RTCOutboundRtpStreamStats: qualityLimitationDurations property

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

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.

Note: This property only exists for video media.

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.

js
// 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

Specification
Identifiers for WebRTC's Statistics API
# dom-rtcoutboundrtpstreamstats-qualitylimitationdurations

Browser compatibility

desktop mobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
qualityLimitationDurations in 'outbound-rtp' stats
Experimental
Chrome – Full support
Chrome 93 (Release date: 2021-08-31)
footnote Full support
Edge – Full support
Edge 93 (Release date: 2021-09-02)
footnote Full support
Firefox – No support
Firefox
footnote No support
Opera – Full support
Opera 79 (Release date: 2021-09-14)
footnote Full support
Safari – No support
Safari
footnote No support
Chrome Android – Full support
Chrome Android 93 (Release date: 2021-08-31)
footnote Full support
Firefox for Android – No support
Firefox for Android
footnote No support
Opera Android – Full support
Opera Android 66 (Release date: 2021-12-15)
footnote Full support
Safari on iOS – No support
Safari on iOS
footnote No support
Samsung Internet – Full support
Samsung Internet 17 (Release date: 2022-05-04)
footnote Full support
WebView Android – Full support
WebView Android 93 (Release date: 2021-08-31)
footnote Full support
WebView on iOS – No support
WebView on iOS
footnote No support

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support
No support
No support
Experimental. Expect behavior to change in the future.