Dialogic的vox语音格式实际上是一种ADPCM编码，与ITU的G.726 ADPCM算法非常类似。由于ITU的G.726算法比较复杂，实际应用中，多半采用该算法的变体实现。各种变体的区别主要在于参数不同。Dialogic采用的是OKI的一 种实现，称为OKI ADPCM。Windows的.wav格式也包括OKI的ADPCM。-the vox Dialogic voice format is actually a ADPCM encoding, with the ITU G.726 ADP

一个非常好的开源音频编解码项目，支持多种音频采用频率，支持多码流，支持可变速率 Speex a free codec for free speech Speex is an Open Source/Free Software patent-free audio compression format designed for speech. The Speex Project aims to lower the barrier of entry for voice applications

With the development in the image processing field a wide variety of filters have been developed. The quality of filters mainly depends on to which extent it is able to recover the degraded image so that it is as close as to the original image that i