CAJ | 학술논문

构造了一个音频编码系统,用FV-MLT(Frequency Varying Modulated Lapped Transforms)1实现小波包的变换,进行对输入信号的时频变换。并利用时频变换输出的FV-MLT系数计算遮蔽门限,提出了基于小波包变换的心理声学模型算法。对整个编解码器进行了软件仿真,并与MPEG的标准编解码器进行了音质与压缩率方面的比较。在音质接近的情况下,该编码器的平均码率比Xing AudioCatalyst 2.1标准编码器低10%～20%。
구조료일개음빈편마계통,용FV-MLT(Frequency Varying Modulated Lapped Transforms)1실현소파포적변환,진행대수입신호적시빈변환。병이용시빈변환수출적FV-MLT계수계산차폐문한,제출료기우소파포변환적심리성학모형산법。대정개편해마기진행료연건방진,병여MPEG적표준편해마기진행료음질여압축솔방면적비교。재음질접근적정황하,해편마기적평균마솔비Xing AudioCatalyst 2.1표준편마기저10%～20%。
In this paper an audio coding system is implemented. FV-MLTFrequency Varying Modulated Lapped Transforms1,a kind of wavelet packet transforms is used to realize the time-frequency transform of the input PCM signal. Meanwhile the coefficients of the FV-MLT are also used to calculate the masking threshold and a new computing algorithm of the psychoacoustic model based on the wavelet packet transform is developed. The whole audio coding system is compared with the standard encoder of MPEG on audio quality and compression ratio through software simulation. Given equivalent quality,the average bit rate of the new system is about 10% to 20% lower than that of Xing AudioCatalyst 2.1 encoder which is based on the MPEG standard.