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参数音频编码是一种基于产生音频信号的参数模型的有效编码方法。最近已用于很低码率的音频编码中,如MPEG-4Version2音频标准HILN。这里提出HILN参数音频编码的改进算法。改进算法采用了自适应的基于倒谱的基频检测算法,利用倒谱和频谱特性,保证了大范围内基频提取的效率和准确性。在正弦波合成中采用相位匹配合成算法,保证了帧间参数的连续性。改进算法还对残差信号进行预处理,去除不必要的干扰分量,最大限度重建原音频信号,提高了合成音频信号的质量。
Parametric audio coding is an efficient coding method based on parametric models that produce audio signals. Recently used for very low bit rate audio coding, such as MPEG-4Version2 audio standard HILN. Here we propose an improved algorithm of audio coding of HILN parameters. The improved algorithm uses an adaptive cepstral-based detection algorithm, which uses cepstrum and spectral features to ensure the efficiency and accuracy of the fundamental frequency extraction in a wide range. In the sine wave synthesis using phase matching synthesis algorithm to ensure the continuity of the parameters between the frames. The improved algorithm also preprocesses the residual signal, removes unnecessary interference components, reconstructs the original audio signal to the maximum, and improves the quality of the synthesized audio signal.