1.2 Xspect Abstract


X. Rodet & D. François - Analysis/Synthesis Team

Xspect is a program for Visualisation, Analysis and Editing of Sound Signals written in the Analysis/Synthesis team at Ircam. Here is a possible image of Xspect on your console:



Xspect is a visualisation and analysis tool aimed at helping processing and synthesis or genarally any musical and scientific work on sound signals. It is written in Xwindow/Motif to be portable on Unix workstations (already ported on SGI and Alpha platforms) and be usable across a network. Signals from sound files or produced by analysis routines such as FFT or Fundamental Frequency are contained in Buffers. Xspect tries to manipulate files and buffers "a la" Emacs (in the limits of the analogy). Using memory mapping, Xspect accepts signals of any size, only limited by disk space. Xspect opens Windows on the user's display. Windows can be arbitrarily cut horizontally and/or vertically into Frames and SubFrames (to easily compare files, look at multiple channels, have a spectrum close by a signal etc.). In each frame one or several Views can be superposed just like transparencies where the signals are traced. Views provide multiple cursors and selections with a label and a currently active selection or cursor. Xspect can also load, edit, manipulate and display Breakpoint-Functions in a view to be used as envelopes for instance. Xspect allows an automatic Synchronisation of actions between multiple views: For instance the movement of a cursor can force the refresh of another view and/or a new analysis in yet another view. Xspect offers many facilities to adjust precisely displays, analysis, zooming, panning etc. in any details independently in any view.

For sound file input, Xspect now uses the Audio File Library. Therefore all the format supported by this library are available. In particular, Ircam's sound file format is fully supported, short, float, and from any big/little endian machine. Usual AIFF and AIFF-C sound files not compressed are also supported, as well as WAV and SND formats. Other sound file formats are accessible through user's definition. Using the network, Xspect can run on any CPU, display on any console (including Macs and PCs running X emulation), and play short and float files on any audio server or X Terminal with audio capabilities. Sound analysis and manipulations can be extended by the user through system calls. Xspect is in use at Ircam since months and is available for outside users. Xspect is also a visualisation server: using the FTS-TCP/IP protocol, it can receive signals produced by other programs over the network, place them in buffers automatically and then display or manipulate them as any other signal. Inversely, it can send signals with the same protocol, such as waveforms, spectrum, envelope, etc.. In this server mode, it is used for instance to help development and tuning of FTS patches.