Referential Loss Recovery for Streaming Audio using Application Level Multicast

The demand for real-time multimedia streaming services using application level multicast (ALM) is expected to grow rapidly in the near future and these multimedia applications consists of many media. Especially, the audio media requires a guaranteed quality of service (QoS). The ALM is expected to provide multicast services in a wide area. However, packet losses during transmission are a serious problem in these services as they result in degradation of the QoS. Forward error correction (FEC) is a promising technique to recover the lost packets and improve the QoS of streaming media. In the conventional audio streaming, pre-buffering of media stream and FEC techniques are required to cope with delay jitter and packet losses. However, FEC may degrade the QoS of all communications due to the increased congestion caused by FEC overhead with the increase of streaming sessions. In this paper, a novel FEC method that improves QoS of audio streaming services is proposed. It avoids the increased congestion caused by FEC overhead during media streaming. It also accommodates the delay jitter even without prebuffering of media stream. Furthermore, it provides the QoS according to requirements and environments of users, and location in the multicast tree by using layered coding of FEC. Thus, packet losses and jitter are recovered at each end host using ALM and do not affect the next-hop streaming. The results of computer simulations show that our proposed method provides better audio quality compared to conventional method