Everything but the one important thing works now...

#!/usr/bin/python3

from os import path

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

#For threading support
from gi.repository import GObject

GObject.threads_init()

#For the as of this moment not working video...
from gi.repository import Gst, Gtk
# Needed for window.get_xid(), xvimagesink.set_window_handle(), respectively:
from gi.repository import GdkX11, GstVideo

#for keypresses
from gi.repository import Gdk

#for resize
import Xlib
import Xlib.display


Gst.init(None)

class Player(object):
    def __init__(self):
        self.resolution = Xlib.display.Display().screen().root.get_geometry()
        width = 800
        height = 450
        self.win = Gtk.Window()
        self.win.connect('destroy', self.quit)
        self.win.set_default_size(width, height)
        self.win.set_decorated(False)
        self.win.set_keep_above(True)
        self.win.set_property('skip-taskbar-hint', True)

        self.drawingarea = Gtk.DrawingArea()
        self.win.add(self.drawingarea)

        # Create GStreamer pipeline
        print('Getting pipe')
        self.pipeline = Gst.parse_launch ("v4l2src ! autovideosink")
        #self.pipeline = Gst.parse_launch ("v4l2src ! videoconvert ! xvimagesink")

        # Create bus to get events from GStreamer pipeline
        print('Getting bus')
        self.bus = self.pipeline.get_bus()
        self.bus.add_signal_watch()
        self.bus.connect('message::eos', self.on_eos)
        self.bus.connect('message::error', self.on_error)

        # This is needed to make the video output in our DrawingArea:
        self.bus.enable_sync_message_emission()
        self.bus.connect('sync-message::element', self.on_sync_message)

        self.win.connect("key-press-event", self.on_keypress)
        self.on_keypress_dict = {
            Gdk.KEY_Escape : Gtk.main_quit,
            Gdk.KEY_F1 : self.pipeline.set_state,
            Gdk.KEY_F2 : self.pipeline.set_state,
        }
        self.state_args = {
            Gdk.KEY_Escape : Gtk.main_quit,
            Gdk.KEY_F1 : Gst.State.PLAYING,
            Gdk.KEY_F2 : Gst.State.NULL
        }
        self.win.move(self.resolution.width - width, self.resolution.height - height)

    def on_keypress(self, widget, event):
        '''
        A case switch statement to eliminate the
        five checks kludginess
        '''
        print('In keypress')
        if event.keyval == Gdk.KEY_F5: self.properties(widget, event)
        else: self.on_keypress_dict[event.keyval](self.state_args[event.keyval])

    def properties(self, widget, event) :
        self.prop_win = Gtk.Window(Gtk.WindowType.TOPLEVEL)
        self.prop_win.set_title("Properties")
        self.prop_win.set_size_request(320, 120)
        self.prop_win.set_resizable(False)
        self.prop_win.set_keep_above(True)
        self.prop_win.set_property('skip-taskbar-hint', True)
        self.win.connect("destroy", self.closeproperties)
        vbox = Gtk.VBox(spacing=4)
        hbox = Gtk.HBox(spacing=4)
        hbox2 = Gtk.HBox(spacing=4)
        check = Gtk.CheckButton("Pin")
        check.set_active(True)
        check.set_size_request(100, 35)
        check.connect("clicked", self.pinning)
        hbox.pack_start(check, True, True, 0)
        scale = Gtk.HScale()
        scale.set_range(0, 100)
        scale.set_value(100)
        scale.set_size_request(320, 35)
        scale.connect("value-changed", self.opac_slider)
        hbox.pack_start(scale, True, True, 0)
        self.entry = Gtk.Entry()
        self.entry2 = Gtk.Entry()
        self.entry.set_text("width")
        self.entry2.set_text("height")
        hbox2.pack_start(self.entry, True, True, 0)
        hbox2.pack_start(self.entry2, True, True, 0)
        hbox3 = Gtk.HBox(spacing=4)
        ok = Gtk.Button("OK")
        ok.connect("clicked", self.change_size)
        hbox3.pack_start(ok, True, True, 0)
        exit = Gtk.Button("Exit")
        exit.connect("clicked", self.closeproperties)
        hbox3.pack_start(exit, True, True, 0)
        vbox.pack_start(hbox, True, True, 0)
        vbox.pack_start(hbox2, True, True, 0)
        vbox.pack_start(hbox3, True, True, 0)
        self.prop_win.add(vbox)
        self.prop_win.show_all()

    def pinning(self, checkbox):
        if checkbox.get_active():
            self.set_keep_above(True)
        else:
            self.set_keep_above(False)

    def opac_slider(self, w):
        self.win.set_opacity(w.get_value()/100.0)

    def change_size(self, w):
        print('in change size')
        width = int(self.entry.get_text())
        height = int(self.entry2.get_text())
        self.win.resize(width,height)
        self.win.move(self.resolution.width - width, self.resolution.height - height)
        self.win.show_all()

    def closeproperties(self, w):
        self.prop_win.hide()

    def run(self):
        self.win.show_all()
        # You need to get the XID after window.show_all().  You shouldn't get it
        # in the on_sync_message() handler because threading issues will cause
        # segfaults there.
        self.xid = self.drawingarea.get_property('window').get_xid()

        print('in get_xid')
        self.pipeline.set_state(Gst.State.READY)
        Gtk.main()

    def quit(self, window):
        self.pipeline.set_state(Gst.State.NULL)
        Gtk.main_quit()

    def on_sync_message(self, bus, msg):
        if msg.get_structure().get_name() == 'prepare-window-handle':
            print('prepare-window-handle')
            msg.src.set_window_handle(self.xid)
            print('prepped')

    def on_eos(self, bus, msg):
        print('on_eos(): seeking to start of video')
        self.pipeline.seek_simple(
            Gst.Format.TIME,
            Gst.SeekFlags.FLUSH | Gst.SeekFlags.KEY_UNIT,
            0
        )

    def on_error(self, bus, msg):
        print('on_error():', msg.parse_error())


p = Player()
p.run()