This paper introduces the framework of a remote surveillance system and key technologies to implementthe framework. A codec based on MPEG-4 is developed to encode and decode video. Both ratio and speed of compression of the codec are improved through the optimal designs of motion estimation,quatization and rate control. Errorcorrection functions added to entropy coding of the codec minimize the loss of quality of images due to transmission error. With a QoS mechanism of transmission and playback based on a simple RTP protocol,this framework is able to adapt bandwidth and to control congestion.
