ONVIF Profile G involves multiple protocols.
ONVIF Profile G involves multiple protocols thought there is only one specification document for Profile G
For recording: recording search specification and its corresponding WSDL, recording control and its corresponding WSDL.
For replay: replay control specification and its corresponding WSDL. The section "6 Playback" of streaming specification is also highly relevant.
A camera must have at least one RecordingJob to start recording.