It's not part of the API, let's make this a bit more obvious by a prefix.

Add some biquad filters to the builtin filters.
Add an example 6 band equalizer sink filter chain.

When we manually acquire buffers from the pool, we never release them.
But because gst_buffer_pool_acquire_buffer() adds a reference to the pool,
this leaks the pool eventually.

To fix this, just unref the buffer after it has been sent. This releases
it back to the pool and unrefs the pool.

This has no significant effect to the stream, since the underlying
pw buffers are actually pooled in the pw_stream. It just prevents leaking.

When pipewiresink needs to copy data, it has to resize the destination
buffer (to a smaller size) in order to send the correct data size to
pipewire. When this dest buffer is reused later, it will still have
this smaller size as its total size and the copy may discard data
from upstream if the new upstream buffer is bigger than the last one
that was copied on the same dest buffer.

The filter properties are on the input stream.

Is more convenient for custom properties without an id.

Some properties can be part of a params field in the Props object
and contain the string key and the pod value to be configured. This
is easier to use than using the regular id.

Add the fact that the property is also part of params in the PropInfo.

To make an rnnoise filtered source:

pactl load-module module-ladspa-source source_name=rnnoise_mic label=noise_suppressor_mono plugin=/usr/lib64/ladspa/ladspa/librnnoise_ladspa.so

To make an equalizer sink:

pactl load-module module-ladspa-sink sink_name=eq_out label=mbeq plugin=/usr/lib64/ladspa/mbeq_1197.so

Add a simple mixer builtin plugin.
Free memory on module unload.

Add support for getting the control ports from a node. Use this to
configure the control port values.

run with pipewire -c filter-chain/demonic.conf

Address controls with node_name:port_name to access all properties
in the graph.

When inputs/outputs are specified, find the node:port and link them.
Fall back to the first/last node for input/output if no node is given.
Fall back to all input/output ports when no ports are given.

This does not have to be ladspa specific so rename it.

Expand the syntax to allow a graph of nodes and links later.

Use custom keys and propinfo to map the name to the key. This allows
us to specify ranges and other context for the properties.

Parse initial control values
Reset to default when value is null
Implement port selection by name.

Run multiple instances to fill requested channels.
Improve media name.

Can be used to build chains or sink/source.

Reset the software volume when initializing the device and when the
hardware volume is updated.

The software volume was set to 0 by default and if the session manager
did not change the volume enough to cause a software volume change,
it would remain 0 and there would be silence.

Also improve the debug a little.

See #1160 #1167 #1164 #1049 #1117