RTP解包NAL，H264格式，简单实用，实现了单个NAL单元包和FU_A分片单元包。对于丢包处理，采用简单的策略：丢弃随后的所有数据包，直到收到关键帧。-RTP unpack NAL, H264 format, simple and practical, to achieve a single NAL unit packets and fragmentation units FU_A package. For the packet loss treatment, using a simple tactic: dropping all subsequent packets until it receives the key frame.