RTCOutboundRtpStreamStats: qualityLimitationDurations property

The qualityLimitationDurations property of the RTCOutboundRtpStreamStats dictionary is a map of the reasons that a media stream's quality has been reduced by a codec during encoding, and the time during which the quality was reduced for each reason.

This quality reduction may include changes such as reduced frame rate or resolution, or an increase in compression factor. The information can be used to diagnose throughput issues and optimize performance.

Value

A Map of quality limitation reasons to a number which represents the time in seconds that the stream has been quality limited for that reason.

The allowed quality limitation reason values are the strings:

none

The quality is not limited.

cpu

The quality is primarily limited due to CPU load.

bandwidth

The quality is primarily limited due to congestion cues during bandwidth estimation, such as inter-arrival time and round-trip time.

other

The quality is primarily limited for a reason other than the above.

Examples

Get total time the stream has been quality limited

The sum of all entries except qualityLimitationDurations["none"] gives the total time that the stream has been limited.

// Get the outbound RTP stream stats
pc.getStats().then((stats) => {
  stats.forEach((report) => {
    if (report.type === "outbound-rtp") {
      const qualityLimitations = report.qualityLimitationDurations;
      if (qualityLimitations) {
        let totalTimeLimited = 0;

        console.log("Quality Limitations:");
        qualityLimitations.forEach((duration, reason) => {
          console.log(`- ${reason}: ${duration} seconds`);
          if (reason !== "none") {
            totalTimeLimited += duration;
          }
        });
        console.log(`Total time limited: ${totalTimeLimited}`);
      }
    }
  });
});

Specifications

Browser compatibility