Make explicit links between elements that are used to activate the
next element in the graph.
Make subgraphs a special regular node. Make a link from the
subgraph children to the parent so that the subgraph completes when
all the children completed.
Implement a single process function in plugins
Remove many messages in the client node
Move the activation state to the graph
Replace an old scheduler with a new one that works with the new
activation states.
Remove the DISABLED port flags, we explicitly add and remove to
make ports enabled/disabled.
Find first compatible port for link
Remove the node based scheduler and use the spa one.
Make a new PropInfo parameter that allows us to iterate all
properties. Make some new fields to set labels and names for
properties. We will be able to add more things to describe the
properties this way.
Use the Props param to simply query or set properties.
We can now make int enum properties and describe all possible
values with labels, we don't need to register types anymore.
This then makes it possible to enumerate the v4l2 controls and make
them available as control params.
Reorganize the io parameter ids and objects. Make separate enumerations
for buffer, control, input and output properties.
Add a volume output property to export-source. This is still unused
but will eventually be routed to a PropsIn io area where it can
control the volume of a mixer, for example.
Pass a spa_pod as the control io area. The pod is not supposed to
change in structure, only the values do so we can achieve the same
kind of performance as passing a single value but still allow for
more complex io area layouts to be passed later.
Add control properties to audiotestsrc for frequency and volume
and add a test program.
Add size parameter to set_io for additional checks and to make it
easy to know how much control data we can write.
