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WebRTC Metrics

A comprehensive overview of WebRTC statistics, derived calculations, extracted features, and observable signals, to better understand call quality, connectivity, and user experience in rtcStats

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outboundaudiovideonetworkstalledStreamOuttype

Stalled outbound stream

No new packets were sent on this outbound stream for an extended period of time. The sender stopped transmitting.

Description

This observation detects when an outbound media stream (audio or video) shows no packet sending activity for an extended period of time.

When does it trigger?

This happens when no new RTP packets are sent during an extended period of time. It can be caused by several factors:

  • Track ended or replaced: The application stopped the capture track or switched the sender to another track
  • Transport down: The connection carrying this stream went down while the capture kept running
  • Application stopped the sender: The application stopped or removed the sender without closing the connection

Note that a muted microphone or a disabled camera track is not a cause: muted tracks keep sending packets (silence or black frames), so the packet counter keeps moving. A frozen counter means the sender really stopped transmitting.

What do we do here?

We look at the cumulative packetsSent counter of any outbound stream and we mark an Observation when the value is the same for at least the 10 last measures.

If the stream was already stalled when the capture started (no packet sent at any point during the recording), the Stalled outbound before capture observation is reported instead.

See also