Packet loss concealment (PLC) is a technique to mask the effects of packet loss in voice over IP (VoIP) communications.
One example case of the last situation could be, when a packet is rejected by a server which has a full buffer and cannot accept any more data.
Other cases include network congestion resulting in significant delay.
In a VoIP connection, error-control techniques such as automatic repeat request (ARQ) are usually not feasible and the receiver should be able to cope with packet loss.
[6] Google Duo uses WaveNetEQ, a generative model based on DeepMind/Google AI’s WaveRNN.