Grass Valley K2 Edge Protocol Manual v1.0 - Manual (Page 12)

K2 Edge Protocol Manual – document version 1.0 – Page 12
4.5. The role field
The NRE command supports the concept of initiator roles, where different roles have different
responsibilities and privileges. At the moment the following roles are recognized:
role description
schedule
(default)
The schedule role represents the single initiator generating NRE commands on behalf of
the programmed (planned) schedule.
realtime The realtime role represents an optional initiator producing real-time (non-planned, ad
hoc) NRE commands.
4.5.1. The schedule role
These are the characteristics of the schedule role:
• No more than one initiator can assume the schedule role.
• The single initiator acting in the schedule role is responsible for implementing the planned playout
schedule. Only the schedule role is allowed to preload- and select scene graphs.
• The schedule role initiator has the responsibility (and knowledge) to carefully plan a scene graph
switch, and the nexos will perform the switch exactly as instructed. Note that the switch will
forcedly stop every running template in the scene graph that is about to be replaced, including
templates triggered by the realtime role initiator.
4.5.2. The realtime role
These are the characteristics of the realtime role:
• Zero or more initiators can assume the realtime role.
• An initiator acting in the realtime role will typically trigger additional templates that normally
should not interfere with the scheduled templates.
• The templates made available for realtime initiators are explicitly marked as safe for realtime use
by the channel designer.
• The realtime role is not allowed to control scene graph switching, and all relevant sub commands
and fields will be ignored.
• Commands issued by a realtime initiator will always be executed as soon as possible and the stm
and stm-play fields will be ignored.
• Commands issued by a realtime role will always be rendered in the currently active scene graph,
even if the scene graph is due for a switch in the near future.
• Commands issued by a realtime role may be aborted while running, or not even be executed at
all as a result of scene graph switching dictated by schedule role commands.
Example:
To specify a role, a command initiator must define the role field in the NRE command. When the role
field is not found, the schedule role is assumed.
{cmd=nre; subcmd=preload; template=ShowLogo; role=realtime; }