Create a video with frame number and timestamp overlayed.

timestamp_overlay_video.py

#!/usr/bin/env python3

import gi

gi.require_version('Gst', '1.0')
gi.require_version('GLib', '2.0')

from gi.repository import Gst, GLib

FILE="/tmp/test.mp4"

def main():
    Gst.init ()

    pipe = Gst.parse_launch ("videotestsrc ! identity name=i ! video/x-raw,width=1920,height=1080 ! textoverlay halignment=center name=overlay ! queue ! x264enc ! qtmux ! filesink location=%s"%FILE)

    overlay = pipe.get_by_name ("overlay")
    identity = pipe.get_by_name ("i")

    # Change overlay with each buffer's info
    identity.connect("handoff",
                     lambda elem, buf:
                     overlay.set_property("text", "offset: %d, offset-end: %d, dts: %d, pts: %d"%(buf.offset, buf.offset_end, buf.pts, buf.dts)))
    pipe.set_state (Gst.State.PLAYING);

    loop = GLib.MainLoop()
    try:
        print("Running, ctrl+c to stop...")
        loop.run()
    except:
        print("Closing...")
        loop.quit()

    # And EOS is needed to write the MP4 headers and have a playable files
    pipe.send_event(Gst.Event.new_eos())
    pipe.get_bus().timed_pop_filtered(15000000000, Gst.MessageType.EOS)
    pipe.set_state (Gst.State.NULL);

    Gst.deinit()

if __name__ == "__main__":
    main()