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design: fixe effects API after Edward review

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Thibault Saunier 2011-01-21 10:43:09 +01:00 committed by Edward Hervey
parent b659f8902b
commit 9df758aeb6
1 changed files with 55 additions and 60 deletions
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113
docs/design/effects.txt
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@ -29,8 +29,8 @@ API which would allow developers to handle any use-cases.
* 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
* 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
@ -38,12 +38,8 @@ API which would allow developers to handle any use-cases.
* 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 and
not directly configuring the corresponding GstElement properties.
==> EDWARD : The wording makes it a bit confusing. Here one could
read that we'll be offering an API to get/change properties
which is completely different from the standard GObject API.
* 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.
@ -73,7 +69,8 @@ B. Effects configurability
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
We should also find a way to handle that in the case of systems such as
gnome-effects
C. Keyframes
@ -84,31 +81,32 @@ C. Keyframes
4. Use-cases
-----------
UC-1. The user wants to add an effect to an entire clip => GESTimelineObject new API
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 special portion of a clip, we should
allow him to configure that thanks to a system of keyframes. FIXME
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.
==> EDWARD : Just change the in-point/duration/start of that
effect within the TrackObject. See the mapping document and
feature within GESTimelineObject.
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-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-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
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
UC-7. Developers want to expose all effects present on the system to the
end-user
5. API draft
------------
@ -118,35 +116,27 @@ C. Keyframes
signals:
-------
* property-changed: emited when a property of the GESTrackObject gst element
is changed
==> EDWARD : So this would be exactly the same signal as
GObject's 'notify' ? Or at least it's very similar to
GstObject's deep-notify feature. Might want to look into
that (not for using it, but for how it's implemented).
Same comment about the set/get properties. Maybe the
GstChildProxy interface would be worth a look also.
* property-changed: emited when a usefull property of a GstElement
contained in the GESTrackObject changes
/**
* ges_track_object_list_gst_properties:
* ges_track_object_list_children_properties:
*
* @object: The origin #GESTrackObject
*
* Get all the usefull configurable properties of the GstElement contained in @object.
* Get all the usefull configurable properties of the GstElement contained
* in @object.
*
* Returns: an array of GParamSpec of the configurable properties of the
* GstElement-s contained in @object
*/
GParamSpec **
ges_track_object_list_gst_properties (GESTrackObject *object);
ges_track_object_list_children_properties (GESTrackObject *object);
-> Usecases: Let user know all the property he can configure.
/**
* ges_track_object_set_gst_property:
* ges_track_object_set_child_property:
*
* @object: The origin #GESTrackObject
* @property_name: The name of the property
@ -155,14 +145,14 @@ C. Keyframes
* Sets a property of a GstElement contained in @object.
*
*/
void ges_track_object_set_gst_property (GESTrackObject *object,
void ges_track_object_set_child_property (GESTrackObject *object,
const gchar *property_name,
GValue * value);
-> Usecases:
+ Let user configure effects easily (UC-3)
/**
* ges_track_object_get_gst_property:
* ges_track_object_get_child_property:
*
* @object: The origin #GESTrackObject
* @property_name: The name of the property
@ -170,7 +160,7 @@ C. Keyframes
*
* Gets a property of a GstElement contained in @object.
*/
void ges_track_object_get_gst_property (GESTrackObject *object,
void ges_track_object_get_child_property (GESTrackObject *object,
const gchar *property_name,
GValue * value);
@ -180,9 +170,7 @@ C. Keyframes
-------
* effect-added: emited when an effect is added
* effect-removed: emited when an effect is removed
* effect-moved: emited when an effect is moved
==> EDWARD : What do you mean by 'moved' ?
* effect-priority-changed: emited when an effect priority-changed
/**
* ges_timeline_object_add_effect:
@ -194,11 +182,12 @@ C. Keyframes
*
* Adds a new effect corresponding to @material to the #GESTimelineObject
*
* Returns: The newly created #GESTrackEffect, or %NULL if there was an error.
* Returns: The newly created #GESTrackEffect, or %NULL if there was an
* error.
*/
GESTrackEffect *ges_timeline_object_add_effect (GESTimelineObject *object,
GESMaterial *effect_material,
gint position);
GESMaterial *effect_material,
gint position);
/**
* ges_timeline_object_get_effects:
@ -237,30 +226,35 @@ C. Keyframes
*
* Creates a new #GESTrackEffect from a #GESMaterial
*
* Returns: a newly created #GESTrackEffect, or %NULL if something went wrong.
* Returns: a newly created #GESTrackEffect, or %NULL if something went
* wrong.
*/
GESTrackEffect *ges_track_effect_new_from_material(GESTrackEffect *effect, GESMaterial *material);
GESTrackEffect *ges_track_effect_new_from_material(GESTrackEffect *effect,
GESMaterial *material);
/**
* ges_track_effect_new_from_bin_desc:
*
* @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.
* 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.
* Returns: a newly created #GESTrackEffect, or %NULL if something went
* wrong.
*/
GESTrackEffect *ges_track_effect_new_from_bin_desc(GESTrackEffect *effect,
const gchar *bin_desc);
D - The GESTimelineEffect API:
The GESTimelineEffect basically doesn't have anything else but what GESTimelineObject has.
The GESTimelineEffect basically doesn't have anything else but what
GESTimelineObject has.
-> 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 about what clip it is applied on.
-> 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.
=================
TODO GESRegistry API:
@ -271,7 +265,8 @@ C. Keyframes
/**
* ges_registry_get_default:
*
* Returns a newly created #GESEffectRegistry or the existing one increasing
* Returns a newly created #GESEffectRegistry or the existing one
* increasing
* its refcount
*/
GESEffectRegistry *