Get ntp timestamp through rtspsrc

General Discussion
1

If I am sure my camera can send sr packets, can I get ntp time in the future through rtspsrc group?
Below is my pipeline:

    GstElement *src = gst_element_factory_make("rtspsrc", "src");
    GstElement *depay = gst_element_factory_make("rtph265depay", "depay");
    GstElement *parse = gst_element_factory_make("h265parse", "parse");
    GstElement *identity = gst_element_factory_make("identity", "identity");
    GstElement *mux = gst_element_factory_make("mp4mux", "mux");
    GstElement *sink = gst_element_factory_make("splitmuxsink", "sink");
2

Not sure for your case, though you may run in your current install:

gst-inspect-1.0 rtspsrc

and you may give a try to property ntp-sync.

Maybe first prototyping with gst-launch-1.0 could help.

3

According to the official statement, add-reference-timestamp-meta was introduced in Gstreamer 1.22. Its description is When syncing to a RFC7273 clock, add #GstReferenceTimestampMeta to buffers with the original reconstructed reference clock timestamp. Then I can get the timestamp of the original ntcp sender in GstReferenceTimestampMeta, but I am using Gstreamer1.20, so how can I get the timestamp of the rtcp sender, because I need it to be inserted into the MP4 file as sei