When we have nested timelines, we need to make sure the underlying
formatted file is reloaded when commiting the main composition to
take into account the new timeline.
In other to make the implementation as simple as possible we make
sure that whenever the toplevel composition is commited, the decodebin
holding the gesdemux is torn down so that a new demuxer is created
with the new content of the timeline.
To do that a we do a NleCompositionQueryNeedsTearDown query to which
gesdemux answers leading to a full nlecomposition stack
deactivation/activation cycle.
It was making no sense to consider it an empty timeline when the user
had passed the project URI when requesting the asset. Usually user
use `ges_project_new` with the URI but it is also valid to use
`ges_asset_request` with the uri as ID so let's handle that properly.
Subprojects simply consist of adding the GESProject
to the main project asset list. Then those are recursively
serialized in the main project in the <asset> not, when deserializing,
temporary files are created and those will be used in clips
as necessary
Making sure to have 1 GstDiscoverer per thread.
Use that new feature in gesdemux by loading the timeline directly from
the streaming thread. Modifying the timeline is not supported allowed
anyway.
In the case of nested timeline in the toplevel timeline we ended up
with CompositionUpdate for seeks sent by our own composition to
granchildren composition. This was not causing essential issues
if all tracks where containing nested timelines but in cases
where one of the tracks only had a nested timelines, then we
were waiting forever for a `CompositionUpdateDone`.
CompositionUpdate translated into ASYNC_START/ASYNC_DONE should
be kept inside the GESTimeline and not travel up (possibly to some
parent GESTimeline).
For smptealph element to work as expected the following compositing
element should mix with the default "over" operator, as described
in its documentation.
Setters return values should return %FALSE **only** when the value
could not be set, not when unchanged or when the subclass handled
it itself!
This patches makes it so the return value is meaningul by allowing
subclasses return anything different than `TRUE` or `FALSE` (convention
is -1) to let the subclass now that it took care of everything and
no signal should be emited.
Now that the notion of layer has been moved down to #GESTimelineElement
(through the new #ges_timeline_element_get_layer_priority method), this
method make much more sense directly in the base class.
ges_container_add removes the child being added if the call to
ges_timeline_element_set_parent fails. In this case, subclasses should
be given the chance to revert the effects of the add_child vmethod which
has just been called.
