RTCInboundRtpStreamStats.fecPacketsDiscarded - Web APIs
the fecpacketsdiscarded property of the rtcinboundrtpstreamstats dictionary is a numeric value indicating the number of rtp forward error correction (fec) packets that have been discarded.
... syntax var fecpacketsdiscarded = rtcinboundrtpstreamstats.fecpacketsdiscarded; value an unsigned integer value indicating how many fec packets have been received whose error correction payload has been discarded.
... specifications specification status comment identifiers for webrtc's statistics apithe definition of 'rtcinboundrtpstreamstats.fecpacketsdiscarded' in that specification.

RTCInboundRtpStreamStats - Web APIs
fecpacketsdiscarded an integer value indicating the number of rtp forward error correction (fec) packets which have been received for this source, for which the error correction payload was discarded.
...these packets are not counted by packetsdiscarded.
...these packets are not counted by packetsdiscarded.

RTCInboundRtpStreamStats.packetsDuplicated - Web APIs
these packets are not counted by the packetsdiscarded property.
...these duplicate packets are not included in the packetsdiscarded property.

Index - Web APIs
3372 rtcinboundrtpstreamstats.fecpacketsdiscarded api, errors, fec, packets, property, rtcinboundrtpstreamstats, rtp, reference, statistics, stats, webrtc, webrtc api, fecpacketsdiscarded the fecpacketsdiscarded property of the rtcinboundrtpstreamstats dictionary is a numeric value indicating the number of rtp forward error correction (fec) packets that have been discarded.

RTCInboundRtpStreamStats.fecPacketsReceived - Web APIs
if you wish to know how many of the received packets were discarded, you can examine the value of fecpacketsdiscarded.