This document defines a set of WebIDL objects that allow access to the statistical information about a {{RTCPeerConnection}}.

These objects are returned from the getStats API that is specified in [[WEBRTC]].

Since the previous publication as a Candidate Recommendation, the stats objects were significantly reorganized to better match the underlying data sources. In addition, the networkType property was deprecated for preserving privacy, and the statsended event was removed as no longer needed.

Introduction

Audio, video, or data packets transmitted over a peer-connection can be lost, and experience varying amounts of network delay. A web application implementing WebRTC expects to monitor the performance of the underlying network and media pipeline.

This document defines the statistic identifiers used by the web application to extract metrics from the user agent.

This specification defines the conformance criteria that applies to a single product: the user agent.

Implementations that use ECMAScript to implement the objects defined in this specification MUST implement them in a manner consistent with the ECMAScript Bindings defined in the Web IDL specification [[WEBIDL]], as this document uses that specification and terminology.

This specification does not define what objects a conforming implementation should generate. Specifications that refer to this specification have the need to specify conformance. They should put in their document text that could like this (EXAMPLE ONLY):

Terminology

The terms MediaStream, MediaStreamTrack, and Consumer are defined in [[!GETUSERMEDIA]].

The terms RTCPeerConnection, {{RTCDataChannel}}, {{RTCDtlsTransport}}, {{RTCDtlsTransportState}}, {{RTCIceTransport}}, {{RTCIceRole}}, {{RTCSctpTransport}}, RTCDataChannelState, {{RTCIceCandidateType}}, {{RTCStats}}, {{RTCCertificate}} are defined in [[!WEBRTC]].

RTCPriorityType is defined in [[WEBRTC-PRIORITY]].

The term RTP stream is defined in [[RFC7656]].

The terms Synchronization Source (SSRC), RTCP Sender Report, RTCP Receiver Report are defined in [[RFC3550]].

The term RTCP Extended Report is defined in [[RFC3611]].

An audio sample refers to having a sample in any channel of an audio track - if multiple audio channels are used, metrics based on samples do not increment at a higher rate, simultaneously having samples in multiple channels counts as a single sample.

Basic concepts

The basic object of the stats model is the [= stats object =]. The following terms are defined to describe it:

Monitored object

An internal object that keeps a set of data values. Most monitored objects are object defined in the WebRTC API; they may be thought of as being internal properties of those objects.

Stats object
This is a set of values, copied out from a monitored object at a specific moment in time. It is returned as a WebIDL dictionary through the getStats API call.
Stats object reference

A monitored object has a stable identifier id, which is reflected in all stats objects produced from the monitored object. Stats objects may contain references to other stats objects using this id value. In a [= stats object =], these references are represented by a {{DOMString}} containing id value of the referenced stats object.

All stats object references have type {{DOMString}} and member names ending in Id, or they have type sequence<{{DOMString}}> and member names ending in Ids.

Stats value
Refers to a single value within a stats object.

A monitored object changes the values it contains continuously over its lifetime, but is never visible through the getStats API call. A stats object, once returned, never changes.

The stats API is defined in [[!WEBRTC]]. It is defined to return a collection of [= stats object =]s, each of which is a dictionary inheriting directly or indirectly from the {{RTCStats}} dictionary. This API is normatively defined in [[!WEBRTC]], but is reproduced here for ease of reference.

dictionary RTCStats {
    required DOMHighResTimeStamp timestamp;
    required RTCStatsType        type;
    required DOMString           id;
};
      

Timestamps are expressed with {{DOMHighResTimeStamp}} [[HIGHRES-TIME]], and are defined as {{Performance.timeOrigin}} + {{Performance.now()}} at the time the information is collected.

Guidelines for design of stats objects

When introducing a new stats object, the following principles should be followed:

The new members of the stats dictionary need to be named according to standard practice (camelCase), as per [[API-DESIGN-PRINCIPLES]].

Names ending in Id (such as {{RTCRtpStreamStats/transportId}}) are always a [= stats object reference =]; names ending in Ids (such as {{RTCMediaStreamStats/trackIds}}) are always of type sequence<DOMString>, where each {{DOMString}} is a [= stats object reference =].

If the natural name for a stats value would end in id (such as when the stats value is an in-protocol identifier for the monitored object), the recommended practice is to let the name end in identifier, such as {{RTCDataChannelStats/dataChannelIdentifier}}.

Stats are sampled by Javascript. In general, an application will not have overall control over how often stats are sampled, and the implementation cannot know what the intended use of the stats is. There is, by design, no control surface for the application to influence how stats are generated.

Therefore, letting the implementation compute "average" rates is not a good idea, since that implies some averaging time interval that can't be set beforehand. Instead, the recommended approach is to count the number of measurements of a value and sum the measurements given even if the sum is meaningless in itself; the JS application can then compute averages over any desired time interval by calling getStats() twice, taking the difference of the two sums and dividing by the difference of the two counts.

For stats that are measured against time, such as byte counts, no separate counter is needed; one can instead divide by the difference in the timestamps.

Guidelines for implementing stats objects

When implementing stats objects, the following guidelines should be adhered to:

Lifetime considerations for monitored objects

The object descriptions will say what the lifetime of a [= monitored object =] from the perspective of stats is. When a monitored object is deleted, it no longer appears in stats; until this happens, it will appear. This may or may not correspond to the actual lifetime of an object in an implementation; what matters for this specification is what appears in stats.

If a monitored object can only exist in a few instances over the lifetime of a {{RTCPeerConnection}}, it may be simplest to consider it "eternal" and never delete it from the set of objects reported on in stats. This type of object will remain visible until the {{RTCPeerConnection}} is no longer available; it is also visible in {{RTCPeerConnection/getStats()}} after pc.close(). This is the default when no lifetime is mentioned in its specification.

Objects that might exist in many instances over time should have a defined time at which they are [= deleted =], at which time they stop appearing in subsequent calls to {{RTCPeerConnection/getStats()}}. When an object is [= deleted =], we can guarantee that no subsequent {{RTCPeerConnection/getStats()}} call will contain a [= stats object reference =] that references the deleted object. We also guarantee that the stats id of the deleted object will never be reused for another object. This ensures that an application that collects [= stats object =]s for deleted [= monitored object =]s will always be able to uniquely identify the object pointed to in the result of any {{RTCPeerConnection/getStats()}} call.

Guidelines for {{RTCPeerConnection/getStats()}} results caching/throttling

A call to {{RTCPeerConnection/getStats()}} touches many components of WebRTC and may take significant time to execute. The implementation may or may not utilize caching or throttling of {{RTCPeerConnection/getStats()}} calls for performance benefits, however any implementation must adhere to the following:

When the state of the {{RTCPeerConnection}} visibly changes as a result of an API call, a promise resolving or an event firing, subsequent new {{RTCPeerConnection/getStats()}} calls must return up-to-date dictionaries for the affected objects. For example, if a track is added with {{RTCPeerConnection/addTrack()}} subsequent {{RTCPeerConnection/getStats()}} calls must resolve with a corresponding {{RTCMediaHandlerStats}} object. If you call {{RTCPeerConnection/setRemoteDescription()}} removing a remote track, upon the promise resolving or an associated event (stream's onremovetrack or track's onmute) firing, calling {{RTCPeerConnection/getStats()}} must resolve with an up-to-date {{RTCMediaHandlerStats}} object.

When a stats object is [= deleted =], subsequent {{RTCPeerConnection/getStats()}} calls MUST NOT return stats for that [= monitored object =].

Maintenance procedures for stats object types

Adding new stats objects

This document, in its editors' draft form, serves as the repository for the currently defined set of stats object types including proposals for new standard types.

This document specifies the interoperable stats object types. Proposals for new object types may be made in the editors draft maintained on GitHub. New standard types may appear in future revisions of the W3C Recommendation.

If a need for a new stats object type or stats value within a stats object is found, an issue should be raised on Github, and a review process will decide on whether the stat should be added to the editors draft or not.

A pull request for a change to the editors draft may serve as guidance for the discussion, but the eventual merge is dependent on the review process.

While the WebRTC WG exists, it will serve as the review body; once it has disbanded, the W3C will have to establish appropriate review.

The level of review sought is that of the IETF process' "expert review", as defined in [[RFC5226]] section 4.1. The documentation needed includes the names of the new stats, their data types, and the definitions they are based on, specified to a level that allows interoperable implementation. The specification may consist of references to other documents.

Another specification that wishes to refer to a specific version (for instance for conformance) should refer to a dated version; these will be produced regularly when updates happen.

Retiring stats objects

At times, it makes sense to retire the definition for a stats object or a stats value. When this happens, it is not advisable to simply delete it from the spec, since there may be implementations out there that use it, and it is important that the name is reserved from re-use for another, incompatible definition.

Therefore, retired stats objects are moved to a separate section in this document. Retired stats objects are moved there in their entirety; retired stats values are moved to a "partial dictionary".

If there is no evidence that the retired object definition has ever been used (such as an object that is added to the spec and renamed, redefined or removed prior to implementation), the editors can decide to just remove the object from the spec.

{{RTCStatsType}}

The {{RTCStats/type}} member, of type {{RTCStatsType}}, indicates the type of the object that the {{RTCStats}} object represents. An object with a given {{RTCStats/type}} can have only one IDL dictionary type, but multiple {{RTCStats/type}} values may indicate the same IDL dictionary type; for example, {{RTCStatsType/"local-candidate"}} and {{RTCStatsType/"remote-candidate"}} both use the IDL dictionary type {{RTCIceCandidateStats}}.

This specification is normative for the allowed values of {{RTCStatsType}}.

RTCStatsType enum

enum RTCStatsType {
"codec",
"inbound-rtp",
"outbound-rtp",
"remote-inbound-rtp",
"remote-outbound-rtp",
"media-source",
"csrc",
"peer-connection",
"data-channel",
"stream",
"track",
"transceiver",
"sender",
"receiver",
"transport",
"sctp-transport",
"candidate-pair",
"local-candidate",
"remote-candidate",
"certificate",
"ice-server"
};
        

The following strings are valid values for {{RTCStatsType}}:

codec

Statistics for a codec that is currently being used by RTP streams being sent or received by this {{RTCPeerConnection}} object. It is accessed by the {{RTCCodecStats}}.

inbound-rtp

Statistics for an inbound RTP stream that is currently received with this {{RTCPeerConnection}} object. It is accessed by the {{RTCInboundRtpStreamStats}}.

outbound-rtp

Statistics for an outbound RTP stream that is currently sent with this {{RTCPeerConnection}} object. It is accessed by the {{RTCOutboundRtpStreamStats}}.

When there are multiple RTP streams connected to the same sender due to using simulcast, there will be one {{RTCOutboundRtpStreamStats}} per RTP stream, with distinct values of the {{RTCRtpStreamStats/ssrc}} member, and all these senders will have a reference to the same {{RTCStatsType/"sender"}} object (of type {{RTCAudioSenderStats}} or {{RTCVideoSenderStats}}) and {{RTCStatsType/"track"}} object (of type {{RTCSenderAudioTrackAttachmentStats}} or {{RTCSenderVideoTrackAttachmentStats}}). RTX streams do not show up as separate {{RTCOutboundRtpStreamStats}} objects but affect the {{RTCSentRtpStreamStats/packetsSent}}, {{RTCSentRtpStreamStats/bytesSent}}, {{RTCOutboundRtpStreamStats/retransmittedPacketsSent}} and {{RTCOutboundRtpStreamStats/retransmittedBytesSent}} counters of the relevant {{RTCOutboundRtpStreamStats}} objects.

remote-inbound-rtp

Statistics for the remote endpoint's inbound RTP stream corresponding to an outbound stream that is currently sent with this {{RTCPeerConnection}} object. It is measured at the remote endpoint and reported in an RTCP Receiver Report (RR) or RTCP Extended Report (XR). It is accessed by the {{RTCRemoteInboundRtpStreamStats}}.

remote-outbound-rtp

Statistics for the remote endpoint's outbound RTP stream corresponding to an inbound stream that is currently received with this {{RTCPeerConnection}} object. It is measured at the remote endpoint and reported in an RTCP Sender Report (SR). It is accessed by the {{RTCRemoteOutboundRtpStreamStats}}.

media-source

Statistics for the media produced by a {{MediaStreamTrack}} that is currently attached to an {{RTCRtpSender}}. This reflects the media that is fed to the encoder; after getUserMedia() constraints have been applied (i.e. not the raw media produced by the camera). It is either an {{RTCAudioSourceStats}} or {{RTCVideoSourceStats}} depending on its kind.

csrc

Statistics for a contributing source (CSRC) that contributed to an inbound RTP stream. It is accessed by the {{RTCRtpContributingSourceStats}}.

peer-connection

Statistics related to the {{RTCPeerConnection}} object. It is accessed by the {{RTCPeerConnectionStats}}.

data-channel

Statistics related to each {{RTCDataChannel}} id. It is accessed by the {{RTCDataChannelStats}}.

stream

This is now obsolete. Contains statistics related to a specific {{MediaStream}}. It is accessed by the obsolete dictionary {{RTCMediaStreamStats}}.

track

Statistics related to a specific {{MediaStreamTrack}}'s attachment to an {{RTCRtpSender}} and the corresponding media-level metrics. It is accessed by {{RTCSenderVideoTrackAttachmentStats}}, {{RTCSenderAudioTrackAttachmentStats}}, {{RTCReceiverVideoTrackAttachmentStats}} or {{RTCReceiverAudioTrackAttachmentStats}}, all inherited from {{RTCMediaHandlerStats}}.

The monitored {{RTCStatsType/"track"}} object is [= deleted =] when the sender it reports on has its {{RTCRtpSender/track}} value changed to no longer refer to the same track.

All "track" stats have been made obsolete. The relevant metrics have been moved to "media-source", "sender", "outbound-rtp", "receiver" and "inbound-rtp" stats.

transceiver

Statistics related to a specific {{RTCRtpTransceiver}}. It is accessed by the {{RTCRtpTransceiverStats}} dictionary.

sender

Statistics related to a specific {{RTCRtpSender}} and the corresponding media-level metrics. It is accessed by the {{RTCAudioSenderStats}} or the {{RTCVideoSenderStats}} depending on kind.

receiver

Statistics related to a specific receiver and the corresponding media-level metrics. It is accessed by the {{RTCAudioReceiverStats}} or the {{RTCVideoReceiverStats}} depending on kind.

transport

Transport statistics related to the {{RTCPeerConnection}} object. It is accessed by the {{RTCTransportStats}}.

sctp-transport

SCTP transport statistics related to an {{RTCSctpTransport}} object. It is accessed by the {{RTCSctpTransportStats}} dictionary.

candidate-pair

ICE candidate pair statistics related to the {{RTCIceTransport}} objects. It is accessed by the {{RTCIceCandidatePairStats}}.

A candidate pair that is not the current pair for a transport is [= deleted =] when the {{RTCIceTransport}} does an ICE restart, at the time the state changes to {{RTCIceTransportState/"new"}}. The candidate pair that is the current pair for a transport is [= deleted =] after an ICE restart when the {{RTCIceTransport}} switches to using a candidate pair generated from the new candidates; this time doesn't correspond to any other externally observable event.

local-candidate

ICE local candidate statistics related to the {{RTCIceTransport}} objects. It is accessed by the {{RTCIceCandidateStats}} for the local candidate.

A local candidate is [= deleted =] when the {{RTCIceTransport}} does an ICE restart, and the candidate is no longer a member of any non-deleted candidate pair.

remote-candidate

ICE remote candidate statistics related to the {{RTCIceTransport}} objects. It is accessed by the {{RTCIceCandidateStats}} for the remote candidate.

A remote candidate is [= deleted =] when the {{RTCIceTransport}} does an ICE restart, and the candidate is no longer a member of any non-deleted candidate pair.

certificate

Information about a certificate used by an {{RTCIceTransport}}. It is accessed by the {{RTCCertificateStats}}.

ice-server

Information about the connection to an ICE server (e.g. STUN or TURN). It is accessed by the {{RTCIceServerStats}}.

Stats dictionaries

The RTP statistics hierarchy

The dictionaries for RTP statistics are structured as a hierarchy, so that those stats that make sense in many different contexts are represented just once in IDL.

The metrics exposed here correspond to local measurements and those reported by RTCP packets. Compound RTCP packets contain multiple RTCP report blocks, such as Sender Report (SR) and Receiver Report (RR) whereas a non-compound RTCP packets may contain just a single RTCP SR or RR block.

The lifetime of all RTP [= monitored object =]s starts when the RTP stream is first used: When the first RTP packet is sent or received on the SSRC it represents, or when the first RTCP packet is sent or received that refers to the SSRC of the RTP stream.

RTP monitored objects are not [= deleted =].

The hierarchy is as follows:

{{RTCRtpStreamStats}}: Stats that apply to any end of any RTP stream

RTCRtpStreamStats dictionary

dictionary RTCRtpStreamStats : RTCStats {
             required unsigned long       ssrc;
             required DOMString           kind;
             DOMString           transportId;
             DOMString           codecId;
};

Dictionary {{RTCRtpStreamStats}} Members

ssrc of type unsigned long

The 32-bit unsigned integer value per [[RFC3550]] used to identify the source of the stream of RTP packets that this stats object concerns.

kind of type DOMString

Either "audio" or "video". This MUST match the media type part of the information in the corresponding {{RTCCodecStats/codecType}} member of {{RTCCodecStats}}, and MUST match the kind attribute of the related {{MediaStreamTrack}}.

transportId of type DOMString

It is a unique identifier that is associated to the object that was inspected to produce the {{RTCTransportStats}} associated with this RTP stream.

codecId of type DOMString

It is a unique identifier that is associated to the object that was inspected to produce the {{RTCCodecStats}} associated with this RTP stream.

RTCCodecStats dictionary

This object is created when a codec type is registered for an RTP transport. It may be referenced by multiple RTP streams in media sections using that transport, but similar codecs in different transports have different RTCCodecStats objects.

dictionary RTCCodecStats : RTCStats {
             required unsigned long payloadType;
             RTCCodecType  codecType;
             required DOMString     transportId;
             required DOMString     mimeType;
             unsigned long clockRate;
             unsigned long channels;
             DOMString     sdpFmtpLine;
};

Dictionary {{RTCCodecStats}} Members

payloadType of type unsigned long

Payload type as used in RTP encoding or decoding.

codecType of type {{RTCCodecType}}

{{RTCCodecType/"encode"}} or {{RTCCodecType/"decode"}}, depending on whether this object represents a media format that the implementation is prepared to encode or decode. If the dictionary member is not present, it means that this media format can be both encoded and decoded.

transportId of type DOMString

The unique identifier of the transport on which this codec is being used, which can be used to look up the corresponding {{RTCTransportStats}} object.

mimeType of type DOMString

The codec MIME media type/subtype. e.g., video/vp8 or equivalent.

clockRate of type unsigned long

Represents the media sampling rate.

channels of type unsigned long

Use 2 for stereo, missing for most other cases.

sdpFmtpLine of type DOMString

The a=fmtp line in the SDP corresponding to the codec, i.e., after the colon following the PT. This defined by [[!JSEP]] in Section 5.7.

RTCCodecType enum

enum RTCCodecType {
    "encode",
    "decode",
};
Enumeration description
encode

The attached {{RTCCodecStats}} represents a media format that is being encoded, or that the implementation is prepared to encode.

decode

The attached {{RTCCodecStats}} represents a media format that the implementation is prepared to decode.

RTCReceivedRtpStreamStats dictionary

dictionary RTCReceivedRtpStreamStats : RTCRtpStreamStats {
             unsigned long long   packetsReceived;
             long long            packetsLost;
             double               jitter;
             unsigned long long   packetsDiscarded;
             unsigned long long   packetsRepaired;
             unsigned long long   burstPacketsLost;
             unsigned long long   burstPacketsDiscarded;
             unsigned long        burstLossCount;
             unsigned long        burstDiscardCount;
             double               burstLossRate;
             double               burstDiscardRate;
             double               gapLossRate;
             double               gapDiscardRate;
             unsigned long        framesDropped;
             unsigned long        partialFramesLost;
             unsigned long        fullFramesLost;

};

Dictionary {{RTCReceivedRtpStreamStats}} Members

packetsReceived of type unsigned long long

Total number of RTP packets received for this SSRC. At the receiving endpoint, this is calculated as defined in [[!RFC3550]] section 6.4.1. At the sending endpoint the {{packetsReceived}} can be calculated by subtracting the packets lost from the expected Highest Sequence Number reported in the RTCP Sender Report as discussed in Appendix A.3. in [[!RFC3550]].

packetsLost of type long long

Total number of RTP packets lost for this SSRC. Calculated as defined in [[!RFC3550]] section 6.4.1. Note that because of how this is estimated, it can be negative if more packets are received than sent.

jitter of type double

Packet Jitter measured in seconds for this SSRC. Calculated as defined in section 6.4.1. of [[!RFC3550]].

packetsDiscarded of type unsigned long long

The cumulative number of RTP packets discarded by the jitter buffer due to late or early-arrival, i.e., these packets are not played out. RTP packets discarded due to packet duplication are not reported in this metric [[XRBLOCK-STATS]]. Calculated as defined in [[!RFC7002]] section 3.2 and Appendix A.a.

packetsRepaired of type unsigned long long

The cumulative number of lost RTP packets repaired after applying an error-resilience mechanism [[XRBLOCK-STATS]]. It is measured for the primary source RTP packets and only counted for RTP packets that have no further chance of repair. To clarify, the value is upper-bound to the cumulative number of lost packets. Calculated as defined in [[!RFC7509]] section 3.1 and Appendix A.b.

burstPacketsLost of type unsigned long long

The cumulative number of RTP packets lost during loss bursts, Appendix A (c) of [[!RFC6958]].

burstPacketsDiscarded of type unsigned long long

The cumulative number of RTP packets discarded during discard bursts, Appendix A (b) of [[!RFC7003]].

burstLossCount of type unsigned long

The cumulative number of bursts of lost RTP packets, Appendix A (e) of [[!RFC6958]].

[[!RFC3611]] recommends a Gmin (threshold) value of 16 for classifying a sequence of packet losses or discards as a burst.

burstDiscardCount of type unsigned long

The cumulative number of bursts of discarded RTP packets, Appendix A (e) of [[!RFC8015]].

burstLossRate of type double

The fraction of RTP packets lost during bursts to the total number of RTP packets expected in the bursts. As defined in Appendix A (a) of [[!RFC7004]], however, the actual value is reported without multiplying by 32768.

burstDiscardRate of type double

The fraction of RTP packets discarded during bursts to the total number of RTP packets expected in bursts. As defined in Appendix A (e) of [[!RFC7004]], however, the actual value is reported without multiplying by 32768.

gapLossRate of type double

The fraction of RTP packets lost during the gap periods. Appendix A (b) of [[!RFC7004]], however, the actual value is reported without multiplying by 32768.

gapDiscardRate of type double

The fraction of RTP packets discarded during the gap periods. Appendix A (f) of [[!RFC7004]], however, the actual value is reported without multiplying by 32768.

framesDropped of type unsigned long

Only [= map/exist =]s for video. The total number of frames dropped prior to decode or dropped because the frame missed its display deadline for this receiver's track. The measurement begins when the receiver is created and is a cumulative metric as defined in Appendix A (g) of [[!RFC7004]].

partialFramesLost of type unsigned long

Only [= map/exist =]s for video. The cumulative number of partial frames lost. The measurement begins when the receiver is created and is a cumulative metric as defined in Appendix A (j) of [[!RFC7004]]. This metric is incremented when the frame is sent to the decoder. If the partial frame is received and recovered via retransmission or FEC before decoding, the {{RTCInboundRtpStreamStats/framesReceived}} counter is incremented.

fullFramesLost of type unsigned long

Only [= map/exist =]s for video. The cumulative number of full frames lost. The measurement begins when the receiver is created and is a cumulative metric as defined in Appendix A (i) of [[!RFC7004]].

{{RTCInboundRtpStreamStats}} dictionary

The RTCInboundRtpStreamStats dictionary represents the measurement metrics for the incoming RTP media stream. The timestamp reported in the statistics object is the time at which the data was sampled.

dictionary RTCInboundRtpStreamStats : RTCReceivedRtpStreamStats {
             required DOMString   receiverId;
             DOMString            remoteId;
             unsigned long        framesDecoded;
             unsigned long        keyFramesDecoded;
             unsigned long        frameWidth;
             unsigned long        frameHeight;
             unsigned long        frameBitDepth;
             double               framesPerSecond;
             unsigned long long   qpSum;
             double               totalDecodeTime;
             double               totalInterFrameDelay;
             double               totalSquaredInterFrameDelay;
             boolean              voiceActivityFlag;
             DOMHighResTimeStamp  lastPacketReceivedTimestamp;
             double               averageRtcpInterval;
             unsigned long long   headerBytesReceived;
             unsigned long long   fecPacketsReceived;
             unsigned long long   fecPacketsDiscarded;
             unsigned long long   bytesReceived;
             unsigned long long   packetsFailedDecryption;
             unsigned long long   packetsDuplicated;
             record<USVString, unsigned long long> perDscpPacketsReceived;
             unsigned long        nackCount;
             unsigned long        firCount;
             unsigned long        pliCount;
             unsigned long        sliCount;
             DOMHighResTimeStamp  estimatedPlayoutTimestamp;
             double               jitterBufferDelay;
             unsigned long long   jitterBufferEmittedCount;
             unsigned long long   totalSamplesReceived;
             unsigned long long   samplesDecodedWithSilk;
             unsigned long long   samplesDecodedWithCelt;
             unsigned long long   concealedSamples;
             unsigned long long   silentConcealedSamples;
             unsigned long long   concealmentEvents;
             unsigned long long   insertedSamplesForDeceleration;
             unsigned long long   removedSamplesForAcceleration;
             double               audioLevel;
             double               totalAudioEnergy;
             double               totalSamplesDuration;
             unsigned long        framesReceived;
             DOMString            decoderImplementation;
            };

Dictionary {{RTCInboundRtpStreamStats}} Members

receiverId of type DOMString

The stats ID used to look up the {{RTCAudioReceiverStats}} or {{RTCVideoReceiverStats}} object receiving this stream.

remoteId of type DOMString

The {{remoteId}} is used for looking up the remote {{RTCRemoteOutboundRtpStreamStats}} object for the same SSRC.

framesDecoded

Only [= map/exist =]s for video. It represents the total number of frames correctly decoded for this RTP stream, i.e., frames that would be displayed if no frames are dropped.

keyFramesDecoded of type unsigned long

Only [= map/exist =]s for video. It represents the total number of key frames, such as key frames in VP8 [[RFC6386]] or IDR-frames in H.264 [[RFC6184]], successfully decoded for this RTP media stream. This is a subset of {{framesDecoded}}. framesDecoded - keyFramesDecoded gives you the number of delta frames decoded.

frameWidth of type unsigned long

Only [= map/exist =]s for video. Represents the width of the last decoded frame. Before the first frame is decoded this member does not [= map/exist =].

frameHeight of type unsigned long

Only [= map/exist =]s for video. Represents the height of the last decoded frame. Before the first frame is decoded this member does not [= map/exist =].

frameBitDepth of type unsigned long

Only [= map/exist =]s for video. Represents the bit depth per pixel of the last decoded frame. Typical values are 24, 30, or 36 bits. Before the first frame is decoded this member does not [= map/exist =].

framesPerSecond of type double

Only [= map/exist =]s for video. The number of decoded frames in the last second.

qpSum of type unsigned long long

Only [= map/exist =]s for video. The sum of the QP values of frames decoded by this receiver. The count of frames is in {{framesDecoded}}.

The definition of QP value depends on the codec; for VP8, the QP value is the value carried in the frame header as the syntax element y_ac_qi, and defined in [[RFC6386]] section 19.2. Its range is 0..127.

Note that the QP value is only an indication of quantizer values used; many formats have ways to vary the quantizer value within the frame.

totalDecodeTime of type double

Total number of seconds that have been spent decoding the {{framesDecoded}} frames of this stream. The average decode time can be calculated by dividing this value with {{framesDecoded}}. The time it takes to decode one frame is the time passed between feeding the decoder a frame and the decoder returning decoded data for that frame.

totalInterFrameDelay of type double

Sum of the interframe delays in seconds between consecutively decoded frames, recorded just after a frame has been decoded. The interframe delay variance be calculated from {{totalInterFrameDelay}}, {{totalSquaredInterFrameDelay}}, and {{framesDecoded}} according to the formula: ({{totalSquaredInterFrameDelay}} - {{totalInterFrameDelay}}^2/ {{framesDecoded}})/{{framesDecoded}}.

totalSquaredInterFrameDelay of type double

Sum of the squared interframe delays in seconds between consecutively decoded frames, recorded just after a frame has been decoded. See {{totalInterFrameDelay}} for details on how to calculate the interframe delay variance.

voiceActivityFlag of type boolean

Only [= map/exist =]s for audio. Whether the last RTP packet whose frame was delivered to the {{RTCRtpReceiver}}'s {{MediaStreamTrack}} for playout contained voice activity or not based on the presence of the V bit in the extension header, as defined in [[RFC6464]]. This is the stats-equivalent of {{RTCRtpSynchronizationSource}}.{{RTCRtpSynchronizationSource/voiceActivityFlag}} in [[WEBRTC].

lastPacketReceivedTimestamp of type DOMHighResTimeStamp

Represents the timestamp at which the last packet was received for this SSRC. This differs from {{RTCStats/timestamp}}, which represents the time at which the statistics were generated by the local endpoint.

averageRtcpInterval of type double

The average RTCP interval between two consecutive compound RTCP packets. This is calculated by the sending endpoint when sending compound RTCP reports. Compound packets must contain at least a RTCP RR or SR block and an SDES packet with the CNAME item.

headerBytesReceived of type unsigned long long

Total number of RTP header and padding bytes received for this SSRC. This does not include the size of transport layer headers such as IP or UDP. headerBytesReceived + bytesReceived equals the number of bytes received as payload over the transport.

fecPacketsReceived of type unsigned long long

Total number of RTP FEC packets received for this SSRC. This counter can also be incremented when receiving FEC packets in-band with media packets (e.g., with Opus).

fecPacketsDiscarded of type unsigned long long

Total number of RTP FEC packets received for this SSRC where the error correction payload was discarded by the application. This may happen 1. if all the source packets protected by the FEC packet were received or already recovered by a separate FEC packet, or 2. if the FEC packet arrived late, i.e., outside the recovery window, and the lost RTP packets have already been skipped during playout. This is a subset of {{fecPacketsReceived}}.

bytesReceived of type unsigned long long

Total number of bytes received for this SSRC. Calculated as defined in [[!RFC3550]] section 6.4.1.

packetsFailedDecryption of type unsigned long long

The cumulative number of RTP packets that failed to be decrypted according to the procedures in [[!RFC3711]]. These packets are not counted by {{RTCReceivedRtpStreamStats/packetsDiscarded}}.

packetsDuplicated of type unsigned long long
The cumulative number of packets discarded because they are duplicated. Duplicate packets are not counted in {{RTCReceivedRtpStreamStats/packetsDiscarded}}.
Duplicated packets have the same RTP sequence number and content as a previously received packet. If multiple duplicates of a packet are received, all of them are counted.
An improved estimate of lost packets can be calculated by adding {{packetsDuplicated}} to {{RTCReceivedRtpStreamStats/packetsLost}}; this will always result in a positive number, but not the same number as RFC 3550 would calculate.
perDscpPacketsReceived of type record<USVString, unsigned long long>

Total number of packets received for this SSRC, per Differentiated Services code point (DSCP) [[RFC2474]]. DSCPs are identified as decimal integers in string form. Note that due to network remapping and bleaching, these numbers are not expected to match the numbers seen on sending. Not all OSes make this information available.

firCount of type unsigned long

Only [= map/exist =]s for video. Count the total number of Full Intra Request (FIR) packets sent by this receiver. Calculated as defined in [[!RFC5104]] section 4.3.1. and does not use the metric indicated in [[RFC2032]], because it was deprecated by [[RFC4587]].

pliCount of type unsigned long

Only [= map/exist =]s for video. Count the total number of Picture Loss Indication (PLI) packets sent by this receiver. Calculated as defined in [[!RFC4585]] section 6.3.1.

nackCount of type unsigned long

Count the total number of Negative ACKnowledgement (NACK) packets sent by this receiver. Calculated as defined in [[!RFC4585]] section 6.2.1.

sliCount of type unsigned long

Only [= map/exist =]s for video. Count the total number of Slice Loss Indication (SLI) packets sent by this receiver. Calculated as defined in [[!RFC4585]] section 6.3.2.

estimatedPlayoutTimestamp of type DOMHighResTimeStamp

This is the estimated playout time of this receiver's track. The playout time is the NTP timestamp of the last playable audio sample or video frame that has a known timestamp (from an RTCP SR packet mapping RTP timestamps to NTP timestamps), extrapolated with the time elapsed since it was ready to be played out. This is the "current time" of the track in NTP clock time of the sender and can be present even if there is no audio currently playing.

This can be useful for estimating how much audio and video is out of sync for two tracks from the same source, audioTrackStats.{{estimatedPlayoutTimestamp}} - videoTrackStats.{{estimatedPlayoutTimestamp}}.

jitterBufferDelay of type double

The purpose of the jitter buffer is to recombine RTP packets into frames (in the case of video) and have smooth playout. The model described here assumes that the samples or frames are still compressed and have not yet been decoded. It is the sum of the time, in seconds, each audio sample or a video frame takes from the time the first packet is received by the jitter buffer (ingest timestamp) to the time it exits the jitter buffer (emit timestamp). In the case of audio, several samples belong to the same RTP packet, hence they will have the same ingest timestamp but different jitter buffer emit timestamps. In the case of video, the frame maybe is received over several RTP packets, hence the ingest timestamp is the earliest packet of the frame that entered the jitter buffer and the emit timestamp is when the whole frame exits the jitter buffer. This metric increases upon samples or frames exiting, having completed their time in the buffer (and incrementing {{jitterBufferEmittedCount}}). The average jitter buffer delay can be calculated by dividing the {{jitterBufferDelay}} with the {{jitterBufferEmittedCount}}.

jitterBufferEmittedCount of type unsigned long long

The total number of audio samples or video frames that have come out of the jitter buffer (increasing {{jitterBufferDelay}}).

totalSamplesReceived of type unsigned long long

Only [= map/exist =]s for audio. The total number of samples that have been received on this RTP stream. This includes {{concealedSamples}}.

samplesDecodedWithSilk of type unsigned long long

Only [= map/exist =]s for audio and when the audio codec is Opus. The total number of samples decoded by the SILK portion of the Opus codec.

samplesDecodedWithCelt of type unsigned long long

Only [= map/exist =]s for audio and when the audio codec is Opus. The total number of samples decoded by the CELT portion of the Opus codec.

concealedSamples of type unsigned long long

Only [= map/exist =]s for audio. The total number of samples that are concealed samples. A concealed sample is a sample that was replaced with synthesized samples generated locally before being played out. Examples of samples that have to be concealed are samples from lost packets (reported in {{RTCReceivedRtpStreamStats/packetsLost}}) or samples from packets that arrive too late to be played out (reported in {{RTCReceivedRtpStreamStats/packetsDiscarded}}).

silentConcealedSamples of type unsigned long long

Only [= map/exist =]s for audio. The total number of concealed samples inserted that are "silent". Playing out silent samples results in silence or comfort noise. This is a subset of {{concealedSamples}}.

concealmentEvents of type unsigned long long

Only [= map/exist =]s for audio. The number of concealment events. This counter increases every time a concealed sample is synthesized after a non-concealed sample. That is, multiple consecutive concealed samples will increase the {{concealedSamples}} count multiple times but is a single concealment event.

insertedSamplesForDeceleration of type unsigned long long

Only [= map/exist =]s for audio. When playout is slowed down, this counter is increased by the difference between the number of samples received and the number of samples played out. If playout is slowed down by inserting samples, this will be the number of inserted samples.

removedSamplesForAcceleration of type unsigned long long

Only [= map/exist =]s for audio. When playout is sped up, this counter is increased by the difference between the number of samples received and the number of samples played out. If speedup is achieved by removing samples, this will be the count of samples removed.

audioLevel of type double

Only [= map/exist =]s for audio. Represents the audio level of the receiving track. For audio levels of tracks attached locally, see {{RTCAudioSourceStats}} instead.

The value is between 0..1 (linear), where 1.0 represents 0 dBov, 0 represents silence, and 0.5 represents approximately 6 dBSPL change in the sound pressure level from 0 dBov.

The {{audioLevel}} is averaged over some small interval, using the algortihm described under {{totalAudioEnergy}}. The interval used is implementation dependent.

totalAudioEnergy of type double

Only [= map/exist =]s for audio. Represents the audio energy of the receiving track. For audio energy of tracks attached locally, see {{RTCAudioSourceStats}} instead.

This value MUST be computed as follows: for each audio sample that is received (and thus counted by {{totalSamplesReceived}}), add the sample's value divided by the highest-intensity encodable value, squared and then multiplied by the duration of the sample in seconds. In other words, duration * Math.pow(energy/maxEnergy, 2).

This can be used to obtain a root mean square (RMS) value that uses the same units as {{audioLevel}}, as defined in [[RFC6464]]. It can be converted to these units using the formula Math.sqrt(totalAudioEnergy/totalSamplesDuration). This calculation can also be performed using the differences between the values of two different {{RTCPeerConnection/getStats()}} calls, in order to compute the average audio level over any desired time interval. In other words, do Math.sqrt((energy2 - energy1)/(duration2 - duration1)).

For example, if a 10ms packet of audio is produced with an RMS of 0.5 (out of 1.0), this should add 0.5 * 0.5 * 0.01 = 0.0025 to {{totalAudioEnergy}}. If another 10ms packet with an RMS of 0.1 is received, this should similarly add 0.0001 to {{totalAudioEnergy}}. Then, Math.sqrt(totalAudioEnergy/totalSamplesDuration) becomes Math.sqrt(0.0026/0.02) = 0.36, which is the same value that would be obtained by doing an RMS calculation over the contiguous 20ms segment of audio.

If multiple audio channels are used, the audio energy of a sample refers to the highest energy of any channel.

totalSamplesDuration of type double

Only [= map/exist =]s for audio. Represents the audio duration of the receiving track. For audio durations of tracks attached locally, see {{RTCAudioSourceStats}} instead.

Represents the total duration in seconds of all samples that have been received (and thus counted by {{totalSamplesReceived}}). Can be used with {{totalAudioEnergy}} to compute an average audio level over different intervals.

framesReceived of type unsigned long

Only [= map/exist =]s for video. Represents the total number of complete frames received on this RTP stream. This metric is incremented when the complete frame is received.

decoderImplementation of type DOMString

Identifies the decoder implementation used. This is useful for diagnosing interoperability issues.

If too much information is given here, it increases the fingerprint surface. Since it is only given for active tracks, the incremental exposure is small.

{{RTCRemoteInboundRtpStreamStats}} dictionary

The RTCRemoteInboundRtpStreamStats dictionary represents the remote endpoint's measurement metrics for a particular incoming RTP stream (corresponding to an outgoing RTP stream at the sending endpoint). The timestamp reported in the statistics object is the time at which the corresponding RTCP RR was received.

dictionary RTCRemoteInboundRtpStreamStats : RTCReceivedRtpStreamStats {
             DOMString            localId;
             double               roundTripTime;
             double               totalRoundTripTime;
             double               fractionLost;
             unsigned long long   reportsReceived;
             unsigned long long   roundTripTimeMeasurements;
};

Dictionary {{RTCRemoteInboundRtpStreamStats}} Members

localId of type DOMString

The {{localId}} is used for looking up the local {{RTCOutboundRtpStreamStats}} object for the same SSRC.

roundTripTime of type double

Estimated round trip time for this SSRC based on the RTCP timestamps in the RTCP Receiver Report (RR) and measured in seconds. Calculated as defined in section 6.4.1. of [[!RFC3550]]. If no RTCP Receiver Report is received with a DLSR value other than 0, the round trip time is left undefined.

totalRoundTripTime of type double

Represents the cumulative sum of all round trip time measurements in seconds since the beginning of the session. The individual round trip time is calculated based on the RTCP timestamps in the RTCP Receiver Report (RR) [[!RFC3550]], hence undefined roundtrip are not added. The average round trip time can be computed from {{totalRoundTripTime}} by dividing it by {{roundTripTimeMeasurements}}.

fractionLost of type double

The fraction packet loss reported for this SSRC. Calculated as defined in [[!RFC3550]] section 6.4.1 and Appendix A.3.

reportsReceived of type unsigned long long

Represents the total number of RTCP RR blocks received for this SSRC.

roundTripTimeMeasurements of type unsigned long long

Represents the total number of RTCP RR blocks received for this SSRC that contain a valid round trip time. This counter will increment if the {{roundTripTime}} is undefined.

RTCSentRtpStreamStats dictionary

dictionary RTCSentRtpStreamStats : RTCRtpStreamStats {
             unsigned long      packetsSent;
             unsigned long long bytesSent;
};

Dictionary {{RTCSentRtpStreamStats}} Members

packetsSent of type unsigned long long

Total number of RTP packets sent for this SSRC. This includes retransmissions. Calculated as defined in [[!RFC3550]] section 6.4.1.

bytesSent of type unsigned long long

Total number of bytes sent for this SSRC. This includes retransmissions. Calculated as defined in [[!RFC3550]] section 6.4.1.

{{RTCOutboundRtpStreamStats}} dictionary

The RTCOutboundRtpStreamStats dictionary represents the measurement metrics for the outgoing RTP stream. The timestamp reported in the statistics object is the time at which the data was sampled.

dictionary RTCOutboundRtpStreamStats : RTCSentRtpStreamStats {
             unsigned long        rtxSsrc;
             DOMString            mediaSourceId;
             DOMString            senderId;
             DOMString            remoteId;
             DOMString            rid;
             DOMHighResTimeStamp  lastPacketSentTimestamp;
             unsigned long long   headerBytesSent;
             unsigned long        packetsDiscardedOnSend;
             unsigned long long   bytesDiscardedOnSend;
             unsigned long        fecPacketsSent;
             unsigned long long   retransmittedPacketsSent;
             unsigned long long   retransmittedBytesSent;
             double               targetBitrate;
             unsigned long long   totalEncodedBytesTarget;
             unsigned long        frameWidth;
             unsigned long        frameHeight;
             unsigned long        frameBitDepth;
             double               framesPerSecond;
             unsigned long        framesSent;
             unsigned long        hugeFramesSent;
             unsigned long        framesEncoded;
             unsigned long        keyFramesEncoded;
             unsigned long        framesDiscardedOnSend;
             unsigned long long   qpSum;
             unsigned long long   totalSamplesSent;
             unsigned long long   samplesEncodedWithSilk;
             unsigned long long   samplesEncodedWithCelt;
             boolean              voiceActivityFlag;
             double               totalEncodeTime;
             double               totalPacketSendDelay;
             double               averageRtcpInterval;
             RTCQualityLimitationReason                 qualityLimitationReason;
             record<DOMString, double> qualityLimitationDurations;
             unsigned long        qualityLimitationResolutionChanges;
             record<USVString, unsigned long long> perDscpPacketsSent;
             unsigned long        nackCount;
             unsigned long        firCount;
             unsigned long        pliCount;
             unsigned long        sliCount;
             DOMString            encoderImplementation;
};

Dictionary {{RTCOutboundRtpStreamStats}} Members

rtxSsrc of type unsigned long

If RTX is negotiated as a separate stream, this is the SSRC of the RTX stream that is associated with this stream's {{RTCRtpStreamStats/ssrc}}. If RTX is not negotiated, this value is not present. Whether or not RTX is negotiated, retransmissions are accounted for in the {{RTCSentRtpStreamStats/bytesSent}} and {{RTCOutboundRtpStreamStats/retransmittedBytesSent}} stats of this object.

mediaSourceId of type DOMString
The identifier of the stats object representing the track currently attached to the sender of this stream, an {{RTCMediaSourceStats}}.
senderId of type DOMString

The stats ID used to look up the {{RTCAudioSenderStats}} or {{RTCVideoSenderStats}} object sending this stream.

remoteId of type DOMString

The {{remoteId}} is used for looking up the remote {{RTCRemoteInboundRtpStreamStats}} object for the same SSRC.

rid of type DOMString

Exposes the {{RTCRtpCodingParameters/rid}} encoding parameter of this RTP stream if it has been set, otherwise it is undefined. If set this value will be present regardless if the RID RTP header extension has been negotiated.

lastPacketSentTimestamp of type DOMHighResTimeStamp

Represents the timestamp at which the last packet was sent for this SSRC. This differs from {{RTCStats/timestamp}}, which represents the time at which the statistics were generated by the local endpoint.

headerBytesSent of type unsigned long long

Total number of RTP header and padding bytes sent for this SSRC. This does not include the size of transport layer headers such as IP or UDP. headerBytesSent + bytesSent equals the number of bytes sent as payload over the transport.

packetsDiscardedOnSend of type unsigned long

Total number of RTP packets for this SSRC that have been discarded due to socket errors, i.e. a socket error occured when handing the packets to the socket. This might happen due to various reasons, including full buffer or no available memory.

bytesDiscardedOnSend of type unsigned long long

Total number of bytes for this SSRC that have been discarded due to socket errors, i.e. a socket error occured when handing the packets containing the bytes to the socket. This might happen due to various reasons, including full buffer or no available memory. Calculated as defined in [[!RFC3550]] section 6.4.1.

fecPacketsSent of type unsigned long

Total number of RTP FEC packets sent for this SSRC. This counter can also be incremented when sending FEC packets in-band with media packets (e.g., with Opus).

retransmittedPacketsSent of type unsigned long long

The total number of packets that were retransmitted for this SSRC. This is a subset of {{RTCSentRtpStreamStats/packetsSent}}. If RTX is not negotiated, retransmitted packets are sent over this {{RTCRtpStreamStats/ssrc}}. If RTX was negotiated, retransmitted packets are sent over a separate {{RTCOutboundRtpStreamStats/rtxSsrc}}.

retransmittedBytesSent of type unsigned long long

The total number of bytes that were retransmitted for this SSRC, only including payload bytes. This is a subset of {{RTCSentRtpStreamStats/bytesSent}}. If RTX is not negotiated, retransmitted bytes are sent over this {{RTCRtpStreamStats/ssrc}}. If RTX was negotiated, retransmitted bytes are sent over a separate {{RTCOutboundRtpStreamStats/rtxSsrc}}.

targetBitrate of type double

Reflects the current encoder target in bits per second. The target is an instantanous value reflecting the encoder's settings, but the resulting payload bytes sent per second, excluding retransmissions, SHOULD closely correlate to the target. See also {{RTCSentRtpStreamStats/bytesSent}} and {{RTCOutboundRtpStreamStats/retransmittedBytesSent}}. The {{targetBitrate}} is defined in the same way as the Transport Independent Application Specific (TIAS) bitrate [[!RFC3890]].

totalEncodedBytesTarget of type unsigned long long

This value is increased by the target frame size in bytes every time a frame has been encoded. The actual frame size may be bigger or smaller than this number. This value goes up every time {{framesEncoded}} goes up.

frameWidth of type unsigned long

Only [= map/exist =]s for video. Represents the width of the last encoded frame. The resolution of the encoded frame may be lower than the media source (see {{RTCVideoSourceStats.width}}). Before the first frame is encoded this member does not [= map/exist =].

frameHeight of type unsigned long

Only [= map/exist =]s for video. Represents the height of the last encoded frame. The resolution of the encoded frame may be lower than the media source (see {{RTCVideoSourceStats.height}}). Before the first frame is encoded this member does not [= map/exist =].

frameBitDepth of type unsigned long

Only [= map/exist =]s for video. Represents the bit depth per pixel of the last encoded frame. Typical values are 24, 30, or 36 bits. Before the first frame is encoded this member does not [= map/exist =].

framesPerSecond of type double

Only [= map/exist =]s for video. The number of encoded frames during the last second. This may be lower than the media source frame rate (see {{RTCVideoSourceStats.framesPerSecond}}).

framesSent of type unsigned long

Only [= map/exist =]s for video. Represents the total number of frames sent on this RTP stream.

hugeFramesSent of type unsigned long

Only [= map/exist =]s for video. Represents the total number of huge frames sent by this RTP stream. Huge frames, by definition, are frames that have an encoded size at least 2.5 times the average size of the frames. The average size of the frames is defined as the target bitrate per second divided by the target FPS at the time the frame was encoded. These are usually complex to encode frames with a lot of changes in the picture. This can be used to estimate, e.g slide changes in the streamed presentation.

The multiplier of 2.5 is choosen from analyzing encoded frame sizes for a sample presentation using WebRTC standalone implementation. 2.5 is a reasonably large multiplier which still caused all slide change events to be identified as a huge frames. It, however, produced 1.4% of false positive slide change detections which is deemed reasonable.

framesEncoded of type unsigned long

Only [= map/exist =]s for video. It represents the total number of frames successfully encoded for this RTP media stream.

keyFramesEncoded of type unsigned long

Only [= map/exist =]s for video. It represents the total number of key frames, such as key frames in VP8 [[RFC6386]] or IDR-frames in H.264 [[RFC6184]], successfully encoded for this RTP media stream. This is a subset of {{framesEncoded}}. framesEncoded - keyFramesEncoded gives you the number of delta frames encoded.

framesDiscardedOnSend of type unsigned long

Total number of video frames that have been discarded for this SSRC due to socket errors, i.e. a socket error occured when handing the packets to the socket. This might happen due to various reasons, including full buffer or no available memory.

qpSum of type unsigned long long

Only [= map/exist =]s for video. The sum of the QP values of frames encoded by this sender. The count of frames is in {{framesEncoded}}.

The definition of QP value depends on the codec; for VP8, the QP value is the value carried in the frame header as the syntax element y_ac_qi, and defined in [[RFC6386]] section 19.2. Its range is 0..127.

Note that the QP value is only an indication of quantizer values used; many formats have ways to vary the quantizer value within the frame.

totalSamplesSent of type unsigned long long

Only [= map/exist =]s for audio. The total number of samples that have been sent over this RTP stream.

samplesEncodedWithSilk of type unsigned long long

Only [= map/exist =]s for audio and when the audio codec is Opus. The total number of samples encoded by the SILK portion of the Opus codec.

samplesEncodedWithCelt of type unsigned long long

Only [= map/exist =]s for audio and when the audio codec is Opus. The total number of samples encoded by the CELT portion of the Opus codec.

voiceActivityFlag of type boolean

Only [= map/exist =]s for audio. Whether the last RTP packet sent contained voice activity or not based on the presence of the V bit in the extension header, as defined in [[RFC6464]].

totalEncodeTime of type double

Total number of seconds that has been spent encoding the {{framesEncoded}} frames of this stream. The average encode time can be calculated by dividing this value with {{framesEncoded}}. The time it takes to encode one frame is the time passed between feeding the encoder a frame and the encoder returning encoded data for that frame. This does not include any additional time it may take to packetize the resulting data.

totalPacketSendDelay of type double

The total number of seconds that packets have spent buffered locally before being transmitted onto the network. The time is measured from when a packet is emitted from the RTP packetizer until it is handed over to the OS network socket. This measurement is added to {{totalPacketSendDelay}} when {{RTCSentRtpStreamStats/packetsSent}} is incremented.

averageRtcpInterval of type double

The average RTCP interval between two consecutive compound RTCP packets. This is calculated by the sending endpoint when sending compound RTCP reports. Compound packets must contain at least a RTCP RR or SR block and an SDES packet with the CNAME item.

qualityLimitationReason of type {{RTCQualityLimitationReason}}

Only [= map/exist =]s for video. The current reason for limiting the resolution and/or framerate, or {{RTCQualityLimitationReason/"none"}} if not limited.

The implementation reports the most limiting factor. If the implementation is not able to determine the most limiting factor because multiple may exist, the reasons MUST be reported in the following order of priority: "bandwidth", "cpu", "other".

The consumption of CPU and bandwidth resources is interdependent and difficult to estimate, making it hard to determine what the "most limiting factor" is. The priority order promoted here is based on the heuristic that "bandwidth" is generally more varying and thus a more likely and more useful signal than "cpu".

qualityLimitationDurations of type record<DOMString, double>

Only [= map/exist =]s for video. A record of the total time, in seconds, that this stream has spent in each quality limitation state. The record includes a mapping for all {{RTCQualityLimitationReason}} types, including {{RTCQualityLimitationReason/"none"}}.

The sum of all entries minus {{qualityLimitationDurations}}[{{RTCQualityLimitationReason/"none"}}] gives the total time that the stream has been limited.

qualityLimitationResolutionChanges of type unsigned long

Only [= map/exist =]s for video. The number of times that the resolution has changed because we are quality limited ({{qualityLimitationReason}} has a value other than {{RTCQualityLimitationReason/"none"}}). The counter is initially zero and increases when the resolution goes up or down. For example, if a 720p track is sent as 480p for some time and then recovers to 720p, {{qualityLimitationResolutionChanges}} will have the value 2.

perDscpPacketsSent of type record<USVString, unsigned long long>

Total number of packets sent for this SSRC, per DSCP. DSCPs are identified as decimal integers in string form.

nackCount of type unsigned long

Count the total number of Negative ACKnowledgement (NACK) packets received by this sender. Calculated as defined in [[!RFC4585]] section 6.2.1.

firCount of type unsigned long

Only [= map/exist =]s for video. Count the total number of Full Intra Request (FIR) packets received by this sender. Calculated as defined in [[!RFC5104]] section 4.3.1. and does not use the metric indicated in [[RFC2032]], because it was deprecated by [[RFC4587]].

pliCount of type unsigned long

Only [= map/exist =]s for video. Count the total number of Picture Loss Indication (PLI) packets received by this sender. Calculated as defined in [[!RFC4585]] section 6.3.1.

sliCount of type unsigned long

Only [= map/exist =]s for video. Count the total number of Slice Loss Indication (SLI) packets received by this sender. Calculated as defined in [[!RFC4585]] section 6.3.2.

encoderImplementation of type DOMString

Identifies the encoder implementation used. This is useful for diagnosing interoperability issues.

If too much information is given here, it increases the fingerprint surface. Since it is only given for active tracks, the incremental exposure is small.

RTCQualityLimitationReason enum

enum RTCQualityLimitationReason {
            "none",
            "cpu",
            "bandwidth",
            "other",
          };
Enumeration description
none

The resolution and/or framerate is not limited.

cpu

The resolution and/or framerate is primarily limited due to CPU load.

bandwidth

The resolution and/or framerate is primarily limited due to congestion cues during bandwidth estimation. Typical, congestion control algorithms use inter-arrival time, round-trip time, packet or other congestion cues to perform bandwidth estimation.

other

The resolution and/or framerate is primarily limited for a reason other than the above.

{{RTCRemoteOutboundRtpStreamStats}} dictionary

The RTCRemoteOutboundRtpStreamStats dictionary represents the remote endpoint's measurement metrics for its outgoing RTP stream (corresponding to an outgoing RTP stream at the sending endpoint). The timestamp reported in the statistics object is the time at which the corresponding RTCP SR was received.

dictionary RTCRemoteOutboundRtpStreamStats : RTCSentRtpStreamStats {
             DOMString           localId;
             DOMHighResTimeStamp remoteTimestamp;
             unsigned long long  reportsSent;
};

Dictionary {{RTCRemoteOutboundRtpStreamStats}} Members

localId of type DOMString

The {{localId}} is used for looking up the local {{RTCInboundRtpStreamStats}} object for the same SSRC.

remoteTimestamp of type DOMHighResTimeStamp

{{remoteTimestamp}}, of type {{DOMHighResTimeStamp}} [[!HIGHRES-TIME]], represents the remote timestamp at which these statistics were sent by the remote endpoint. This differs from {{RTCStats/timestamp}}, which represents the time at which the statistics were generated or received by the local endpoint. The {{remoteTimestamp}}, if present, is derived from the NTP timestamp in an RTCP Sender Report (SR) block, which reflects the remote endpoint's clock. That clock may not be synchronized with the local clock.

reportsSent of type unsigned long long

Represents the total number of RTCP SR blocks sent for this SSRC.

{{RTCMediaSourceStats}} dictionary

The RTCMediaSourceStats dictionary represents a track that is currently attached to one or more senders. It contains information about media sources such as frame rate and resolution prior to encoding. This is the media passed from the {{MediaStreamTrack}} to the {{RTCRtpSender}}s. This is in contrast to {{RTCOutboundRtpStreamStats}} whose members describe metrics as measured after the encoding step. For example, a track may be captured from a high-resolution camera, its frames downscaled due to track constraints and then further downscaled by the encoders due to CPU and network conditions. This dictionary reflects the video frames or audio samples passed out from the track - after track constraints have been applied but before any encoding or further donwsampling occurs.

Media source objects are of either subdictionary {{RTCAudioSourceStats}} or {{RTCVideoSourceStats}}. The {{RTCStats/type}} is the same ({{RTCStatsType/"media-source"}}) but {{RTCMediaSourceStats/kind}} is different ("audio" or "video") depending on the kind of track.

The media source stats objects are created when a track is attached to any {{RTCRtpSender}} and may subsequently be attached to multiple senders during its life. The life of this object ends when the track is no longer attached to any sender of the same {{RTCPeerConnection}}. If a track whose media source object ended is attached again this results in a new media source stats object whose counters (such as number of frames) are reset.

dictionary RTCMediaSourceStats : RTCStats {
             required DOMString       trackIdentifier;
             required DOMString       kind;
             boolean         relayedSource;
};

Dictionary {{RTCMediaSourceStats}} Members

trackIdentifier of type DOMString

The value of the {{MediaStreamTrack}}'s id attribute.

kind of type DOMString

The value of the {{MediaStreamTrack}}'s kind attribute. This is either "audio" or "video". If it is "audio" then this stats object is of type {{RTCAudioSourceStats}}. If it is "video" then this stats object is of type {{RTCVideoSourceStats}}.

relayedSource of type boolean
true if the source is remote, for instance if it is sourced from another host via an {{RTCPeerConnection}}. false otherwise.

{{RTCAudioSourceStats}} dictionary

The RTCAudioSourceStats dictionary represents an audio track that is attached to one or more senders. It is an {{RTCMediaSourceStats}} whose {{RTCMediaSourceStats/kind}} is "audio".

dictionary RTCAudioSourceStats : RTCMediaSourceStats {
              double              audioLevel;
              double              totalAudioEnergy;
              double              totalSamplesDuration;
              double              echoReturnLoss;
              double              echoReturnLossEnhancement;
};

Dictionary {{RTCAudioSourceStats}} Members

audioLevel of type double

Represents the audio level of the media source. For audio levels of remotely sourced tracks, see {{RTCAudioReceiverStats}} instead.

The value is between 0..1 (linear), where 1.0 represents 0 dBov, 0 represents silence, and 0.5 represents approximately 6 dBSPL change in the sound pressure level from 0 dBov.

The {{audioLevel}} is averaged over some small interval, using the algortihm described under {{totalAudioEnergy}}. The interval used is implementation dependent.

totalAudioEnergy of type double

Represents the audio energy of the media source. For audio energy of remotely sourced tracks, see {{RTCAudioReceiverStats}} instead.

This value MUST be computed as follows: for each audio sample produced by the media source during the lifetime of this stats object, add the sample's value divided by the highest-intensity encodable value, squared and then multiplied by the duration of the sample in seconds. In other words, duration * Math.pow(energy/maxEnergy, 2).

This can be used to obtain a root mean square (RMS) value that uses the same units as {{audioLevel}}, as defined in [[RFC6464]]. It can be converted to these units using the formula Math.sqrt(totalAudioEnergy/totalSamplesDuration). This calculation can also be performed using the differences between the values of two different {{RTCPeerConnection/getStats()}} calls, in order to compute the average audio level over any desired time interval. In other words, do Math.sqrt((energy2 - energy1)/(duration2 - duration1)).

For example, if a 10ms packet of audio is produced with an RMS of 0.5 (out of 1.0), this should add 0.5 * 0.5 * 0.01 = 0.0025 to {{totalAudioEnergy}}. If another 10ms packet with an RMS of 0.1 is received, this should similarly add 0.0001 to {{totalAudioEnergy}}. Then, Math.sqrt(totalAudioEnergy/totalSamplesDuration) becomes Math.sqrt(0.0026/0.02) = 0.36, which is the same value that would be obtained by doing an RMS calculation over the contiguous 20ms segment of audio.

If multiple audio channels are used, the audio energy of a sample refers to the highest energy of any channel.

totalSamplesDuration of type double

Represents the audio duration of the media source. For audio durations of remotely sourced tracks, see {{RTCAudioReceiverStats}} instead.

Represents the total duration in seconds of all samples that have been produced by this source for the lifetime of this stats object. Can be used with {{totalAudioEnergy}} to compute an average audio level over different intervals.

echoReturnLoss of type double

Only [= map/exist =]s when the {{MediaStreamTrack}} is sourced from a microphone where echo cancellation is applied. Calculated in decibels, as defined in [[!ECHO]] (2012) section 3.14.

If multiple audio channels are used, the channel of the least audio energy is considered for any sample.

echoReturnLossEnhancement of type double

Only [= map/exist =]s when the {{MediaStreamTrack}} is sourced from a microphone where echo cancellation is applied. Calculated in decibels, as defined in [[!ECHO]] (2012) section 3.15.

If multiple audio channels are used, the channel of the least audio energy is considered for any sample.

{{RTCVideoSourceStats}} dictionary

The RTCVideoSourceStats dictionary represents a video track that is attached to one or more senders. It is an {{RTCMediaSourceStats}} whose {{RTCMediaSourceStats/kind}} is "video".

dictionary RTCVideoSourceStats : RTCMediaSourceStats {
             unsigned long   width;
             unsigned long   height;
             unsigned long   bitDepth;
             unsigned long   frames;
             double          framesPerSecond;
};

Dictionary {{RTCVideoSourceStats}} Members

width of type unsigned long

The width, in pixels, of the last frame originating from this source. Before a frame has been produced this member does not [= map/exist =].

height of type unsigned long

The height, in pixels, of the last frame originating from this source. Before a frame has been produced this member does not [= map/exist =].

bitDepth of type unsigned long

The bit depth per pixel of the last frame originating from this source. Before a frame has been produced this member does not [= map/exist =].

frames of type frames

The total number of frames originating from this source.

framesPerSecond of type double

The number of frames originating from this source, measured during the last second. For the first second of this object's lifetime this member does not [= map/exist =].

RTCRtpContributingSourceStats dictionary

The {{RTCRtpContributingSourceStats}} dictionary represents the measurement metrics for a contributing source (CSRC) that is contributing to an incoming RTP stream. Each contributing source produces a stream of RTP packets, which are combined by a mixer into a single stream of RTP packets that is ultimately received by the WebRTC endpoint. Information about the sources that contributed to this combined stream may be provided in the CSRC list or [[RFC6465]] header extension of received RTP packets. The {{RTCStats/timestamp}} of this stats object is the most recent time an RTP packet the source contributed to was received and counted by {{RTCRtpContributingSourceStats/packetsContributedTo}}.

dictionary RTCRtpContributingSourceStats : RTCStats {
             required unsigned long contributorSsrc;
             required DOMString     inboundRtpStreamId;
             unsigned long packetsContributedTo;
             double        audioLevel;
};

Dictionary {{RTCRtpContributingSourceStats}} Members

contributorSsrc of type unsigned long

The SSRC identifier of the contributing source represented by this stats object, as defined by [[!RFC3550]]. It is a 32-bit unsigned integer that appears in the CSRC list of any packets the relevant source contributed to.

inboundRtpStreamId of type DOMString

The ID of the {{RTCInboundRtpStreamStats}} object representing the inbound RTP stream that this contributing source is contributing to.

packetsContributedTo of type unsigned long

The total number of RTP packets that this contributing source contributed to. This value is incremented each time a packet is counted by {{RTCInboundRtpStreamStats}}.{{RTCReceivedRtpStreamStats/packetsReceived}}, and the packet's CSRC list (as defined by [[!RFC3550]] section 5.1) contains the SSRC identifier of this contributing source, {{contributorSsrc}}.

audioLevel of type double

Present if the last received RTP packet that this source contributed to contained an [[!RFC6465]] mixer-to-client audio level header extension. The value of {{audioLevel}} is between 0..1 (linear), where 1.0 represents 0 dBov, 0 represents silence, and 0.5 represents approximately 6 dBSPL change in the sound pressure level from 0 dBov.

The [[!RFC6465]] header extension contains values in the range 0..127, in units of -dBov, where 127 represents silence. To convert these values to the linear 0..1 range of {{audioLevel}}, a value of 127 is converted to 0, and all other values are converted using the equation: f(rfc6465_level) = 10^(-rfc6465_level/20).

RTCPeerConnectionStats dictionary

dictionary RTCPeerConnectionStats : RTCStats {
            unsigned long dataChannelsOpened;
            unsigned long dataChannelsClosed;
            unsigned long dataChannelsRequested;
            unsigned long dataChannelsAccepted;
};

Dictionary {{RTCPeerConnectionStats}} Members

dataChannelsOpened of type unsigned long

Represents the number of unique {{RTCDataChannel}}s that have entered the {{RTCDataChannelState/"open"}} state during their lifetime.

dataChannelsClosed of type unsigned long

Represents the number of unique {{RTCDataChannel}}s that have left the {{RTCDataChannelState/"open"}} state during their lifetime (due to being closed by either end or the underlying transport being closed). {{RTCDataChannel}}s that transition from {{RTCDataChannelState/"connecting"}} to {{RTCDataChannelState/"closing"}} or {{RTCDataChannelState/"closed"}} without ever being {{RTCDataChannelState/"open"}} are not counted in this number.

dataChannelsRequested of type unsigned long

Represents the number of unique {{RTCDataChannel}}s returned from a successful {{RTCPeerConnection/createDataChannel()}} call on the {{RTCPeerConnection}}. If the underlying data transport is not established, these may be in the {{RTCDataChannelState/"connecting"}} state.

dataChannelsAccepted of type unsigned long

Represents the number of unique {{RTCDataChannel}}s signaled in a {{RTCPeerConnection/ondatachannel}} event on the {{RTCPeerConnection}}.

The total number of open data channels at any time can be calculated as {{RTCPeerConnectionStats/dataChannelsOpened}} - {{RTCPeerConnectionStats/dataChannelsClosed}}. This number is always positive.

The sum of {{RTCPeerConnectionStats/dataChannelsRequested}} and {{RTCPeerConnectionStats/dataChannelsAccepted}} is always greater than or equal to {{RTCPeerConnectionStats/dataChannelsOpened}} - the difference is equal to the number of channels that have been requested, but have not reached the {{RTCDataChannelState/"open"}} state.

RTCRtpTransceiverStats dictionary

An {{RTCRtpTransceiverStats}} stats object represents an {{RTCRtpTransceiver}} of an {{RTCPeerConnection}}.

It appears as soon as the monitored {{RTCRtpTransceiver}} object is created, such as by invoking {{RTCPeerConnection/addTransceiver()}}, {{RTCPeerConnection/addTrack()}} or {{RTCPeerConnection/setRemoteDescription()}}. {{RTCRtpTransceiverStats}} objects can only be deleted if the corresponding {{RTCRtpTransceiver}} is removed - this can only happen if a remote description is rolled back.

dictionary RTCRtpTransceiverStats : RTCStats {
    required DOMString senderId;
    required DOMString receiverId;
    DOMString mid;
};

Dictionary {{RTCRtpTransceiverStats}} Members

senderId of type DOMString

The identifier of the stats object representing the {{RTCRtpSender}} associated with the {{RTCRtpTransceiver}} represented by this stats object.

receiverId of type DOMString

The identifier of the stats object representing the {{RTCRtpReceiver}} associated with the {{RTCRtpTransceiver}} represented by this stats object.

mid of type DOMString

If the {{RTCRtpTransceiver}} that this stats object represents has a {{RTCRtpTransceiver/mid}} value that is not null, this is that value, otherwise this member is not present.

RTCMediaHandlerStats dictionary

dictionary RTCMediaHandlerStats : RTCStats {
             DOMString           trackIdentifier;
             boolean             ended;
             required DOMString  kind;
};

Dictionary {{RTCMediaHandlerStats}} Members

trackIdentifier of type DOMString

Represents the id property of the track.

ended of type boolean

Reflects the ended state of the track.

kind of type DOMString

Either "audio" or "video". This reflects the kind attribute of the {{MediaStreamTrack}}, see [[!GETUSERMEDIA]].

RTCVideoHandlerStats dictionary

dictionary RTCVideoHandlerStats : RTCMediaHandlerStats {
};

Dictionary {{RTCVideoHandlerStats}} Members

RTCVideoSenderStats dictionary

An {{RTCVideoSenderStats}} object represents the stats about one video sender of a {{RTCPeerConnection}} object for which one calls {{RTCPeerConnection/getStats()}}.

It appears in the stats as soon as the sender is added by either addTrack or addTransceiver, or by media negotiation.

dictionary RTCVideoSenderStats : RTCVideoHandlerStats {
             DOMString           mediaSourceId;
};

Dictionary {{RTCVideoSenderStats}} Members

mediaSourceId of type DOMString

The identifier of the stats object representing the track currently attached to this sender, an {{RTCMediaSourceStats}}.

RTCVideoReceiverStats dictionary

An {{RTCVideoReceiverStats}} object represents the stats about one video receiver of a {{RTCPeerConnection}} object for which one calls {{RTCPeerConnection/getStats()}}.

It appears in the stats as soon as the {{RTCRtpReceiver}} is added by either {{RTCPeerConnection/addTrack()}} or {{RTCPeerConnection/addTransceiver()}}, or by media negotiation.

dictionary RTCVideoReceiverStats : RTCVideoHandlerStats {
};

Dictionary {{RTCVideoReceiverStats}} Members

RTCAudioHandlerStats dictionary

dictionary RTCAudioHandlerStats : RTCMediaHandlerStats {
};

Dictionary {{RTCAudioHandlerStats}} Members

RTCAudioSenderStats dictionary

An {{RTCAudioSenderStats}} object represents the stats about one audio sender of a {{RTCPeerConnection}} object for which one calls {{RTCPeerConnection/getStats()}}.

It appears in the stats as soon as the {{RTCRtpSender}} is added by either {{RTCPeerConnection/addTrack()}} or {{RTCPeerConnection/addTransceiver()}}, or by media negotiation.

dictionary RTCAudioSenderStats : RTCAudioHandlerStats {
             DOMString           mediaSourceId;
};

Dictionary {{RTCAudioSenderStats}} Members

mediaSourceId of type DOMString

The identifier of the stats object representing the track currently attached to this sender, an {{RTCMediaSourceStats}}.

RTCAudioReceiverStats dictionary

An {{RTCAudioReceiverStats}} object represents the stats about one audio receiver of a {{RTCPeerConnection}} object for which one calls {{RTCPeerConnection.getStats()}}.

It appears in the stats as soon as the {{RTCRtpReceiver}} is added by either {{RTCPeerConnection/addTrack()}} or {{RTCPeerConnection/addTransceiver()}}, or by media negotiation.

dictionary RTCAudioReceiverStats : RTCAudioHandlerStats {
};

Dictionary {{RTCAudioReceiverStats}} Members

RTCDataChannelStats dictionary

dictionary RTCDataChannelStats : RTCStats {
             DOMString           label;
             DOMString           protocol;
             unsigned short      dataChannelIdentifier;
             required DOMString  transportId;
             required RTCDataChannelState state;
             unsigned long       messagesSent;
             unsigned long long  bytesSent;
             unsigned long       messagesReceived;
             unsigned long long  bytesReceived;
};

Dictionary {{RTCDataChannelStats}} Members

label of type DOMString
The {{RTCDataChannel/label}} value of the {{RTCDataChannel}} object.
protocol of type DOMString
The {{RTCDataChannel/protocol}} value of the {{RTCDataChannel}} object.
dataChannelIdentifier of type unsigned short

The {{RTCDataChannel/id}} attribute of the {{RTCDataChannel}} object.

transportId of type DOMString
A [= stats object reference =] for the transport used to carry this datachannel.
state of type {{RTCDataChannelState}}
The {{RTCDataChannel/readyState}} value of the {{RTCDataChannel}} object.
messagesSent of type unsigned long

Represents the total number of API "message" events sent.

bytesSent of type unsigned long long

Represents the total number of payload bytes sent on this {{RTCDataChannel}}, i.e., not including headers or padding.

messagesReceived of type unsigned long

Represents the total number of API "message" events received.

bytesReceived of type unsigned long long

Represents the total number of bytes received on this {{RTCDataChannel}}, i.e., not including headers or padding.

RTCTransportStats dictionary

An {{RTCTransportStats}} object represents the stats corresponding to an {{RTCDtlsTransport}} and its underlying {{RTCIceTransport}}. When RTCP multiplexing is used, one transport is used for both RTP and RTCP. Otherwise, RTP and RTCP will be sent on separate transports, and {{RTCTransportStats/rtcpTransportStatsId}} can be used to pair the resulting {{RTCTransportStats}} objects. Additionally, when bundling is used, a single transport will be used for all {{MediaStreamTrack}}s in the bundle group. If bundling is not used, different {{MediaStreamTrack}} will use different transports. RTCP multiplexing and bundling are described in [[!WEBRTC]].

dictionary RTCTransportStats : RTCStats {
             unsigned long long    packetsSent;
             unsigned long long    packetsReceived;
             unsigned long long    bytesSent;
             unsigned long long    bytesReceived;
             DOMString             rtcpTransportStatsId;
             RTCIceRole            iceRole;
             DOMString             iceLocalUsernameFragment;
             required RTCDtlsTransportState dtlsState;
             RTCIceTransportState  iceState;
             DOMString             selectedCandidatePairId;
             DOMString             localCertificateId;
             DOMString             remoteCertificateId;
             DOMString             tlsVersion;
             DOMString             dtlsCipher;
             DOMString             srtpCipher;
             DOMString             tlsGroup;
             unsigned long         selectedCandidatePairChanges;
};

Dictionary {{RTCTransportStats}} Members

packetsSent of type unsigned long long

Represents the total number of packets sent over this transport.

packetsReceived of type unsigned long long

Represents the total number of packets received on this transport.

bytesSent of type unsigned long long

Represents the total number of payload bytes sent on this {{RTCIceTransport}}, i.e., not including headers, padding or ICE connectivity checks.

bytesReceived of type unsigned long long

Represents the total number of payload bytes received on this {{RTCIceTransport}}, i.e., not including headers, padding or ICE connectivity checks.

rtcpTransportStatsId of type DOMString

If RTP and RTCP are not multiplexed, this is the {{RTCStats/id}} of the transport that gives stats for the RTCP component, and this record has only the RTP component stats.

iceRole of type {{RTCIceRole}}

Set to the current value of the {{RTCIceTransport/role}} attribute of the underlying {{RTCDtlsTransport}}.{{RTCDtlsTransport/iceTransport}}.

iceLocalUsernameFragment of type DOMString

Set to the current value of the local username fragment used in message validation procedures [[RFC5245]] for this {{RTCIceTransport}}. It may be updated on setLocalDescription() and on ICE restart.

dtlsState of type {{RTCDtlsTransportState}}

Set to the current value of the {{RTCDtlsTransport/state}} attribute of the underlying {{RTCDtlsTransport}}.

iceState of type {{RTCIceTransportState}}

Set to the current value of the {{RTCIceTransport/state}} attribute of the underlying {{RTCIceTransport}}.

selectedCandidatePairId of type DOMString

It is a unique identifier that is associated to the object that was inspected to produce the {{RTCIceCandidatePairStats}} associated with this transport.

localCertificateId of type DOMString

For components where DTLS is negotiated, give local certificate.

remoteCertificateId of type DOMString

For components where DTLS is negotiated, give remote certificate.

tlsVersion of type DOMString

For components where DTLS is negotiated, the TLS version agreed. Only [= map/exist =]s after DTLS negotiation is complete.

The value comes from ServerHello.supported_versions if present, otherwise from ServerHello.version. It is represented as four upper case hexadecimal digits, representing the two bytes of the version.

dtlsCipher of type DOMString

Descriptive name of the cipher suite used for the DTLS transport, as defined in the "Description" column of the IANA cipher suite registry [[!IANA-TLS-CIPHERS]].

srtpCipher of type DOMString

Descriptive name of the protection profile used for the SRTP transport, as defined in the "Profile" column of the IANA DTLS-SRTP protection profile registry [[!IANA-DTLS-SRTP]] and described further in [[RFC5764]].

tlsGroup of type DOMString

Descriptive name of the group used for the encryption, as defined in the "Description" column of the IANA TLS Supported Groups registry [[!IANA-TLS-GROUPS]].

selectedCandidatePairChanges of type unsigned long

The number of times that the selected candidate pair of this transport has changed. Going from not having a selected candidate pair to having a selected candidate pair, or the other way around, also increases this counter. It is initially zero and becomes one when an initial candidate pair is selected.

RTCSctpTransportStats dictionary

An {{RTCSctpTransportStats}} object represents the stats corresponding to an {{RTCSctpTransport}} described in [[!WEBRTC]].

dictionary RTCSctpTransportStats : RTCStats {
            double smoothedRoundTripTime;
            unsigned long congestionWindow;
            unsigned long receiverWindow;
            unsigned long mtu;
            unsigned long unackData;
};

Dictionary {{RTCSctpTransportStats}} Members

smoothedRoundTripTime of type double

The latest smoothed round-trip time value, corresponding to spinfo_srtt defined in [[RFC6458]] but converted to seconds. If there has been no round-trip time measurements yet, this value is undefined.

congestionWindow of type unsigned long

The latest congestion window, corresponding to spinfo_cwnd defined in [[RFC6458]].

receiverWindow of type unsigned long

The latest receiver window, corresponding to sstat_rwnd defined in [[RFC6458]].

mtu of type unsigned long

The latest maximum transmission unit, corresponding to spinfo_mtu defined in [[RFC6458]].

unackData of type unsigned long

The number of unacknowledged DATA chunks, corresponding to sstat_unackdata defined in [[RFC6458]].

RTCIceCandidateStats dictionary

{{RTCIceCandidateStats}} reflects the properties of a candidate in Section 15.1 of [[!RFC5245]]. It corresponds to a {{RTCIceCandidate}} object.

dictionary RTCIceCandidateStats : RTCStats {
             required DOMString       transportId;
             DOMString?               address;
             long                     port;
             DOMString                protocol;
             required RTCIceCandidateType candidateType;
             long                     priority;
             DOMString                url;
             DOMString                relayProtocol;
};

Dictionary {{RTCIceCandidateStats}} Members

transportId of type DOMString

It is a unique identifier that is associated to the object that was inspected to produce the {{RTCTransportStats}} associated with this candidate.

address of type DOMString

It is the address of the candidate, allowing for IPv4 addresses, IPv6 addresses, and fully qualified domain names (FQDNs). See [[!RFC5245]] section 15.1 for details.

The user agent should make sure that only remote candidate addresses that the web application has configured on the corresponding {{RTCPeerConnection}} are exposed; This is especially important for peer reflexive remote candidates. By default, the user agent MUST leave the {{RTCIceCandidateStats/address}} member as null in the {{RTCIceCandidateStats}} dictionary of any remote candidate. Once a {{RTCPeerConnection}} instance learns on an address by the web application using {{RTCPeerConnection/addIceCandidate()}}, the user agent can expose the 'address' member value in any remote {{RTCIceCandidateStats}} dictionary of the corresponding {{RTCPeerConnection}} that matches the newly learnt address.

port of type long

It is the port number of the candidate.

protocol of type DOMString

Valid values for transport is one of "udp" and "tcp". Based on the "transport" defined in [[!RFC5245]] section 15.1.

relayProtocol of type DOMString

It is the protocol used by the endpoint to communicate with the TURN server. This is only present for local candidates. Valid values are "udp", "tcp", or "tls".

candidateType of type {{RTCIceCandidateType}}

This enumeration is defined in [[WEBRTC]].

priority of type long

Calculated as defined in [[!RFC5245]] section 15.1.

url of type DOMString

For local candidates this is the URL of the ICE server from which the candidate was obtained. It is the same as the {{RTCPeerConnectionIceEvent/url}} surfaced in the {{RTCPeerConnectionIceEvent}}.

For remote candidates, this property is not present.

RTCIceCandidatePairStats dictionary

dictionary RTCIceCandidatePairStats : RTCStats {
             required DOMString            transportId;
             required DOMString            localCandidateId;
             required DOMString            remoteCandidateId;
             required RTCStatsIceCandidatePairState state;
             boolean                       nominated;
             unsigned long long            packetsSent;
             unsigned long long            packetsReceived;
             unsigned long long            bytesSent;
             unsigned long long            bytesReceived;
             DOMHighResTimeStamp           lastPacketSentTimestamp;
             DOMHighResTimeStamp           lastPacketReceivedTimestamp;
             DOMHighResTimeStamp           firstRequestTimestamp;
             DOMHighResTimeStamp           lastRequestTimestamp;
             DOMHighResTimeStamp           lastResponseTimestamp;
             double                        totalRoundTripTime;
             double                        currentRoundTripTime;
             double                        availableOutgoingBitrate;
             double                        availableIncomingBitrate;
             unsigned long                 circuitBreakerTriggerCount;
             unsigned long long            requestsReceived;
             unsigned long long            requestsSent;
             unsigned long long            responsesReceived;
             unsigned long long            responsesSent;
             unsigned long long            retransmissionsReceived;
             unsigned long long            retransmissionsSent;
             unsigned long long            consentRequestsSent;
             DOMHighResTimeStamp           consentExpiredTimestamp;
             unsigned long                 packetsDiscardedOnSend;
             unsigned long long            bytesDiscardedOnSend;
             unsigned long long            requestBytesSent;
             unsigned long long            consentRequestBytesSent;
             unsigned long long            responseBytesSent;
};

Dictionary {{RTCIceCandidatePairStats}} Members

transportId of type DOMString

It is a unique identifier that is associated to the object that was inspected to produce the {{RTCTransportStats}} associated with this candidate pair.

localCandidateId of type DOMString

It is a unique identifier that is associated to the object that was inspected to produce the {{RTCIceCandidateStats}} for the local candidate associated with this candidate pair.

remoteCandidateId of type DOMString

It is a unique identifier that is associated to the object that was inspected to produce the {{RTCIceCandidateStats}} for the remote candidate associated with this candidate pair.

state of type {{RTCStatsIceCandidatePairState}}

Represents the state of the checklist for the local and remote candidates in a pair.

nominated of type boolean

Related to updating the nominated flag described in Section 7.1.3.2.4 of [[!RFC5245]].

packetsSent of type unsigned long long

Represents the total number of packets sent on this candidate pair.

packetsReceived of type unsigned long long

Represents the total number of packets received on this candidate pair.

bytesSent of type unsigned long long

Represents the total number of payload bytes sent on this candidate pair, i.e., not including headers, padding or ICE connectivity checks.

bytesReceived of type unsigned long long

Represents the total number of payload bytes received on this candidate pair, i.e., not including headers, padding or ICE connectivity checks.

lastPacketSentTimestamp of type DOMHighResTimeStamp

Represents the timestamp at which the last packet was sent on this particular candidate pair, excluding STUN packets.

lastPacketReceivedTimestamp of type DOMHighResTimeStamp

Represents the timestamp at which the last packet was received on this particular candidate pair, excluding STUN packets.

firstRequestTimestamp of type DOMHighResTimeStamp

Represents the timestamp at which the first STUN request was sent on this particular candidate pair.

lastRequestTimestamp of type DOMHighResTimeStamp

Represents the timestamp at which the last STUN request was sent on this particular candidate pair. The average interval between two consecutive connectivity checks sent can be calculated with (lastRequestTimestamp - firstRequestTimestamp) / requestsSent.

lastResponseTimestamp of type DOMHighResTimeStamp

Represents the timestamp at which the last STUN response was received on this particular candidate pair.

totalRoundTripTime of type double

Represents the sum of all round trip time measurements in seconds since the beginning of the session, based on STUN connectivity check [[!STUN-PATH-CHAR]] responses (responsesReceived), including those that reply to requests that are sent in order to verify consent [[!RFC7675]]. The average round trip time can be computed from {{totalRoundTripTime}} by dividing it by {{responsesReceived}}.

currentRoundTripTime of type double

Represents the latest round trip time measured in seconds, computed from both STUN connectivity checks [[!STUN-PATH-CHAR]], including those that are sent for consent verification [[!RFC7675]].

availableOutgoingBitrate of type double

It is calculated by the underlying congestion control by combining the available bitrate for all the outgoing RTP streams using this candidate pair. The bitrate measurement does not count the size of the IP or other transport layers like TCP or UDP. It is similar to the TIAS defined in [[!RFC3890]], i.e., it is measured in bits per second and the bitrate is calculated over a 1 second window.

Implementations that do not calculate a sender-side estimate MUST leave this undefined. Additionally, the value MUST be undefined for candidate pairs that were never used. For pairs in use, the estimate is normally no lower than the bitrate for the packets sent at {{lastPacketSentTimestamp}}, but might be higher. For candidate pairs that are not currently in use but were used before, implementations MUST return undefined.

availableIncomingBitrate of type double

It is calculated by the underlying congestion control by combining the available bitrate for all the incoming RTP streams using this candidate pair. The bitrate measurement does not count the size of the IP or other transport layers like TCP or UDP. It is similar to the TIAS defined in [[!RFC3890]], i.e., it is measured in bits per second and the bitrate is calculated over a 1 second window.

Implementations that do not calculate a receiver-side estimate MUST leave this undefined. Additionally, the value should be undefined for candidate pairs that were never used. For pairs in use, the estimate is normally no lower than the bitrate for the packets received at {{lastPacketReceivedTimestamp}}, but might be higher. For candidate pairs that are not currently in use but were used before, implementations MUST return undefined.

circuitBreakerTriggerCount of type unsigned long

Represents the number of times the circuit breaker is triggered for this particular 5-tuple. Ceasing transmission when a circuit breaker is triggered is defined in Section 4.5 of [[!RFC8083]]. The field MUST return undefined for user-agents that do not implement the circuit-breaker algorithm.

requestsReceived of type unsigned long long

Represents the total number of connectivity check requests received (including retransmissions). It is impossible for the receiver to tell whether the request was sent in order to check connectivity or check consent, so all connectivity checks requests are counted here.

requestsSent of type unsigned long long

Represents the total number of connectivity check requests sent (not including retransmissions).

responsesReceived of type unsigned long long

Represents the total number of connectivity check responses received.

responsesSent of type unsigned long long

Represents the total number of connectivity check responses sent. Since we cannot distinguish connectivity check requests and consent requests, all responses are counted.

retransmissionsReceived of type unsigned long long

Represents the total number of connectivity check request retransmissions received. Retransmissions are defined as connectivity check requests with a TRANSACTION_TRANSMIT_COUNTER attribute where the "req" field is larger than 1, as defined in [[!RFC7982]].

retransmissionsSent of type unsigned long long

Represents the total number of connectivity check request retransmissions sent.

consentRequestsSent of type unsigned long long

Represents the total number of consent requests sent.

consentExpiredTimestamp of type DOMHighResTimeStamp

Represents the timestamp at which the latest valid STUN binding response expired, as defined in [[!RFC7675]] section 5.1. If a valid STUN binding response has not been made ({{responsesReceived}} is zero) or the latest one has not expired this value must be undefined.

packetsDiscardedOnSend of type unsigned long

Total number of packets for this candidate pair that have been discarded due to socket errors, i.e. a socket error occured when handing the packets to the socket. This might happen due to various reasons, including full buffer or no available memory.

bytesDiscardedOnSend of type unsigned long long

Total number of bytes for this candidate pair that have been discarded due to socket errors, i.e. a socket error occured when handing the packets containing the bytes to the socket. This might happen due to various reasons, including full buffer or no available memory. Calculated as defined in [[!RFC3550]] section 6.4.1.

requestBytesSent of type unsigned long long

Total number of bytes sent for connectivity checks.

consentRequestBytesSent of type unsigned long long

Total number of bytes sent for consent requests.

responseBytesSent of type unsigned long long

Total number of bytes sent for connectivity check responses.

RTCStatsIceCandidatePairState enum

enum RTCStatsIceCandidatePairState {
    "frozen",
    "waiting",
    "in-progress",
    "failed",
    "succeeded"
};
Enumeration description
frozen

Defined in Section 5.7.4 of [[!RFC5245]].

waiting

Defined in Section 5.7.4 of [[!RFC5245]].

in-progress

Defined in Section 5.7.4 of [[!RFC5245]].

failed

Defined in Section 5.7.4 of [[!RFC5245]].

succeeded

Defined in Section 5.7.4 of [[!RFC5245]].

RTCCertificateStats dictionary

dictionary RTCCertificateStats : RTCStats {
             required DOMString fingerprint;
             required DOMString fingerprintAlgorithm;
             required DOMString base64Certificate;
             DOMString issuerCertificateId;
};

Dictionary {{RTCCertificateStats}} Members

fingerprint of type DOMString

The fingerprint of the certificate. Only use the fingerprint value as defined in Section 5 of [[!RFC4572]].

fingerprintAlgorithm of type DOMString

The hash function used to compute the certificate fingerprint. For instance, "sha-256".

base64Certificate of type DOMString

The DER-encoded base-64 representation of the certificate.

issuerCertificateId of type DOMString

The {{issuerCertificateId}} refers to the stats object that contains the next certificate in the certificate chain. If the current certificate is at the end of the chain (i.e. a self-signed certificate), this will not be set.

RTCIceServerStats dictionary

dictionary RTCIceServerStats : RTCStats {
             required DOMString url;
             long port;
             DOMString relayProtocol;
             unsigned long totalRequestsSent;
             unsigned long totalResponsesReceived;
             double totalRoundTripTime;
  };

Dictionary {{RTCIceServerStats}} Members

url of type DOMString

The URL of the ICE server (e.g. TURN or STUN server).

port of type long

It is the port number used by the client.

relayProtocol of type DOMString

It is the protocol used by the endpoint to communicate with the ICE server. Valid values are udp, tcp, or tls as defined in {{RTCIceCandidateStats}}. This is the same value that is used for the relay protocol of local ICE candidates.

totalRequestsSent of type unsigned long

The total amount of requests that have been sent to this server.

totalResponsesReceived of type unsigned long

The total amount of responses received from this server.

totalRoundTripTime of type double

The sum of RTTs for all requests that have been sent where a response has been received.

Obsolete stats

Obsolete {{RTCMediaStreamStats}} members

dictionary RTCMediaStreamStats : RTCStats {
  DOMString streamIdentifier;
  sequence<DOMString> trackIds;
};

This entire dictionary was made obsolete in September, 2019 due to sender, receiver and transceiver stats objects being a better fit to describe the modern {{RTCPeerConnection}} model (Unified Plan).

streamIdentifier of type DOMString

stream.id property

trackIds of type sequence<DOMString>

This is the {{RTCStats/id}} of the stats object, not the track.id.

Obsolete RTCSenderVideoTrackAttachmentStats dictionary

An RTCSenderVideoTrackAttachmentStats object represents the stats about one attachment of a video MediaStreamTrack to the RTCPeerConnection object for which one calls getStats.

It appears in the stats as soon as it is attached (via addTrack, via addTransceiver, via replaceTrack on an RTCRtpSender object).

If a video track is attached twice (via addTransceiver or replaceTrack), there will be two RTCSenderVideoTrackAttachmentStats objects, one for each attachment. They will have the same "trackIdentifier" member, but different "id" members.

This dictionary was made obsolete after its members were moved to "media-source", "sender" and "outbound-rtp" (to enable simulcast stats) and the "onstatsended" event was removed, making the "track" stats redundant.

dictionary RTCSenderVideoTrackAttachmentStats : RTCVideoSenderStats {
};

Obsolete RTCSenderAudioTrackAttachmentStats dictionary

An RTCSenderAudioTrackAttachmentStats object represents the stats about one attachment of an audio MediaStreamTrack to the RTCPeerConnection object for which one calls getStats.

It appears in the stats as soon as it is attached (via addTrack, via addTransceiver, via replaceTrack on an RTCRtpSender object).

If an audio track is attached twice (via addTransceiver or replaceTrack), there will be two RTCSenderAudioTrackAttachmentStats objects, one for each attachment. They will have the same "trackIdentifier" member, but different "id" members.

This dictionary was made obsolete after its members were moved to "media-source", "sender" and "outbound-rtp" (to enable simulcast stats) and the "onstatsended" event was removed, making the "track" stats redundant.

dictionary RTCSenderAudioTrackAttachmentStats : RTCAudioSenderStats {
};

Obsolete {{RTCReceiverVideoTrackAttachmentStats}} dictionary

The {{RTCReceiverVideoTrackAttachmentStats}} is a copy of {{RTCVideoReceiverStats}}. It adds no new information, it only exists for backwards-compatibility reasons as an obsolete dictionary.

dictionary RTCReceiverVideoTrackAttachmentStats : RTCVideoReceiverStats {};

Obsolete {{RTCReceiverAudioTrackAttachmentStats}} dictionary

The {{RTCReceiverAudioTrackAttachmentStats}} is a copy of RTCAudioReceiverStats. It adds no new information, it only exists for backwards-compatibility reasons as an obsolete dictionary.

dictionary RTCReceiverAudioTrackAttachmentStats : RTCAudioReceiverStats {};

Obsolete {{RTCCodecStats}} members

partial dictionary RTCCodecStats {
    DOMString implementation;
};
          
implementation of type DOMString

This was moved to {{RTCInboundRtpStreamStats}}.{{RTCInboundRtpStreamStats}}/decoderImplementation}} and {{RTCOutboundRtpStreamStats}}.{{RTCOutboundRtpStreamStats/encoderImplementation}} in August 2019.

Obsolete {{RTCIceCandidateStats}} members

partial dictionary RTCIceCandidateStats {
    boolean deleted = false;
    boolean isRemote;
};
        
deleted of type boolean

This field was obsoleted because if the ICE candidate is deleted it no longer appears in {{RTCPeerConnection/getStats()}}.

isRemote of type boolean

false indicates that this represents a local candidate; true indicates that this represents a remote candidate.

Obsolete {{RTCIceCandidatePairStats}} members

partial dictionary RTCIceCandidatePairStats {
    double totalRtt;
    double currentRtt;
    unsigned long long priority;
};
        
totalRtt

This field got renamed to {{totalRoundTripTime}} in Dec 2016.

currentRtt

This field got renamed to {{currentRoundTripTime}} in Dec 2016.

priority

This field got removed in Feb 2018, as it cannot be represented in 53 bits. It can be recalculated if needed as defined in [[RFC5245]] section 5.7.2.

Obsolete {{RTCRtpStreamStats}} members

partial dictionary RTCRtpStreamStats {
    DOMString mediaType;
    double averageRTCPInterval;
};
mediaType of type DOMString

This field got renamed to {{kind}} in Feb 2018.

averageRTCPInterval

This field got renamed to {{averageRtcpInterval}} in Jan 2018.

Obsolete {{RTCInboundRtpStreamStats}} members

partial dictionary RTCInboundRtpStreamStats {
    DOMString trackId;
    double fractionLost;
};
trackId of type DOMString

The identifier of the stats object representing the receiving track, an {{RTCReceiverAudioTrackAttachmentStats}} or {{RTCReceiverVideoTrackAttachmentStats}}.

This field was made obsolete in April 2020 as a follow-up to "track" stats having been made obsolete.

fractionLost of type double

This field was moved to {{RTCRemoteInboundRtpStreamStats}} in December 2017.

Obsolete {{RTCOutboundRtpStreamStats}} members

partial dictionary RTCOutboundRtpStreamStats {
    DOMString trackId;
};
trackId of type DOMString

The identifier of the stats object representing the current track attachment to the sender of this stream, an {{RTCSenderAudioTrackAttachmentStats}} or {{RTCSenderVideoTrackAttachmentStats}}.

This field was made obsolete in April 2020 as a follow-up to "track" stats having been made obsolete.

Obsolete {{RTCMediaHandlerStats}} members

partial dictionary RTCMediaHandlerStats {
    RTCPriorityType     priority;
    boolean             remoteSource;
};
        
priority of type {{RTCPriorityType}}

Indicates the priority that has been set for the track. It is defined in [[RTCWEB-TRANSPORT]], Section 4, but was removed from [[WEBRTC]] due to lack of implementation and moved to [[WEBRTC-PRIORITY]], with some changes to its definition.

remoteSource of type boolean

Only applicable for {{RTCStatsType/"track"}} stats. true if the track attachment is on an {{RTCRtpSender}}, false if the track attachment is on an {{RTCRtpReceiver}}.

This was originally defined as {{RTCMediaSourceStats/relayedSource}} but implementations had implemented it according to this current definition. With "track" stats made obsolete, and this information being available elsewhere, this metric was made obsolete in April, 2020.

Obsolete {{RTCAudioHandlerStats}} members

partial dictionary RTCAudioHandlerStats {
    double audioLevel;
    double totalAudioEnergy;
    double totalSamplesDuration;
    boolean voiceActivityFlag;
};
audioLevel of type double

This field was moved to {{RTCAudioReceiverStats}} and {{RTCAudioSourceStats}} in June 2019.

totalAudioEnergy of type double

This field was moved to {{RTCAudioReceiverStats}} and {{RTCAudioSourceStats}} in June 2019.

totalSamplesDuration of type double

This field was moved to {{RTCAudioReceiverStats}} and {{RTCAudioSourceStats}} in June 2019.

voiceActivityFlag of type boolean

This field was moved to {{RTCOutboundRtpStreamStats}} and {{RTCInboundRtpStreamStats}} in August 2019.

Obsolete {{RTCAudioSenderStats}} members

partial dictionary RTCAudioSenderStats {
    unsigned long long totalSamplesSent;
    double echoReturnLoss;
    double echoReturnLossEnhancement;
};
totalSamplesSent of type unsigned long long

This was moved to {{RTCOutboundRtpStreamStats}} in August 2019.

echoReturnLoss of type double

This was moved to {{RTCAudioSourceStats}} in August 2019.

echoReturnLossEnhancement of type double

This was moved to {{RTCAudioSourceStats}} in August 2019.

Obsolete {{RTCAudioReceiverStats}} members

partial dictionary RTCAudioReceiverStats {
    DOMHighResTimeStamp estimatedPlayoutTimestamp;
    double jitterBufferDelay;
    unsigned long long jitterBufferEmittedCount;
    unsigned long long totalSamplesReceived;
    unsigned long long concealedSamples;
    unsigned long long silentConcealedSamples;
    unsigned long long concealmentEvents;
    unsigned long long insertedSamplesForDeceleration;
    unsigned long long removedSamplesForAcceleration;
    double audioLevel;
    double totalAudioEnergy;
    double totalSamplesDuration;
};
estimatedPlayoutTimestamp of type DOMHighResTimeStamp

This was moved to {{RTCInboundRtpStreamStats}} in August 2019.

jitterBufferDelay of type double

This was moved to {{RTCInboundRtpStreamStats}} in August 2019.

jitterBufferEmittedCount of type unsigned long long

This was moved to {{RTCInboundRtpStreamStats}} in August 2019.

totalSamplesReceived of type unsigned long long

This was moved to {{RTCInboundRtpStreamStats}} in August 2019.

concealedSamples of type unsigned long long

This was moved to {{RTCInboundRtpStreamStats}} in August 2019.

silentConcealedSamples of type unsigned long long

This was moved to {{RTCInboundRtpStreamStats}} in August 2019.

concealmentEvents of type unsigned long long

This was moved to {{RTCInboundRtpStreamStats}} in August 2019.

insertedSamplesForDeceleration of type unsigned long long

This was moved to {{RTCInboundRtpStreamStats}} in August 2019.

removedSamplesForAcceleration of type unsigned long long

This was moved to {{RTCInboundRtpStreamStats}} in August 2019.

audioLevel of type double

This was moved to {{RTCInboundRtpStreamStats}} in August 2019.

totalAudioEnergy of type double

This was moved to {{RTCInboundRtpStreamStats}} in August 2019.

totalSamplesDuration of type double

This was moved to {{RTCInboundRtpStreamStats}} in August 2019.

Obsolete {{RTCVideoHandlerStats}} members

partial dictionary RTCVideoHandlerStats {
    unsigned long frameWidth;
    unsigned long frameHeight;
    double framesPerSecond;
};
frameWidth of type unsigned long

This was moved to {{RTCOutboundRtpStreamStats}} and {{RTCInboundRtpStreamStats}} in August 2019.

frameHeight of type unsigned long

This was moved to {{RTCOutboundRtpStreamStats}} and {{RTCInboundRtpStreamStats}} in August 2019.

framesPerSecond of type double

For the sending case, this was replaced by {{RTCVideoSourceStats}}.{{RTCVideoSourceStats/framesPerSecond}} in May 2019 representing the frame rate of the track. For the receiving case, this was moved to {{RTCInboundRtpStreamStats}} in August 2019 representing the decoding frame rate. In August 2019, {{RTCOutboundRtpStreamStats/framesPerSecond}} was also added to {{RTCOutboundRtpStreamStats}}, representing the encoding frame rate (which may be lower than the source frame rate).

Obsolete {{RTCVideoSenderStats}} members

partial dictionary RTCVideoSenderStats {
    unsigned long keyFramesSent;
    unsigned long framesCaptured;
    unsigned long framesSent;
    unsigned long hugeFramesSent;
};
keyFramesSent of type unsigned long

This field was replaced by {{RTCOutboundRtpStreamStats/keyFramesEncoded}} in {{RTCOutboundRtpStreamStats}} in June 2019. There were no known implementations supporting the old field at the time of the change.

framesCaptured of type unsigned long

This was replaced by {{RTCVideoSourceStats}}.frames in May 2019.

framesSent of type unsigned long

This was moved to {{RTCOutboundRtpStreamStats}} in August 2019.

hugeFramesSent of type unsigned long

This was moved to {{RTCOutboundRtpStreamStats}} in August 2019.

Obsolete {{RTCVideoReceiverStats}} members

partial dictionary RTCVideoReceiverStats {
    unsigned long keyFramesReceived;
    DOMHighResTimeStamp estimatedPlayoutTimestamp;
    double jitterBufferDelay;
    unsigned long long jitterBufferEmittedCount;
    unsigned long framesReceived;
    unsigned long framesDecoded;
    unsigned long framesDropped;
    unsigned long partialFramesLost;
    unsigned long fullFramesLost;
};
keyFramesReceived of type unsigned long

This field was replaced by {{RTCInboundRtpStreamStats/keyFramesDecoded}} in {{RTCInboundRtpStreamStats}} in June 2019. There were no known implementations supporting the old field at the time of the change.

estimatedPlayoutTimestamp of type DOMHighResTimeStamp

This was moved to {{RTCInboundRtpStreamStats}} in August 2019.

jitterBufferDelay of type double

This was moved to {{RTCInboundRtpStreamStats}} in August 2019.

jitterBufferEmittedCount of type unsigned long long

This was moved to {{RTCInboundRtpStreamStats}} in August 2019.

framesReceived of type unsigned long

This was moved to {{RTCInboundRtpStreamStats}} in August 2019.

framesDecoded of type unsigned long

This was moved to {{RTCInboundRtpStreamStats}} in August 2019.

framesDropped of type unsigned long

This was moved to {{RTCInboundRtpStreamStats}} in August 2019.

partialFramesLost of type unsigned long

This was moved to {{RTCInboundRtpStreamStats}} in August 2019.

fullFramesLost of type unsigned long

This was moved to {{RTCInboundRtpStreamStats}} in August 2019.

Examples

Example of a stats application

Consider the case where the user is experiencing bad sound and the application wants to determine if the cause of it is packet loss. The following example code might be used:

var baselineReport, currentReport;
var sender = pc.getSenders()[0];

sender.getStats().then(function (report) {
    baselineReport = report;
})
.then(function() {
    return new Promise(function(resolve) {
        setTimeout(resolve, aBit); // ... wait a bit
    });
})
.then(function() {
    return sender.getStats();
})
.then(function (report) {
    currentReport = report;
    processStats();
})
.catch(function (error) {
  console.log(error.toString());
});

function processStats() {
    // compare the elements from the current report with the baseline
    for (let now of currentReport.values()) {
        if (now.type != "outbound-rtp")
            continue;

        // get the corresponding stats from the baseline report
        let base = baselineReport.get(now.id);

        if (base) {
            remoteNow = currentReport[now.remoteId];
            remoteBase = baselineReport[base.remoteId];

            var packetsSent = now.packetsSent - base.packetsSent;
            var packetsReceived = remoteNow.packetsReceived - remoteBase.packetsReceived;

            // if intervalFractionLoss is > 0.3, we've probably found the culprit
            var intervalFractionLoss = (packetsSent - packetsReceived) / packetsSent;
        }
    });
}

Security and Privacy Considerations

The data exposed by WebRTC Statistics include most of the media and network data also exposed by [[!GETUSERMEDIA]] and [[!WEBRTC]] - as such, all the privacy and security considerations of these specifications related to data exposure apply as well to this specifciation.

In addition, the properties exposed by {{RTCReceivedRtpStreamStats}}, {{RTCRemoteInboundRtpStreamStats}}, {{RTCSentRtpStreamStats}}, {{RTCOutboundRtpStreamStats}}, {{RTCRemoteOutboundRtpStreamStats}}, {{RTCIceCandidatePairStats}}, {{RTCTransportStats}} expose network-layer data not currently available to the JavaScript layer.

Beyond the risks associated with revealing IP addresses as discussed in the WebRTC 1.0 specification, some combination of the network properties uniquely exposed by this specification can be correlated with location.

For instance, the round-trip time exposed in {{RTCRemoteInboundRtpStreamStats}} can give some coarse indication on how far aparts the peers are located, and thus, if one of the peer's location is known, this may reveal information about the other peer.

When applied to isolated streams, media metrics may allow an application to infer some characteristics of the isolated stream, such as if anyone is speaking (by watching the {{RTCAudioSourceStats/audioLevel}} statistic).

The following stats are deemed to be sensitive, and MUST NOT be reported for an isolated media stream:

Acknowledgements

The editors wish to thank the Working Group chairs, Stefan Håkansson, and the Team Contact, Dominique Hazaël-Massieux, for their support. The editors would like to thank Bernard Aboba, Taylor Brandstetter, Henrik Boström, Jan-Ivar Bruaroey, Karthik Budigere, Cullen Jennings, and Lennart Schulte for their contributions to this specification.