"The algorithm must have some knowledge of what is in block N+1 in order to accurately reproduce sample block N. This look ahead" CISCO (2006). Understanding Delay in Packet Voice Networks. CISCO Technology White Paper.
" Opus Codec Overview ... The Opus codec scales ... with algorithmic delays ranging from 5 ms to 65.2 ms." JM. Valin, et al. (2012). Definition of the Opus Audio Codec. IETF RFC6716.
