Title :
High quality coding of wideband audio signals using transform coded excitation (TCX)
Author :
Lefebvre, R. ; Salami, R. ; Laflamme, C. ; Adoul, J.-P.
Author_Institution :
Dept. of Electr. Eng., Sherbrooke Univ., Que., Canada
Abstract :
This paper describes the application of transform coded excitation (TCX) coding to encoding wideband speech and audio signals in the bit rate range of 16 kbits/s to 32 kbits/s. The approach uses a combination of time domain (linear prediction; pitch prediction) and frequency domain (transform coding; dynamic bit allocation) techniques, and utilizes a synthesis model similar to that of linear prediction coders such as CELP. However, at the encoder, the high complexity analysis-by-synthesis technique is bypassed by directly quantizing the so-called target signal in the frequency domain. The innovative excitation is derived at the decoder by inverse filtering the quantized target signal. The algorithm is intended for applications whereby a large number of bits is available for the innovative excitation. The TCX algorithm is utilized to encode wideband speech and audio signals with a 50-7000 Hz bandwidth. Novel quantization procedures including inter-frame prediction in the frequency domain are proposed to encode the target signal. The proposed algorithm achieves very high quality for speech at 16 kbits/s, and for music at 24 kbits/s
Keywords :
audio coding; audio signals; filtering theory; frequency-domain analysis; linear predictive coding; music; quantisation (signal); speech coding; time-domain analysis; transform coding; 16 to 32 kbit/s; 50 to 7000 Hz; TCX algorithm; bandwidth; bit rate; dynamic bit allocation; encoder; frequency domain; innovative excitation; inter-frame prediction; inverse filtering; linear prediction; music; pitch prediction; speech quality; synthesis model; target signal quantization; time domain; transform coded excitation; transform coding; wideband audio signals coding; wideband speech signal coding; Bit rate; Encoding; Frequency domain analysis; Predictive models; Signal analysis; Signal synthesis; Speech coding; Speech synthesis; Transform coding; Wideband;
Conference_Titel :
Acoustics, Speech, and Signal Processing, 1994. ICASSP-94., 1994 IEEE International Conference on
Conference_Location :
Adelaide, SA
Print_ISBN :
0-7803-1775-0
DOI :
10.1109/ICASSP.1994.389322