基本实现H261编解码器功能，虽然结果不是很好，但是已经把框架写好的很好，大家只需修改以下熵编码那头文件就可以实现很好的压缩解码功能-H261 codec is basically functional, although the results are not very good, but has already written a very good fr a mework, we simply modify the following files to the other end entr