mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2024-11-14 05:12:09 +00:00
f8037f857d
We used to have a ges_track_object_get/set_child_property that was in
fact letting user set/get various properties at once, rename it to
get/set_properties, and implement:
API:
ges_track_object_get_child_property (GESTrackObject *object, const gchar
*property_name, GValue * value);
ges_track_object_set_child_property (GESTrackObject *object, const gchar
*property_name, GValue * value);
370 lines
12 KiB
Text
370 lines
12 KiB
Text
Effects
|
|
-------
|
|
|
|
Summary
|
|
-------
|
|
1. Basic ideas
|
|
2. Problems
|
|
3. Propositions to solve those problems
|
|
A. The registry
|
|
B. Effects configurability
|
|
C. Keyframes
|
|
4. Use-cases
|
|
5. API draft
|
|
|
|
The goal of this proposal is to design a simple way to handle effects through an
|
|
API which would allow developers to handle any use-cases.
|
|
|
|
1. Basic ideas
|
|
----------------
|
|
|
|
* GESTrackEffects are subclasses of GESTrackOperation
|
|
|
|
* You can add effects on any clip or layer
|
|
|
|
* You can add effects over several clips and control them as a unique effect.
|
|
|
|
* Effects are configurable and those properties can change during time
|
|
|
|
* We must be able to handle third-party effect providers, like the
|
|
gnome-video-effects standard.
|
|
|
|
* We must be able to implement complex effects. This means effects that are
|
|
more than adding GstElement-s to the timeline. It can also mean effects
|
|
that apply both video and audio changes.
|
|
|
|
2. Problems
|
|
----------
|
|
* We must be able to provide a list of effects available on the system at
|
|
runtime.
|
|
|
|
* We must be able to configure effects through an API in GES
|
|
withtout having to access the GstElements properties directly.
|
|
|
|
* We should also expose the GstElement-s contained in an effect so
|
|
it is possible for people to control their properties as they wish.
|
|
|
|
* We must be able to implement and handle complexe effects directly in GES
|
|
|
|
* We must be able to configure effects through time -> Keyframes without
|
|
duplicating code from GStreamer
|
|
|
|
|
|
3. Propositions to solve those problems
|
|
---------------------------------------
|
|
|
|
A. The registry => Still to design
|
|
|
|
We could implement a GESRegistry which would actually
|
|
retrieve elements (effects) from the GSTRegistry and any other mean
|
|
such as gnome-video-effects to let us get all the effects that are present
|
|
on the system....
|
|
This way the developers could have the list of all the effects
|
|
that are installed on the system pretty easily.
|
|
|
|
B. Effects configurability
|
|
|
|
The idea to be able to configure effects through a simple API in GES would
|
|
be to add an API in GESTrackObject to access the gst-object properties that
|
|
user would like to configure.
|
|
We would also have a method to set those properties easily.
|
|
|
|
We should also find a way to handle that in the case of systems such as
|
|
gnome-effects
|
|
|
|
C. Keyframes
|
|
|
|
We may want to handle this use-case directly in GES and for any kind of
|
|
time related configuration? FIXME
|
|
=> Special specifications for that?
|
|
|
|
4. Use-cases
|
|
-----------
|
|
|
|
UC-1. The user wants to add an effect to an entire clip => GESTimelineObject
|
|
new API
|
|
|
|
UC-2. The developer wants to allow users to configure effects => New
|
|
GESTrackOperation API
|
|
|
|
UC-3. The user wants to add an effect on a specific portion of a clip, we
|
|
should allow him to specify a portion of the clip where the effect should be
|
|
applied.
|
|
|
|
UC-4. We want to implement an effect which isn't only composed by a bin, but
|
|
is more complexe than that (ex: "effect '24'") => we have the
|
|
GESTrackOperation which is the base class (abstract) for this kind of
|
|
implementation. This class should implement vmethods to get/set configurable
|
|
properties.
|
|
|
|
UC-5. A developer wants to implement effect which handle music and video at
|
|
the same time, Would the solution be to implement a GESTimelineEffect
|
|
to handle this special usecase? FIXME
|
|
|
|
UC-6. The developers wants to configure each elements of an effect the way
|
|
he wants
|
|
with a full control over it.
|
|
|
|
UC-7. Developers want to expose all effects present on the system to the
|
|
end-user
|
|
|
|
5. API draft
|
|
------------
|
|
|
|
|
|
A. GESTrackObject new API
|
|
|
|
signals:
|
|
-------
|
|
* deep-notify: emited when a usefull property of a GstElement
|
|
contained in the GESTrackObject changes
|
|
=> DONE
|
|
|
|
/**
|
|
* ges_track_object_list_children_properties:
|
|
*
|
|
* @object: The origin #GESTrackObject
|
|
*
|
|
* A convenience method that lists all the usefull configurable properties
|
|
* of the GstElement-s contained in @object.
|
|
*
|
|
* Returns: an array of GParamSpec of the configurable properties of the
|
|
* GstElement-s contained in @object or %NULL if a problem occurred.
|
|
*/
|
|
GParamSpec **
|
|
ges_track_object_list_children_properties (GESTrackObject *object);
|
|
|
|
-> Usecases: Let user know all the property he can configure.
|
|
=> Waiting for GESMaterial
|
|
|
|
/**
|
|
* ges_track_object_set_child_property:
|
|
*
|
|
* @object: The origin #GESTrackObject
|
|
* @property_name: The name of the property
|
|
* @value: the value
|
|
*
|
|
* Sets a property of a GstElement contained in @object.
|
|
*
|
|
*/
|
|
void ges_track_object_set_child_property (GESTrackObject *object,
|
|
const gchar *property_name,
|
|
GValue * value);
|
|
-> Usecases:
|
|
+ Let user configure effects easily (UC-3)
|
|
=> DONE
|
|
|
|
/**
|
|
* ges_track_object_get_child_property:
|
|
*
|
|
* @object: The origin #GESTrackObject
|
|
* @property_name: The name of the property
|
|
* @value: return location for the property value
|
|
*
|
|
* Gets a property of a GstElement contained in @object.
|
|
*/
|
|
void ges_track_object_get_child_property (GESTrackObject *object,
|
|
const gchar *property_name,
|
|
GValue * value);
|
|
=> DONE
|
|
|
|
/**
|
|
* ges_track_object_get_material:
|
|
*
|
|
* @object: The origin #GESTrackObject
|
|
*
|
|
* This is a convenience method to get the #GESMaterial
|
|
* from which @object has been made.
|
|
*
|
|
* Returns: The material from which @object has been made or %NULL
|
|
* if @object has been made by another mean
|
|
*/
|
|
GESMaterial *ges_track_object_get_material (GESTrackObject *object);
|
|
=> Waiting for GESMaterial
|
|
|
|
B. GESTimelineObject new API
|
|
|
|
signals:
|
|
-------
|
|
* effect-added: emited when an effect is added
|
|
* effect-removed: emited when an effect is removed
|
|
=> DONE
|
|
|
|
/**
|
|
* ges_timeline_object_add_effect:
|
|
*
|
|
* @object: The origin #GESTimelineObject
|
|
* @effect_material: The #GESEffect from which to create the effect
|
|
* @position: The top position you want to give to the effect,
|
|
* -1 if you want it to be added at the end of effects.
|
|
*
|
|
* Adds a new effect corresponding to @effect_material to the
|
|
* #GESTimelineObject
|
|
*
|
|
* Returns: The newly created #GESTrackEffect, or %NULL if there was an
|
|
* error.
|
|
*/
|
|
GESTrackEffect *ges_timeline_object_add_effect (GESTimelineObject *object,
|
|
GESEffect *effect_material,
|
|
gint position);
|
|
=> Waiting for GESMaterial
|
|
|
|
/**
|
|
* ges_timeline_object_get_effects:
|
|
*
|
|
* @object: The origin #GESTimelineObject
|
|
*
|
|
* Returns: a #GList of the #GESTrackEffect that are applied on
|
|
* @object order by ascendant priorities.
|
|
* The refcount of the objects will be increased. The user will have to
|
|
* unref each #GESTrackOperation and free the #GList.
|
|
*/
|
|
GList *
|
|
ges_timeline_object_get_effects (GESTimelineObject *object);
|
|
-> Usecases:
|
|
+ First step to allow the configuration of effects (UC-3)
|
|
=> DONE
|
|
|
|
/**
|
|
* ges_timeline_object_set_top_effect_position:
|
|
*
|
|
* @object: The origin #GESTimelineObject
|
|
* @effect: The #GESTrackEffect to move
|
|
* @newposition: the new position at which to move the @effect
|
|
*
|
|
* Returns: %TRUE if @effect was successfuly moved, %FALSE otherwize.
|
|
*/
|
|
gboolean
|
|
ges_timeline_object_set_top_effect_position (GESTimelineObject *object,
|
|
GESTrackEffect *effect, guint newposition);
|
|
=> DONE
|
|
|
|
/**
|
|
* ges_timeline_object_get_top_effect_position:
|
|
*
|
|
* @object: The origin #GESTimelineObject
|
|
* @effect: The #GESTrackEffect we want to get the top position from
|
|
*
|
|
* Gets the top position of an effect.
|
|
*
|
|
* Returns: The top position of the effect, -1 if something went wrong.
|
|
*/
|
|
gint
|
|
ges_timeline_object_get_top_effect_position (GESTimelineObject *object,
|
|
GESTrackEffect *effect);
|
|
=> DONE
|
|
|
|
C - The GESTrackEffect API:
|
|
-> This is an empty abstract class
|
|
=> DONE
|
|
|
|
D - The GESTrackParseLaunchEffect API:
|
|
This is a parse-launch based implementation of TrackEffect.
|
|
|
|
/**
|
|
* ges_track_parse_launch_effect_new:
|
|
*
|
|
* @bin_dec: The gst-launch like bin description of the effect
|
|
*
|
|
* Creates a new #GESTrackEffect from the description of the bin. This is
|
|
* a convenience method for testing puposes.
|
|
*
|
|
* Returns: a newly created #GESTrackEffect, or %NULL if something went
|
|
* wrong.
|
|
*/
|
|
GESTrackEffect *ges_track_parse_launch_effect_new (GESTrackEffect *effect,
|
|
const gchar *bin_desc);
|
|
=> DONE
|
|
|
|
E - The GESTrackMaterialEffect API:
|
|
/**
|
|
* ges_track_material_effect:
|
|
*
|
|
* @effect_material: The #GESEffect from which to create this
|
|
* #GESTrackEffect
|
|
*
|
|
* Creates a new #GESTrackEffect from a #GESEffect
|
|
*
|
|
* Returns: a newly created #GESTrackEffect, or %NULL if something went
|
|
* wrong.
|
|
*/
|
|
GESTrackEffect *ges_track_material_effect_new (GESTrackEffect *effect,
|
|
GESEffect *effect_material);
|
|
=> Waiting for GESMaterial
|
|
|
|
F - The GESTimelineEffect API:
|
|
-> This is an empty abstract class
|
|
=> DONE
|
|
|
|
-> Usecases: The user wants to control multiple effects in sync. The user
|
|
wants to add an effect to the whole timeline. The user wants
|
|
to had an effect to a segment of the timeline without caring
|
|
bout what clip it is applied on.
|
|
|
|
G - The GESTimelineParseLaunchEffect API:
|
|
This is a parse-launch based implementation of TimelineEffect.
|
|
|
|
/**
|
|
* ges_timeline_parse_launch_effect_new_from_bin_desc:
|
|
* @video_bin_description: The gst-launch like bin description of the effect
|
|
* @audio_bin_description: The gst-launch like bin description of the effect
|
|
*
|
|
* Creates a new #GESTimelineParseLaunchEffect from the description of the bin.
|
|
*
|
|
* Returns: a newly created #GESTimelineParseLaunchEffect, or %NULL if something went
|
|
* wrong.
|
|
*/
|
|
GESTimelineParseLaunchEffect *
|
|
ges_timeline_parse_launch_effect_new (const gchar * video_bin_description,
|
|
const gchar * audio_bin_description)
|
|
|
|
=> DONE
|
|
|
|
|
|
H - The GESEffect:
|
|
|
|
The GESEffect class is a subclass of GESMaterial, it is used to describe
|
|
effects independently of the usage which is made of it in the timeline.
|
|
|
|
A GESEffect can specify a GESTrackOperation class to use in a
|
|
TimelineObject.
|
|
|
|
All important properties are inherited from GESMaterial such as:
|
|
* Name
|
|
* Description
|
|
* Tags
|
|
* ...
|
|
|
|
We should also be able to list properties of the effect from the GESMaterial.
|
|
|
|
=> Waiting for GESMaterial
|
|
|
|
=================
|
|
TODO GESRegistry API:
|
|
This should be a singleton since we don't want an app to instanciate more
|
|
than one registry. It must be able to get effects from various sources.
|
|
We should also make sure any custom effect is detected.
|
|
|
|
/**
|
|
* ges_registry_get_default:
|
|
*
|
|
* Returns a newly created #GESEffectRegistry or the existing one
|
|
* increasing
|
|
* its refcount
|
|
*/
|
|
GESEffectRegistry *
|
|
ges_registry_get_default (void);
|
|
-> Usecases:
|
|
+ Have a registry of all effects that are on the system (UC-8)
|
|
|
|
/**
|
|
* ges_effect_registry_get_effect_list:
|
|
*
|
|
* @self: The origin #GESEffectRegistry
|
|
*
|
|
* Returns a #GList of #GESEffectDescriptors. The
|
|
*/
|
|
GList *
|
|
ges_registry_get_effect_list (GESEffectRegistry *self);
|
|
-> Usecases:
|
|
+ Get all effects descriptors that are on the system (UC-8)
|