Adaptive Error Control for Packet

Anecdotal evidence suggests that the quality of many videoconferences in the Internet is mediocre because of high packet loss rates. This makes it important to dee sign and implement mechanisms that minimize packet loss and its impact in video (and audio) applications. There are two such types of mechanisms. Rate control mechanisms attempt to minimize the amount of packet loss by matching the bandwidth requirements of a video ow to the capacity available in the network. However, they do not prevent packet loss altogether. Error conn trol mechanisms attempt to minimize the visual impact of lost packets at the destinations. In this paper, we provide motivation for using error control mechanisms based on forward error correction (FEC) and packet reconstruction. We examine a speciic mechanism, and evaluate its cost as well as the beneet expected from using it. This mechanism can be augmented to obtain a joint source/channel coding scheme suitable for both the current and the future integrated services Internet.