http://www.rfc-editor.org/rfc/rfc7509.txt
RFC 7509: RTP Control Protocol (RTCP) Extended Report (XR) for Post-Repair Loss Count Metrics, R. Huang, V. Singh2015-05-01T23:00:00-00:00This document defines an RTP Control Protocol (RTCP) Extended Report (XR) block that allows reporting of a post-repair loss count metric for a range of RTP applications. In addition, another metric, repaired loss count, is also introduced in this report block for calculating the pre-repair loss count when needed, so that the RTP sender or a third-party entity is able to evaluate the effectiveness of the repair methods used by the system.