Implement lazy loading asset cache so gesdemux use the formatters
assets while GES hasn't been initialized.
And set extensions to temporary files as some formatters require
the information (otio)
Uses the file extension as hint falling back to the default formatter
if none is found
Make use of that function in when saving a project and not formatter
is specified.
This method is useful when implementing a formatter outside
GES that end up converting to xges and uses the default formatter
to finally load the timeline.
Adding a property to let the application know
Also make sure that the duration of nested timeline assets is reported
as CLOCK_TIME_NONE as those are extended as necessary.
And make a difference between asset duration and their max duration
As nested timelines can be extended 'infinitely' those max duration
is GST_CLOCK_TIME_NONE, but their duration is the real duration of
the timeline.
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
Make sure that an event resulting from the seek happens before removing
the pad probe, dropping anything while it is not the case.
This guarantees that the seek happens before `nlesource` outputs
anything. This was not necessary as with decodebin or usual source
flushing seeks lead to synchronous flush_start/flush_stop and we could
safely assume that once the seek is sent, it was happenning.
With nested `nlecomposition` this assumption is simply not true as
in the composition seeks are basically cached and happen later in
the composition updating thread.
This fixes races where we ended up removing the blocking probe before
the seek actually started to be executed in the nlecomposition
nested inside an nlesource which leaded to data from *before* the seek
to be outputed which means we could display wrong frames,
and it was leading to interesting deadlocks.
Seeks that lead to a stack change lead to deactivating the current
stack. At that point we explicitely flush downstream as a reaction to
the flushing seek. Until now those flushes had a random seqnum, this
fails if we are a nested compostion as the parent composition will end
up dropping that flush which in turns might lead to deadlocks. For
example, the flush goes through a `compositor` which wants to flush
downstream to stop its srcpad task, but that flush wouldn't have
"released" its srcpad thread if the composition srcpad drops it, meaning
it won't be able to stop the task ever.
Otherwise if we shutdown a composition whith an nested composition
(inside a source in the test) and leak it, we end up with the nested
composition task still running (in READY) which is bad.
Add a test for that which leaks the pipeline on purpose.
