WebRTC Stats

WebRTC Stats helps you with everything related to getting and parsing the stats for your app's WebRTC PeerConnections. On top of handling getting the stats for each peer in the call it also offers a parsed object that better helps you understand what's happening with the connection.

WebRTC Stats is using EventEmitter to fire events that you can listen to in your app.

The library is heavily inspired by @fippo's work on a similar library.

Migrating from v1

To see the changes that appeared in V2 see the changelog

How it works

The main idea of WebRTC Stats is to offer an easy way to read stats from RTCPeerConnections. It helps with gathering the stats and has a pretty helpful object that helps you understand how that connection is going.

On top of that, it offers the timeline which is a list of events gathered from the RTC connections that will definitely help you with debugging. These are optional, but by wrapping methods like getUserMedia, createOffer, addTrack, etc. you get a clear picture of what happened.

Install

npm install @peermetrics/webrtc-stats

Usage

Loading the module

WebRTC Stats can be loaded as an ES6 module, node module or directly in the browser.

After loading the module, initialize it. See Options for all the initialize options

let stats = new WebRTCStats({
    getStatsInterval: 5000
})

Add event listeners for stats:

stats.on('stats', (ev) => {
    console.log('stats', ev)
})

Use addPeer to add peers to the list of monitored peers:

let pc1 = new RTCPeerConnection({...})
stats.addPeer({
    pc: pc1,
    peerId: '1' # any string/int that helps you identify this peer
})

Now every 5000 ms WebRTC Stats will fire the stats event which will come with the object:

{
    event: 'stats',
    tag: 'stats',
    peerId: '1',
    timestamp: 'Sun Mar 22 2020 18:02:02', # a timestamp when this was fired
    data: {...}, # an object created after parsing the stats
    rawStats: RTCStatsReport, # the actual RTCStatsReport results from `getStats()`
    statsObject: {}, # an object created from RTCStatsReport that uses the `id` for each report as a key
    filteredStats: {}, # same as statsObject but with some report types filtered out (eg: `codec`, `certificate`)
}

Options

The module accepts the following options when initialized:

let stats = new WebRTCStats({
    # the interval in ms of how often we should get stats
    getStatsInterval: 5000, # Default: 1000

    # if we should include the original RTCStatsReport map when firing the `stats` event
    rawStats: false, # Default: false

    # include an object that resulted from transforming RTCStatsReport into an oject (`report.id` as the key)
    statsObject: true, # Default: false
    
    # if we should filter out some stats
    filteredStats: false, # Default: false
    
    # If we should wrap the `geUserMedia` calls so we can gather events when the methods is called or success/error
    wrapGetUserMedia: false, # Default: false
    
    # If turned on, calls `console.log`
    debug: false, # Default: false
})

API

.addPeer(options)

Adds a peer to the watch list. options

• pc: the RTCPeerConnection instance
• peerId: String/Int a unique Id to identify this peer Monitoring of a peer will automatically end when the connection is closed.

.getTimeline([filter])

Return the array of events from the timeline up to that point. If the optional filter string is present it will filter out events. Possible values: peer, connection, track, stats, getUserMedia

Events

The module uses EventEmitter to emit events. You can listen to them using .on()

stats.on('eventName', (ev) => {
})

ev will have the following structure:

{
    # The event name. Usually the method called (addTrack, createAnswer)
    event: '', 
    # The tag for this event. `stats`, `sdp`, `getUserMedia`, etc
    tag: '',
    # The id for the peer that fired this event
    peerId: '',
    # A timestamp for when the event happened
    timestamp: '',
    # Data for each event type
    data: {},
    
    # The following attrs appear at certain times
    # The error that appeared in the method we were watching
    error: {},
    # These appear on the `stats` event
    rawStats: {},
    statsObject: {},
    filteredStats: {}
}

List of fired events

Some events are not fired if for example wrapLegacyGetUserMedia and wrapRTCPeerConnection are false.

• timeline: this will fire when something has been added to the timeline.
• stats: fired for each peer when we've collected stats for it
• getUserMedia: when getUserMedia is called initially
• peer: when a peer was added
• track: a track event: addTrack, removeTrack, mute, unmute, overconstrained
• connection: any event related to connection
• datachannel: any datachannel event

License

MIT

Sponsorship

Platform testing is generously offered by BrowserStack