Does deepstream gst-nvstreamux uses ntp timestamp for multiple input streams synchronization?

In deepstream gst-nvstreammux the sync-inputs property inside the property table is defined as “Boolean property to sychronization of input frames using PTS”.

https://docs.nvidia.com/metropolis/deepstream/dev-guide/text/DS_plugin_gst-nvstreammux.html

and in the new streammux documentation, it defines it as "Synchronize Inputs. Boolean property to force timestamp sychronization of input frames.".

https://docs.nvidia.com/metropolis/deepstream/dev-guide/text/DS_plugin_gst-nvstreammux2.html

does the new gst-nvstreammux uses the RTCP NTP timestamp for synchronizing the frames from multiple RTSP streams or the PTS time?

Please provide complete information as applicable to your setup.
• Hardware Platform (Jetson / GPU)
• DeepStream Version
• JetPack Version (valid for Jetson only)
• TensorRT Version
• NVIDIA GPU Driver Version (valid for GPU only)
• Issue Type( questions, new requirements, bugs)
• How to reproduce the issue ? (This is for bugs. Including which sample app is using, the configuration files content, the command line used and other details for reproducing)
• Requirement details( This is for new requirement. Including the module name-for which plugin or for which sample application, the function description)