The GNL API changed to go from a model where user could
enable/disable updates in the composition, which leaded to races
in many places, to a model where any positioning change in the
composition is not directly done but 'cached' and then the user
has to commit those changes so they become effective in the media
processing stack.
The new API in GES is pretty similare and is basically copy
pasting this new design.
We still need to see if in some context it would make sense to add
a mode where we would commit any changes ourself at the end of our
operation for basic use cases.
Removed APIs:
ges_timeline_enable_update
ges_timeline_is_updating
ges_track_enable_update
ges_track_is_updating
New APIs:
ges_track_commit
ges_timeline_commit
ges_timeline_append_layer now creates a new layer, adds it to the timeline
and returns it
This code has not been released yet so we can break this API.
This will give us margin for API expansion without breaking ABI.
The ABI restriction will only come in place once we do the first
official release (i.e. 0.x.0).
If a GESTimelineFileSource is added to a layer and:
* It doesn't have specified supported formats
* OR it doesn't have a specified maximum duration
* OR it doesn't have a specifed duration
Then we asynchronously send it to the GstDiscoverer.
If this happens, the state change of the timeline from READY to
PAUSED will happen asynchronously and be completed when everything
has been properly discovered.
Part 2 of GstDiscoverer integration
