A律pcm编译码,编译码直接放到文件中，pcm编码的过程包括抽样，程序采用30个采样值；量化，量化台阶的变化要考虑四连的情况-Pcm A-law codec, codec file directly into, pcm encoding process including sampling, 30 samples using the program quantify, quantify the level of change to consider the case of four with