This paper presents an open source computational tool framework for the visualization and analysis of signals with timedependent spectral content. SIRLAB (SIgnal Representation LABoratory) is the name given to this tool framework, written in C-language for a Linux environment and using the OpenCV (Open Source Computer Vision) platform, a software library of programming functions for near-real-time computer vision application development. SIRLAB was initially developed as an application tool kit for environmental surveillance operations pertaining to acoustic monitoring of birds, amphibians, and aquatic animals. In this setting, it receives acoustic raw signal-data and it produces ordered sets of spectrogram frames which may be presented in a streaming video format due to its fast computation. Computer speed ups of more than 30 times have been reached when compared with MATLAB implementations utilizing the same computational resources and algorithm formulations. This allows to produce streaming video with a frame rate of 30 frames per second, for some applications, reaching the ATSC digital television frame rate standard.