说明：  DPCM是differential pulse code modulation的缩写，也就是差分脉冲编码调制的意思。他的主要思想是通过已知的数据预测下一个数据，然后传递预测值与实际值之间的差值。
(DPCM is a differential pulse code modulation acronym, that is, differential pulse code modulation mean. His main idea is known to the data through a data forecast, and then transfer predictive value and the actual value of the difference between.)