音频工作站MPEG-I Layer-II码流快速解码混音

Fast decoding and mixing of MPEG-I Layer-II bit streams in Audio workstation

为了能实时完成数字音频工作站中多路MPEG-ILayer-II音频压缩码流的快速解码混音,在分析MPEG-I解码器中的多相滤波器组这个核心算法的基础上,提出了多路MPEG-ILayer-II码流的快速解码混音算法。此算法在进行混音计算时,只需做一次在解码中较为费时的子带综合滤波计算,大大提高了多路混音的速度。实验表明,用该算法进行8路MPEG-ILayer-II解码混音时,在PI-II600MHz的PC机达到了0.25倍实时的解码速度,完全满足了专业数字音频工作站的要求。

In order to fulfil the audio mixing of the decoded MPEG-I Layer-II bitstreamsin real time in the digital audio workstation, an algorithm is proposed for fast real time mixing of MPEG-I Layer-II audio bitstreams after analyzing the kernel algorithm of the polyphase filters in MPEG I decoder. In this algorithm the comparably time-consuming calculation of sub-band signal synthesizing in decoding is done only once for multiple mixing and the speed of mixing is greatly accelerated. By experiments, the algorithm uses only a quarter of the real time when mixing 8 MPEG-I layer-II bitstreams by PIII 600 MHz PC and this completely satisfies the requirement of professional digital audio station.