How to interpret quality in janus.log for RTCP RR

[VIJAY KUMAR]

[Wed Oct  6 12:18:53 2021] [5971706896919329] Incoming RTCP, bundling: this is audio (local SSRC: video=3894829532, audio=3127427585, got 3127427585)

[Wed Oct  6 12:18:53 2021]    Parsing compound packet (total of 32 bytes)

[Wed Oct  6 12:18:53 2021]      #1 RR (201)

[Wed Oct  6 12:18:53 2021] jitter=612.000000, fraction=0, loss=0

[Wed Oct  6 12:18:53 2021] Out link quality=100, media link quality=100

[Wed Oct  6 12:18:53 2021] rtt=66

1. what is the unit of jitter ?

2. what is the benchmark for good quality  for Media link quality and Out Link Quality?

[Alessandro Toppi]

1. as per RFC 3350
interarrival jitter: 32 bits
An estimate of the statistical variance of the RTP data packet interarrival time, measured in timestamp units and expressed as an unsigned integer

2. according to the source
   link_q = !sent ? 0 : 100.0 - (100.0 * nacks / (double)sent);
   media_link_q = !expect ? 0 : 100.0 - (100.0 * lost / (double)expect);
link quality is a measure of how many of the NACKed packets Janus sent, in a time frame between two RRs
media link quality is a measure of how many of the expected packets Janus sent, , in a time frame between two RRs
There is no absolute benchmark, since a loss % might affect the QoE in different ways, depending on the specific media.

[VIJAY KUMAR]

Thanks