The UmdReceiver class is used to listen for and process UMD packets from the network (typically from devices such as video switchers).

Starting and Stopping

The receiver does not begin communication when first created.

Starting and stopping can be done by calling the and UmdReceiver.close() methods manually


>>> import asyncio
>>> from tslumd import UmdReceiver
>>> async def run():
...     receiver = UmdReceiver()
...     await
...     ...
...     await receiver.close()

or it can be used as an asynchronous context manager in an async with block


>>> import asyncio
>>> from tslumd import UmdReceiver
>>> async def run():
...     receiver = UmdReceiver()
...     async with receiver:
...         ...

Object Access

While running, it will create Screens and Tallies as information for them arrives. Screens are stored in the screens dictionary using their index as keys.

While each Screen object contains its own Tally instances, the Receiver stores all Tally objects from all Screens in its own tallies dictionary by their (TallyKey)


The UmdReceiver.on_screen_added event is used to listen for new Screen objects and the UmdReceiver.on_tally_added is used to listen for new Tally objects (which will be fired for all new Tallies across all Screens).

Like Screens, the Receiver will propagate the on_tally_update event of each Screen and emit its own UmdReceiver.on_tally_updated event. Because of this, one may only need to subscribe to a single event to handle all Tally changes across all Screens


In following example, assume a device is sending tally information for four tallies labeled "Camera 1", "Camera 2", "Camera 3", "Camera 4". They are indexed 1 through 4 and their screen index is 1.


>>> import asyncio
>>> from tslumd import UmdReceiver
>>> def screen_added(screen, **kwargs):
...     print(f'screen_added: {screen!r}')
>>> def tally_added(tally, **kwargs):
...     print(f'tally_added: {tally!r}')
>>> def tally_updated(tally, props_changed, **kwargs):
...     for name in props_changed:
...         value = getattr(tally, name)
...         print(f'tally_updated: {tally!r}.{name} = {value}')
>>> receiver = UmdReceiver()
>>> receiver.bind(
...     on_screen_added=screen_added,
...     on_tally_added=tally_added,
...     on_tally_updated=tally_updated,
... )
>>> async def run():
...     async with receiver:
...         await asyncio.sleep(2)
>>> loop.run_until_complete(run())
screen_added: <Screen: 1>
tally_added: <Tally: ((1, 1) - "Camera 1")>
tally_added: <Tally: ((1, 2) - "Camera 2")>
tally_added: <Tally: ((1, 3) - "Camera 3")>
tally_added: <Tally: ((1, 4) - "Camera 4")>
tally_updated: <Tally: ((1, 1) - "Camera 1")>.rh_tally = RED
tally_updated: <Tally: ((1, 2) - "Camera 2")>.rh_tally = GREEN

When the receiver first opens, the on_screen_added and on_tally_added events are triggered once they are detected.

After a second or so, the tally for “Camera 1” is set to red and “Camera 2” is set to green. Both of these trigger the on_tally_updated event as shown above.