Performance Comparison of Linear Prediction based Vocoders in Linux Platform
|International Journal of Engineering Trends and Technology (IJETT)||
|© 2014 by IJETT Journal|
|Year of Publication : 2014|
|Authors : Lani Rachel Mathew , Ancy S. Anselam , Sakuntala S. Pillai
Lani Rachel Mathew , Ancy S. Anselam , Sakuntala S. Pillai. "Performance Comparison of Linear Prediction based Vocoders in Linux Platform", International Journal of Engineering Trends and Technology (IJETT), V10(11),554-558 April 2014. ISSN:2231-5381. www.ijettjournal.org. published by seventh sense research group
Linear predictive coders form an important class of speech coders. This paper describes the software level implementation of linear prediction based vocoders, viz. Code Excited Linear Prediction (CELP), Low-Delay CELP (LD-CELP) and Mixed Excitation Linear Prediction (MELP) at bit rates of 4.8 kb/s, 16 kb/s and 2.4 kb/s respectively. The C programs of the vocoders have been compiled and executed in Linux platform. Subjective testing with the help of Mean Opinion Score test has been performed. Waveform analysis has been done using Praat and Adobe Audition software. The results show that MELP and CELP produce comparable quality while the quality of LD-CELP coder is much higher, at the expense of higher bit rate.
 J. Makhoul, “Linear prediction: A tutorial review,” Proceedings of the IEEE, vol. 63, pp. 561–580, 1975.
 M. Schroeder and B. S. Atal, “Code-excited linear prediction (CELP): High-quality speech at at very low bit rates,” IEEE International Confer- ence on Acoustics, Speech and Signal Processing, vol. 10, pp. 937–940, 1985.
 Juin-Hwey Chen, R. V. Cox, Y. C. Lin, N. Jayant and M. J. Melchner, “A low-delay CELP coder for the CCITT 16 kb/s speech coding standard,” IEEE Journal on Selected Areas in Communications, vol. 10, issue 5, pp. 830–849, 1992.
 Alan McCree, Kwan Truong, E. B. George, T. P. Barnwell and V. Viswanathan, “A 2.4 kbit/s MELP coder candidate for the new U.S. Federal Standard,” IEEE International Conference on Acoustics, Speech, and Signal Processing, vol. 1, pp. 200–203, 1996.
 Lynn M. Supplee, Ronald P. Cohn, John S. Collura and Alan V. Mc- Cree,“MELP: the new Federal Standard at 2400 bps,” IEEE Interna- tional Conference on Acoustics, Speech, and Signal Processing, vol. 2, pp. 1591–1594, 1997.
 L. Mathew, A. Anselam and S. S. Pillai, “Analysis of LD-CELP coder output with Sound eXchange and Praat software,” unpublished.
 Wai C. Chu, “Speech Coding Algorithms: Foundation and Evolution of Standardized Coders,” Wiley Interscience, 2003.
 Olivier Hersent, Jean-Pierre Petit and David Gurle, “Beyond VoIP Pro- tocols: Understanding Voice Technology and Networking Techniques for IP Telephony,” John Wiley & Sons, 2005.
Vocoder, linear prediction, code excited, low delay, mixed excitation, CELP, LD-CELP, MELP, Praat, Linux