How is mass converted to gravitational wave energy by inward spiralling binary black holes?

Energy Conversion from Mass to Gravitational Wave
Is the gravitational wave energy coming purely from the kinetic energy/gravitational potential of the two black holes? Or does the merged black hole emit mass beyond that?

Energy Conversion from Mass to Gravitational Wave

Is the gravitational wave energy coming purely from the kinetic energy/gravitational potential of the two black holes? Or does the merged black hole emit mass beyond that?