap the end of up to one other source at its start.
  3. A source can only overlap the start of up to one other source at its end.

The last two rules combined essentially mean that at any given timeline position, only up to two Source-s may overlap at that position. So triple or more overlaps are not allowed.

If you switch on property::Timeline::auto-transition, then at any moment when the end of one source (the first source) overlaps the start of another (the second source), a TransitionClip will be automatically created for the pair in the same layer and it will cover their overlap. If the two elements are edited in a way such that the end of the first source no longer overlaps the start of the second, the transition will be automatically removed from the timeline. However, if the two sources still overlap at the same edges after the edit, then the same transition object will be kept, but with its timing and layer adjusted accordingly.

Saving

To save/load a timeline, you can use the TimelineExt::load_from_uri() and TimelineExt::save_to_uri() methods that use the default format.

Playing

A timeline is a gst::Bin with a source gst::Pad for each of its tracks, which you can fetch with TimelineExt::pad_for_track(). You will likely want to link these to some compatible sink gst::Element-s to be able to play or capture the content of the timeline.

You can use a Pipeline to easily preview/play the timeline’s content, or render it to a file.

Implements

TimelineExt, [trait@gst::prelude::BinExt], gst::prelude::ElementExt, gst::prelude::GstObjectExt, glib::ObjectExt, gst::prelude::ChildProxyExt, ExtractableExt, MetaContainerExt

Implementations

Creates a new empty timeline.

Returns

The new timeline.

Creates a new timeline containing a single AudioTrack and a single VideoTrack.

Returns

The new timeline.

Creates a timeline from the given URI.

uri

The URI to load from

Returns

A new timeline if the uri was loaded successfully, or None if the uri could not be loaded.

Trait Implementations

Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Formats the value using the given formatter. Read more
Returns the “default value” for a type. Read more
Feeds this value into the given Hasher. Read more
Feeds a slice of this type into the given Hasher. Read more
This method returns an Ordering between self and other. Read more
Compares and returns the maximum of two values. Read more
Compares and returns the minimum of two values. Read more
Restrict a value to a certain interval. Read more
This method tests for self and other values to be equal, and is used by ==. Read more
This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason. Read more
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
This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
Returns the type identifier of Self.

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
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
Emits the signal::ChildProxy::child-added signal. Read more
Emits the signal::ChildProxy::child-removed signal. Read more
Fetches a child by its number. Read more
Looks up a child element by the given name. Read more
Available on crate feature v1_22 only.
Looks up a child element by the given full-path name. Read more
Gets the number of child objects this parent contains. Read more
Will be emitted after the object was added to the child_proxy. Read more
Will be emitted after the object was removed from the child_proxy. Read more
Looks up which object and GParamSpec would be effected by the given name. Read more
Gets a single property using the GstChildProxy mechanism. You are responsible for freeing it by calling [glib::Value::unset()][crate::glib::Value::unset()] Read more
Sets a single property using the GstChildProxy mechanism. 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
Perform transition on self. Read more
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
Performs a query on the given element. Read more
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. Read more

Returns the argument unchanged.

Adds the given element to the bin. Sets the element’s parent, and thus takes ownership of the element. An element can only be added to one bin. Read more
Recursively looks for elements with an unlinked pad of the given direction within the specified bin and returns an unlinked pad if one is found, or None otherwise. If a pad is found, the caller owns a reference to it and should use gst_object_unref() on the pad when it is not needed any longer. Read more
Looks for an element inside the bin that implements the given interface. If such an element is found, it returns the element. You can cast this element to the given interface afterwards. If you want all elements that implement the interface, use GstBinExtManual::iterate_all_by_interface(). This function recurses into child bins. Read more
Gets the element with the given name from a bin. This function recurses into child bins. Read more
Gets the element with the given name from this bin. If the element is not found, a recursion is performed on the parent bin. Read more
Returns Read more
Queries self for the current latency and reconfigures this latency on all the elements using a LATENCY event. Read more
Removes the element from the bin, unparenting it as well. Unparenting the element means that the element will be dereferenced, so if the bin holds the only reference to the element, the element will be freed in the process of removing it from the bin. If you want the element to still exist after removing, you need to call gst_object_ref() before removing it from the bin. Read more
Suppresses the given flags on the bin. ElementFlags of a child element are propagated when it is added to the bin. When suppressed flags are set, those specified flags will not be propagated to the bin. Read more
Synchronizes the state of every child of self with the state of self. See also ElementExt::sync_state_with_parent(). Read more
If set to true, the bin will handle asynchronous state changes. This should be used only if the bin subclass is modifying the state of its children on its own. Read more
If set to true, the bin will handle asynchronous state changes. This should be used only if the bin subclass is modifying the state of its children on its own. Read more
Forward all children messages, even those that would normally be filtered by the bin. This can be interesting when one wants to be notified of the EOS state of individual elements, for example. Read more
Forward all children messages, even those that would normally be filtered by the bin. This can be interesting when one wants to be notified of the EOS state of individual elements, for example. Read more
Will be emitted after the element was added to sub_bin. Read more
Will be emitted after the element was removed from sub_bin. Read more
Will be emitted after the element was added to the bin. Read more
Will be emitted after the element was removed from the bin. Read more
Available on crate feature v1_18 only.
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 a copy of the name of self. Caller should g_free() the return value after usage. For a nameless object, this returns None, which you can safely g_free() as well. 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

Calls U::from(self).

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

Returns true if the object is an instance of (can be cast to) T.
Returns the type of the object.
Returns the ObjectClass of the object. Read more
Returns the class of the object.
Returns the class of the object in the given type T. Read more
Returns the interface T of the object. Read more
Sets the property property_name of the object to value value. Read more
Sets the property property_name of the object to value value. Read more
Sets multiple properties of the object at once. Read more
Sets multiple properties of the object at once. Read more
Gets the property property_name of the object and cast it to the type V. Read more
Gets the property property_name of the object. Read more
Check if the object has a property property_name of the given type_. Read more
Get the type of the property property_name of this object. Read more
Get the ParamSpec of the property property_name of this object.
Return all ParamSpec of the properties of this object.
Freeze all property notifications until the return guard object is dropped. Read more
Set arbitrary data on this object with the given key. Read more
Return previously set arbitrary data of this object with the given key. Read more
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
Return previously set arbitrary data of this object with the given key. Read more
Retrieve previously set arbitrary data of this object with the given key. Read more
Block a given signal handler. Read more
Unblock a given signal handler.
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
Connect to the signal signal_id on this object. Read more
Connect to the signal signal_name on this object. Read more
Connect to the signal signal_id on this object. Read more
Connect to the signal signal_name on this object. Read more
Connect to the signal signal_id on this object. Read more
Connect a closure to the signal signal_name on this object. Read more
Connect a closure to the signal signal_id on this object. Read more
Limits the lifetime of closure to the lifetime of the object. When the object’s reference count drops to zero, the closure will be invalidated. An invalidated closure will ignore any calls to invoke_with_values, or invoke when using Rust closures. Read more
Emit signal by signal id. Read more
Same as Self::emit but takes Value for the arguments.
Emit signal by its name. Read more
Emit signal by its name. Read more
Emit signal by its name with details. Read more
Emit signal by its name with details. Read more
Emit signal by signal id with details. Read more
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
Connect to the notify signal of the object. Read more
Connect to the notify signal of the object. Read more
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.
Add a callback to be notified when the Object is disposed. Read more
Bind property source_property on this object to the target_property on the target object. Read more
Returns the strong reference count of this object.
Runs the dispose mechanism of the object. Read more
Ensures that the type has been registered with the type system.
The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.