node-visca

(( THIS CODE IS IN DEVELOPMENT AND IS UNTESTED ))

Description

This is a complete implementation of the Sony VISCA Protocol for the EVI-H100s and similar cameras. It also contains commands to implement the additional features from PTZOptics and LUMiO12x cameras. The library assumes you know which commands will work on your cameras, but don't worry; commands not recognized by your camera will simply be ignored.

Installation

From inside your project directory...

npm i @utopian/visca --save

Usage

Rationale...

Of course, the main reason for this module is to fully implement the VISCA protocol without any reliance on libvisca the main C library for VISCA commands.

I did it as a challenge to myself, but also so that the VISCA protocol could be more easily understood by Javascript/Typescript developers who are not comfortable reading protocol documentation or C source code.

Finally, by implementing it in Typescript, I have been able to create a code-base that can be parsed easily by Visual Studio Code (and presumably other IDEs) providing intelligent code suggestions to make calling VISCA commands much easier on the developer.

The biggest challenge for the Javascript/Typescript ecosystem in managing Visca connections is that Visca commands are intended to be executed in the following manner:

• send a command over the serial or network connection
• wait for an ACK (for most commands)
• wait for a DONE (for many commands)

Javascript doesn't like to work this way. Javascript/Typescript code wants everything to run asynchronously, so this library virtualizes VISCA cameras to maintain command buffers and callbacks. As VISCA commands come in, the Camera objects will update themselves and then emit an 'update' event. As a developer, you only need to send commands and listen for changes on the various objects.