Vidyo AMX and Crestron Modules

Vidyo was referred to my company by a Crestron representative when they were looking to build a custom control module for integrating with their VidyoRoom line of dedicated codecs. Vidyo was happy to learn that we also provide AMX programming support, and so we set out to build both the AMX and Crestron modules that Vidyo would offer as standard for their products.

As with most projects, the most challenging part of this project was communication. We initially failed to understand their needs and also failed to communicate the timeline we anticipated. Much of the project was spent recovering from this mishap and rebuilding trust with Vidyo, while trying to negotiate a reasonable delivery criteria we each could agree upon. Fortunately, we met this goal and continued to build our relationship with Vidyo.

In terms of technical challenges, Vidyo needed a fairly straightforward conversion of their on-screen interface into the example programs shipping with the modules. Their on-screen interface had access to a wealth of internal state data and queries that the API didn’t yet offer, so we coordinated on improving the API with Vidyo to make these tools available. In addition, their UI included some patterns that we hadn’t yet implemented in the AMX or Crestron spaces. One particular example:

  1. User enters a string on touchpanel
  2. The controller calls a Vidyo API to determine what types of results are returned when this string is searched for on their portal
  3. When the results are returned, a further API call is made to determine the state of the endpoint in some conditions
  4. Finally accumulating the information, the correct API command can be issued to initiate the video session.

While this type of interaction would be simple and near-instant with modern programming (for example, making an SQL query or firing a library call) particularly with blocking calls while this processing occurs, Crestron and AMX have no such benefit. Neither system offers a blocking call per se, all inputs and outputs are asynchronous. As such, there is a lot of complex state maintenance in that code to understand what the results actually mean when they are returned. The AMX module in particular adds quite a lot of context information back to the main program when this type of exchange occurs, taking that burden off of the programmer.

The AMX module on and the Crestron module on Crestron’s Application Market are the modules I developed and published during my time with Advanced Control Systems. The documentation was also produced by myself and my coworker Steve.

Technologies: AMX; Crestron; RS232/Serial; TCP/IP