Skip to main navigation menu Skip to main content Skip to site footer
FrancoAngeli Journals

Technical notes

Vol. 47 No. 2 (2023)

Colour Enhanced Time/Pressure Envelope (CETPE), a novel on-screen rendering of digital sound

DOI
https://doi.org/10.3280/ria2-2023oa16390
Submitted
agosto 27, 2023
Published
2024-02-14

Abstract

The most widespread forms of digital sound rendering in audio-management software applications include Time/Pressure Envelopes (TPÈs aka “oscillograms”), Frequency/Pressure Analyses (FPA’s), and Time/Frequency Spectrographic Images (TFSI, often referred to as “spectrograms”). Only the latter, thanks to the colour mapping of pressure values, are capable to deliver simultaneously visual information about the three numerical domains (time, horizontal axis; frequency, vertical axis; pressure, colour) digitally defining the acoustic phenomenon.
Here the Colour Enhanced Time/Pressure Envelope (CETPE) is proposed, a 24-bit RGB colour mapped form of the commonplace TPE available on-screen in any digital audio software: this novel Fast Fourier Transform (FFT)-based rendering, controlled by userdefined parameters, is capable to deliver partial but potentially relevant information about the presence and the intensity of interesting frequency bands in an audio file.
A proof-of-concept demonstrator of the 2-color CETPE was developed in Python language, and a sample output screen, consistent with the expected look of the rendering, is included in this paper.

References (including DOI)

  1. H. Nyquist, Certain topics in telegraph transmission theory, Trans. AIEE. 47 (2) (1928) 617-644.
  2. C.E. Shannon, Communication in the presence of noise, P. IRE 37 (1) (1949) 10-21. https://doi.org/10.1109/jrproc.1949.232969
  3. R. Boulanger, V. Lazzarini (Eds.), The Audio Programming Book, The MIT Press, Cambridge, Massachusetts (2011) 209-212.
  4. M.T. Heideman, D.H. Johnson, C.S. Burrus, Gauss and the history of the fast Fourier transform, IEEE ASSP Magazine 1 (4) (1984) 14-21.
  5. J. Smith, Pulse Code Modulation (PCM) in Mathematics of the Discrete Fourier Transform (DFT) with Audio Applications, 2nd
  6. ed., online book (2007). https://ccrma.stanford.edu/~jos/mdft/mdft.html (accessed December 29, 2022).
  7. T.B. Welch, H.G. Wright Cameron, M.G. Morrow, Real-Time Digital Signal Processing from MATLAB to C with the TMS320C6x DSPs, 2nd ed., CRC Press, Boca Raton, USA, 2012.
  8. National Instruments Corporation, White Paper 4278–The Fundamentals of FFT-Based Signal Analysis and Measurement in LabVIEW and LabWindows/CVI, 2018. www.ni.com/whitepaper/4278/en/ (accessed June 10, 2022).
  9. R.B. Blackman, J.W. Tukey, The measurement of power spectra from the point of view of communications engineering, Bell Syst. Tech. J. 37 (1958) 185-282.
  10. F.J. Harris, On the use of windows for harmonic analysis with the discrete Fourier transform, Proc. IEEE 66 (1978) 51-83.
  11. A.H. Nuttall, Some windows with very good sidelobe behavior, IEEE Trans. Acoust. Speech Signal Process 29 (1981) 84-91.
  12. C. Brizio, F.M. Buzzetti, G. Pavan, Beyond the audible: wide band (0-125 kHz) fi eld investigation on Italian Orthoptera (Insecta) songs, Biodiversity Journal, 11 (2) (2020) 443-496. https://doi.org/10.31396/Biodiv.Jour.2020.11.2.443.496
  13. Proof-of-concept, Python source code. www.cesarebrizio.it/CETPE_Python_V4.0.py (accessed November 15, 2023).
  14. Proof-of-concept, Python source code, HTML color-highlighted version. www.cesarebrizio.it/CE-TPE%20HTML%20source.html (accessed November 15, 2023).
  15. Copyright Commons – CC BY-SA 4.0 License deeds https://creativecommons.org/licenses/by-sa/4.0/deed.en (accessed November 15, 2023).
  16. Proof-of-concept, example WAV file. www.cesarebrizio.it/CETPE_Audio_Sample.wav (accessed November 15, 2023).

Metrics

Metrics Loading ...