WebRTC Metrics
A comprehensive overview of WebRTC statistics, derived indicators, and observable signals, to better understand call quality, connectivity, and user experience in rtcStats
SDP content reordered
At least one line in the local SDP was moved to a different position compared to the offer generated by the navigator. This may cause interoperability issues.
Description
Although modern WebRTC APIs provide higher-level controls, SDP sometimes still needs to be modified manually (SDP munging) to force specific behaviors, such as enabling Opus DTX. However, this practice, while still tolerated by browsers, is fragile and error-prone.
What do we do here?
We compare the SDP passed to setLocalDescription against the SDP produced by the preceding createOffer or createAnswer call. When a line is present in both SDPs but appears at a different position, we flag the reordering.
Line reordering is usually benign - most SDP parsers are order-independent within a media section - but it is a reliable signal that manual SDP manipulation is taking place and in some circumstances may cause interoperability issues with the WebRTC stat. Combined with a line modification observation, it helps identify which specific aspect of the SDP is being changed.
