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import datetime
import threading
import traceback

import gi

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

from gi.repository import Gst, GObject, GLib


def debug(*args) -> None:
    print(datetime.datetime.now().time().isoformat(), threading.current_thread().name, *args)


# doesnt work
mipi_camera = '''nvarguscamerasrc name=front do-timestamp=true silent=false
    ! video/x-raw(memory:NVMM), width=(int)1280, height=(int)720, format=(string)NV12, framerate=30/1 
    ! nvvidconv
    ! queue
'''

# works
usb_camera = '''
v4l2src device=/dev/video1 do-timestamp=true name=front 
    ! image/jpeg,width=1280,height=720,framerate=30/1 
    ! jpegdec 
    ! videoconvert 
    ! nvvidconv
    ! queue
'''

pipeline_desc = f'''
nvcompositor name=comp 
    sink_0::xpos=0 sink_0::ypos=0 sink_0::width=1280 sink_0::height=1080 
    sink_1::xpos=0 sink_1::ypos=0 sink_1::width=1280 sink_1::height=720 

    videotestsrc is-live=true do-timestamp=true name=background ! 
        video/x-raw,width=320,height=180,framerate=30/1 ! 
        nvvidconv !
        comp.sink_0 
    comp. ! nvegltransform ! nveglglessink
'''

# works
camera_desc = usb_camera

# doesnt work
camera_desc = mipi_camera

Gst.init(None)

pipe = Gst.parse_launch(pipeline_desc)
bus = pipe.get_bus()

comp = pipe.get_by_name('comp')


def _pad_added(element, pad):
    debug('_pad_added', element.name, pad.name)

    srcbin = Gst.parse_bin_from_description(camera_desc, True)
    static_pad = srcbin.get_static_pad('src')
    pipe.add(srcbin)
    pipe.sync_children_states()
    static_pad.link(pad)


comp.connect('pad-added', _pad_added)
pipe.set_state(Gst.State.PLAYING)


def connect_front():
    debug("connecting front camera")
    comp.get_request_pad('sink_1')


gloop = GObject.MainLoop()
GLib.timeout_add(3000, connect_front)
try:
    gloop.run()
except:
    traceback.print_exc()
    pipe.send_event(Gst.Event.new_eos())
    keep_polling = True
    while keep_polling:
        message = bus.poll(Gst.MessageType.ANY, 1005000000)
        debug(message)
        keep_polling = message is not None

    pipe.set_state(Gst.State.NULL)