ONELAN | Support

AdvanceTo and Change Layout Mechamisms

Overview

This document describes the functionality and usage of the NTB’s AdvanceTo and Change Layout mechanisms. These mechanisms have been in the NTB software since 2006 and are used as building blocks for other facilities such as touch and RS232 input lines, as introduced at the V6.2 level in Q4 of 2008

Change Layout

A NTB drives an LCD display with an multi-Zone, multi-Media image. The overall image is called a Layout. Layouts can be Scheduled to run at user defined times-of-day and day-of-week. However, Layouts may also be changed by commands embedded within the PlayLists associated with Zone(s) defined within the current Layout. These commands are called "Change Layout" commands.

AdvanceTo and Rendezvous mechanism

The NTB can be configured to alter the currently playing media by jumping around PlayLists in response to events. The position within a PlayList that is jumped to, is called a Rendezvous Point. Rendezvous Points have a unique name.

There are a number of mechanisms provided to issue the command to move to said Rendezvous point. They include:

An AdvanceTo command executed in any currently playing PlayList (including its own PlayList).
An AdvanceTo command delivered over the NTBs Ethernet port in the form of an XML message ‘posted’ to the HTML TCP port.
Transitions of binary input lines (delivered via the RS232 port, V6.2 onwards). These events can be configured to create AdvanceTo commands.
Touch events derived from an attached touch sensitive overlay panel – V6.2 onwards.

Any Playlist that receives an AdvanceTo, interrupts the media it is currently playing and re-starts the Playlist at the media item following the Rendezvous point identified by its name.

A given Layout can have any number of Rendezvous (or AdvanceTo commands) as part of the set of PlayList associated with their respective Zones. The Rendezvous names are variable length strings so there is no limit to their number.

Both Change Layout and AdvanceTo can cause changes to the media being played by the NTB. The main difference is that a Change Layout collapses the entire running Layout and starts a new one – possibly with radically different geometry for the Zones. This may lead to an undesirable screen flicker. An AdvanceTo generally causes ‘finer grained’ changes to playing media without the need for a Layout change.