chemes is largely limited by the bursty nature of In real-time communications, losses are a result of not the channel losses. In order to combat burst losses, re- only packets dropping over the network, but also late dundant information has to be added into temporally arrival for packets. We introduce different loss-resilient distant packets, which introduce higher delay. techniques for both audio and video in two categories: Another sender-based loss recovery technique, in- client-side techniques and active techniques, depending terleaving, does not increase the data rate of transmission on whether they require any encoder involvement. but still introduces delay at both encoder and decoder sides. The efficiency of loss recovery depends on over 3.6.3.2.1 Client-side techniques how many packets the source packet is interleaved and One category of loss techniques is passive methods that spread over. Again, the wider the spread, the higher the are implemented at the client side, which do not require introduced delay. For low-latency speech communica- any cooperation of the sender or increase the cost of tion, path diversity techniques, presented in [26], have transmission. Client-side techniques impose low over- been demonstrated to be very powerful in combating head for the communication system but can be highly losses. efficient in enhancing the quality of the rendered media. Video communication typically requires much higher To combat channel losses, the client typically employs data transmission rates than audio. A variety of active error-detection and loss-concealment techniques to schemes has been proposed not only to increase the ro- mitigate the effect of lost data. For speech and audio bustness of communication, but also to take the data rate coded techniques based on waveform, most client-side efficiency into consideration [27-29]. Many of the recent schemes take advantage of the data received adjacent to algorithms use rate-distortion (R-D) optimization the lost packet and interpolate the missing informat