LFO – A Graph-based Modular Approach to the Processing of Data Streams

Abstract

This paper introduces lfo — for Low Frequency Operators — a graph-based Javascript (ES2015) API for online and online processing (i.e. analysis and transformation) of data streams such as audio and motion sensor data. The library is open-source and entirely based on web standards. The project aims at creating an ecosystem consisting of platform-independent stream operator modules such as filters and extractors as well as platform-specific source and sink modules such as audio i/o, motion sensor inputs, and file access. The modular approach of the API allows for using the library in virtually any Javascript environment. A first set of operators as well as basic source and sink modules for web browsers and Node.js are included in the distribu- tion of the library. The paper introduces the underlying concepts, describes the implementation of the API, and reports on benchmarks of a set of operators. It concludes with the presentation of a set of example applications.