test2.py

from kivy.lang import Builder
from kivy.app import runTouchApp
from kivy.clock import Clock

kv = '''
VideoGrid

<VideoGrid@BoxLayout>:
    source: r'G:\\Python\\dev2\\kivy27\\examples\\widgets\\softboy.mpg'
    state: 'stop'

    tiled: False

    Video:
        source: root.source
        state: root.state

        opacity: 0 if root.tiled else 1

    GridLayout:
        cols: 4
        rows: 4


        Video:
            source: root.source
            state: root.state

        Video:
            source: root.source
            state: root.state


        Video:
            source: root.source
            state: root.state


        Video:
            source: root.source
            state: root.state

        Video:
            source: root.source
            state: root.state

        Video:
            source: root.source
            state: root.state

        Video:
            source: root.source
            state: root.state

        Video:
            source: root.source
            state: root.state

        Video:
            source: root.source
            state: root.state

        Video:
            source: root.source
            state: root.state

        Video:
            source: root.source
            state: root.state

        Video:
            source: root.source
            state: root.state'''

root = Builder.load_string(kv)
Clock.schedule_once(lambda dt: root.setter('state')(root, 'play'), 5)
runTouchApp(root)