Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article A Bit Stream Scalable Speech/Audio Coder Combining Enhanced Regular Pulse Excitation and Parametric Coding | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2007 Article ID 74064 14 pages doi 2007 74064 Research Article A Bit Stream Scalable Speech Audio Coder Combining Enhanced Regular Pulse Excitation and Parametric Coding Felip Riera-Palou1 2 and Albertus C. den Brinker1 1 Philips Research Laboratories Digital Signal Processing Group Prof. Holstlaan 4 5656 AA Eindhoven The Netherlands 2 Department of Mathematics and Informatics University of the Balearic Islands Carretera de Valldemossa km 07122 Palma de Mallorca Spain Received 2 October 2006 Revised 16 March 2007 Accepted 29 June 2007 Recommended by Tan Lee This paper introduces a new audio and speech broadband coding technique based on the combination of a pulse excitation coder and a standardized parametric coder namely MPEG-4 high-quality parametric coder. After presenting a series of enhancements to regular pulse excitation RPE to make it suitable for the modeling of broadband signals it is shown how pulse and parametric codings complement each other and how they can be merged to yield a layered bit stream scalable coder able to operate at different points in the quality bit rate plane. The performance of the proposed coder is evaluated in a listening test. The major result is that the extra functionality of the bit stream scalability does not come at the price of a reduced performance since the coder is competitive with standardized coders MP3 AAC SSC . Copyright 2007 F. Riera-Palou and A. C. den Brinker. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. 1. INTRODUCTION During the late eighties and early nineties and with the explosive growth in the use of Internet the need for efficient audio representations became more evident and numerous compression methods were proposed. Coders developed within .
