Using the command line, it can be displayed normally.
The command line is as follows.
gst-launch-1.0 -e rtspsrc location=rtsp://192.168.0.35/stream0 ! rtph265depay ! h265parse ! omxh265dec ! nvvidconv ! nvcompositor ! nvoverlaysink sync=false
The code implementation of almost the same pipeline cannot be displayed normally.
Part of the code is as follows.
strgst = '''nvcompositor name=comp
sink_0::xpos=0 sink_0::ypos=0 sink_0::width=400 sink_0::height=400
sink_1::xpos=1820 sink_1::ypos=580 sink_1::width=100 sink_1::height=100
! nvoverlaysink name=viewsink sync=false overlay-x=0 overlay-y=400 overlay-w=1920 overlay-h=680 videotestsrc
! nvvidconv
! comp.sink_1
'''
pipeline = Gst.parse_launch(strgst)
comp = pipeline.get_by_name("comp")
pipeline.set_state(Gst.State.PLAYING)
pipestring = '''rtspsrc location=rtsp://rtsp://192.168.0.35/stream0 ! rtph265depay ! h265parse ! omxh265dec ! nvvidconv '''
srcbin = Gst.parse_bin_from_description(pipestr, True)
pipeline.add(srcbin)
comp_sink_pad = comp.get_request_pad("sink_0")
comp_sink_pad.set_property("xpos",0)
comp_sink_pad.set_property("ypos",0)
comp_sink_pad.set_property("width",400)
comp_sink_pad.set_property("height",400)
pipeline.sync_children_states()
srcbin.get_static_pad("src").link(comp_sink_pad)