Web/API/RTCRtpStreamStats

The RTCRtpStreamStats dictionary is returned by the RTCPeerConnection.getStats(), RTCRtpSender.getStats(), and RTCRtpReceiver.getStats() methods to provide detailed statistics about WebRTC connectivity. While the dictionary has a base set of properties that are present in each of these cases, there are also additional properties added depending on which interface the method is called on.

RTCRtpStreamStats is the base class for all RTP-related statistics reports. It's based on RTCStats and adds the following additional fields.

Note: This interface was called RTCRTPStreamStats until a specification update in the spring of 2017. Check the Browser compatibility table to know if and when the name change was implemented in specific browsers.

Properties

The RTCRtpStreamStats dictionary is based on RTCStats, and inherits its properties. In addition, some or all of the following properties are available.

Standard fields included for all media types

codecId

A DOMString which uniquely identifies the object which was inspected to produce the RTCCodecStats object associated with this RTP stream.

kind

A DOMString whose value is "audio" if the associated MediaStreamTrack is audio-only or "video" if the track contains video. This value will match that of the media type indicated by RTCCodecStats.codec, as well as the track's kind property. Previously called mediaType.

ssrc

The 32-bit integer which identifies the source of the RTP packets this RTCRtpStreamStats object covers. This value is generated per the RFC 3550 specification.

trackId

A DOMString which uniquely identifies the RTCMediaStreamTrackStats object representing the associated MediaStreamTrack. This is not the same as the value of MediaStreamTrack.id.

transportId

A DOMString uniquely identifying the object which was inspected to produce the RTCTransportStats object associated with this RTP stream.

Obsolete fields

mediaType

Renamed to kind in the specification in February 2018. See Browser compatibility in RTCRtpStreamStats.kind to determine when browsers made the transition.

Local-only measurements

These properties are computed locally, and are only available to the device receiving the media stream. Their primary purpose is to examine the error resiliency of the connection, as they provide information about lost packets, lost frames, and how heavily compressed the data is.

firCount

A count of the total number of Full Intra Request (FIR) packets received by the sender. This statistic is only available to the device which is receiving the stream and is only available for video tracks. A FIR packet is sent by the receiving end of the stream when it falls behind or has lost packets and is unable to continue decoding the stream; the sending end of the stream receives the FIR packet and responds by sending a full frame instead of a delta frame, thereby letting the receiver "catch up." The higher this number is, the more often a problem of this nature arose, which can be a sign of network congestion or an overburdened receiving device.

nackCount

The number of times the receiver notified the sender that one or more RTP packets has been lost by sending a Negative ACKnowledgement (NACK, also called "Generic NACK") packet to the sender. This value is only available to the receiver.

pliCount

The number of times the receiving end of the stream sent a Picture Loss Indiciation (PLI) packet to the sender, indicating that it has lost some amount of encoded video data for one or more frames. Only the receiver has this value, and it's only valid for video tracks.

qpSum

The sum of the Quantization Parameter (QP) values associated with every frame received to date on the video track described by this RTCRtpStreamStats object. In general, the higher this number is, the more heavily compressed the video track was. Combined with RTCReceivedRtpStreamStats.framesDecoded or RTCSentRtpStreamStats.framesEncoded, you can approximate the average QP over those frames, keeping in mind that codecs often vary the quantizer values even within frames. Also keep in mind that the values of QP can vary from codec to codec, so this value is only potentially useful when compared against the same codec.

sliCount

The number of times the receiver notified the sender that one or more consecutive (in scan order) encoded video macroblocks have been lost or corrupted; this notification is sent by the receiver to the sender using a Slice Loss Indication (SLI) packet. This is a fairly technical part of how codecs work and while the higher this value is, the more errors occurred in the stream, generally most of the time this value is only interesting to very intensively hardcore media developers.

Specifications

Specification	Status	Comment
Identifiers for WebRTC's Statistics APIThe definition of 'RTCRtpStreamStats' in that specification.	Candidate Recommendation	Initial definition.

Browser compatibility

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
RTCRtpStreamStats	Chrome No support No	Edge No support No	Firefox Full support 63 Full support 63 Full support 27 Alternate Name' Alternate Name' Uses the non-standard name: RTCRTPStreamStats	IE No support No	Opera No support No	Safari ?	WebView Android No support No	Chrome Android No support No	Firefox Android Full support 63 Full support 63 Full support 27 Alternate Name' Alternate Name' Uses the non-standard name: RTCRTPStreamStats	Opera Android No support No	Safari iOS ?	Samsung Internet Android No support No
codecId	Chrome No support No	Edge No support No	Firefox Full support 27	IE No support No	Opera No support No	Safari ?	WebView Android No support No	Chrome Android No support No	Firefox Android Full support 27	Opera Android No support No	Safari iOS ?	Samsung Internet Android No support No
firCount	Chrome No support No	Edge No support No	Firefox Full support 55	IE No support No	Opera No support No	Safari ?	WebView Android No support No	Chrome Android No support No	Firefox Android Full support 55	Opera Android No support No	Safari iOS ?	Samsung Internet Android No support No
isRemote Deprecated'	Chrome No support No	Edge No support No	Firefox Full support 27 Notes' Full support 27 Notes' Notes' In Firefox 28, a default value of false was added for isRemote, to match a specification update.	IE No support No	Opera No support No	Safari ?	WebView Android No support No	Chrome Android No support No	Firefox Android Full support 27 Notes' Full support 27 Notes' Notes' In Firefox 28, a default value of false was added for isRemote, to match a specification update.	Opera Android No support No	Safari iOS ?	Samsung Internet Android No support No
kind	Chrome No support No	Edge No support No	Firefox Full support 63	IE No support No	Opera No support No	Safari ?	WebView Android No support No	Chrome Android No support No	Firefox Android Full support 63	Opera Android No support No	Safari iOS ?	Samsung Internet Android No support No
mediaTrackId Deprecated'	Chrome No support No	Edge No support No	Firefox Full support 27	IE No support No	Opera No support No	Safari ?	WebView Android No support No	Chrome Android No support No	Firefox Android Full support 27	Opera Android No support No	Safari iOS ?	Samsung Internet Android No support No
mediaType Deprecated'	Chrome No support No	Edge No support No	Firefox Full support 34	IE No support No	Opera No support No	Safari ?	WebView Android No support No	Chrome Android No support No	Firefox Android Full support 34	Opera Android No support No	Safari iOS ?	Samsung Internet Android No support No
nackCount	Chrome No support No	Edge No support No	Firefox Full support 55	IE No support No	Opera No support No	Safari ?	WebView Android No support No	Chrome Android No support No	Firefox Android Full support 55	Opera Android No support No	Safari iOS ?	Samsung Internet Android No support No
pliCount	Chrome No support No	Edge No support No	Firefox Full support 55	IE No support No	Opera No support No	Safari ?	WebView Android No support No	Chrome Android No support No	Firefox Android Full support 55	Opera Android No support No	Safari iOS ?	Samsung Internet Android No support No
qpSum	Chrome No support No	Edge No support No	Firefox Full support 66	IE No support No	Opera No support No	Safari ?	WebView Android No support No	Chrome Android No support No	Firefox Android Full support 66	Opera Android No support No	Safari iOS ?	Samsung Internet Android No support No
remoteId Deprecated'	Chrome No support No	Edge No support No	Firefox Full support 27	IE No support No	Opera No support No	Safari ?	WebView Android No support No	Chrome Android No support No	Firefox Android Full support 27	Opera Android No support No	Safari iOS ?	Samsung Internet Android No support No
sliCount	Chrome No support No	Edge No support No	Firefox No support No	IE No support No	Opera No support No	Safari ?	WebView Android No support No	Chrome Android No support No	Firefox Android No support No	Opera Android No support No	Safari iOS ?	Samsung Internet Android No support No
ssrc	Chrome No support No	Edge No support No	Firefox Full support 27	IE No support No	Opera No support No	Safari ?	WebView Android No support No	Chrome Android No support No	Firefox Android Full support 27	Opera Android No support No	Safari iOS ?	Samsung Internet Android No support No
transportId	Chrome No support No	Edge No support No	Firefox Full support 27	IE No support No	Opera No support No	Safari ?	WebView Android No support No	Chrome Android No support No	Firefox Android Full support 27	Opera Android No support No	Safari iOS ?	Samsung Internet Android No support No

Legend

Full support  

Full support

No support  

No support

Compatibility unknown  

Compatibility unknown

Deprecated. Not for use in new websites.'

Deprecated. Not for use in new websites.

See implementation notes.'

See implementation notes.

Uses a non-standard name.'

Uses a non-standard name.

RTCRtpStreamStats by Mozilla Contributors is licensed under CC-BY-SA 2.5.