  Robustness to packet loss is one of the main ongoing challenges in real-time
speech communication. Deep packet loss concealment (PLC) techniques have
recently demonstrated improved quality compared to traditional PLC. Despite
that, all PLC techniques hit fundamental limitations when too much acoustic
information is lost. To reduce losses in the first place, data is commonly sent
multiple times using various redundancy mechanisms. We propose a neural speech
coder specifically optimized to transmit a large amount of overlapping
redundancy at a very low bitrate, up to 50x redundancy using less than 32~kb/s.
Results show that the proposed redundancy is more effective than the existing
Opus codec redundancy, and that the two can be combined for even greater
robustness.
