WEBRTC METRICS & STATS
WebRTCMetrics is a JavaScript library that aggregates stats received from several RTCPeerConnection
objects and
generates JSON reports in live during a call as well as a Call Detail Records (CDR) at the end of the call resuming
the main statistics captured.
WebRTCMetrics is based on the WebRTC getStats
API and collect statistics using probes. Each probe is
associated to a RTCPeerConnection
. A probe collects statistics from all streams of a RTCPeerConnection
.
Install
Using NPM
$ npm install webrtcmetrics
Using Yarn
$ yarn add webrtcmetrics
Usage
Create a new instance
A new instance of the WebRTCMetrics is created when calling the constructor. A JSON configuration can be set to define
the main characteristics of the collect of the statistics.
import WebRTCMetrics from "webrtcmetrics";
const configuration = {
refreshEvery: 3000,
startAfter: 5000,
stopAfter: 30000,
verbose: false,
silent: true,
};
const metrics = new WebRTCMetrics(configuration);
As defined in that sample, the following parameters can be configured:
-
refreshEvery
: Number. Contains the duration to wait (in milliseconds) before collecting a new set of statistics.
Default value is 2000.
-
startAfter
: Number. Contains the duration to wait (in milliseconds) before collecting the first set of statistics.
Default value is equals to 0 for starting immediately.
-
stopAfter
: Number. Contains the duration to wait (in milliseconds) before stopping to collect the statistics. This
duration starts after the startAfter
duration. Default value is -1 which means that the statistics are collected
until the function stop()
is called.
-
verbose
: Boolean. True for displaying verbose information in the logger such as the raw statistics coming
from getStats
. Default is false.
-
silent
: Boolean. True to disable logs. When silent
is set to true
, the parameter verbose
becomes obsolete.
Note: The configuration parameter is optional.
Create a new probe
A probe collects the statistics associated to a RTCPeerConnection
.
To create a new probe, call the function createProbe()
with a RTCPeerConnection
instance to capture.
import WebRTCMetrics from "webrtcmetrics";
const existingPeerConnection = new RTCPeerConnection(config);
const metrics = new WebRTCMetrics();
const probe = metrics.createProbe(existingPeerConnection, {
pname: 'PeerConnection_1',
cid: 'call007984',
uid: 'jdoe@mycorp.com',
ticket: true,
record: true,
passthrough: { "inbound-rtp": ["audioLevel"] }
});
Note: The RTCPeerConnection
parameter is mandatory whereas the configuration
parameter is optional.
createProbe(peerConnection
:
RTCPeerConnection, configuration ? : Object
):
Probe
The configuration
parameter contains the following properties:
-
pname
: String. Contains the name of the RTCPeerConnection
. This is an arbitrary name that can be used to identify
statistics received.
-
cid
: String. Contains the identifier of the call. This is an arbitrary name that can be used to gather the
statistics.
-
uid
: String. Contains the identifier of the user. This is an arbitrary name that can be used to gather the
statistics.
-
ticket
: Boolean. True for generating a ticket when the collect of statistics is stopped. Default is true.
-
record
: Boolean. True to link all reports generated to the ticket. This allows to access to all reports individually
after the call. Default is false.
Probe lifecycle
Once a probe has been created, it is ready to collect the statistics using reports. The application needs to listen
to the event onreport
to receive them.
After the call, a ticket that summarizes all the reports received for a probe can be received by listening to the
event onticket
. Don't forget to put the property ticket
to true in the configuration of the WebRTCMetrics
Object.
Complete example
const probe = metrics.createProbe(existingPeerConnection, {
pname: 'PeerConnection_1',
cid: 'call007984',
uid: 'jdoe@mycorp.com',
ticket: true,
record: true,
});
probe.onreport = (report) => {
};
probe.onticket = (ticket) => {
};
metrics.onresult = (result) => {
}
metrics.startAllProbes();
probe.updateUserId('newUserID');
probe.updateCallId('newCallID');
if (metrics.running) {
metrics.stopAllProbes();
}
Additional information
The reports can be obtained by registering to event onreport
; this callback is called in loop with an interval equals
to the value of the refreshEvery
parameter and with the report generated.
If you don't want to capture the first curve of statistics but something much more linear, you can specify a delay
before receiving the metrics. By default, the stats are captured immediately. But depending on your needs, use the
parameter startAfter
to delay the capture.
Stats can be captured during a defined period or time. To do that, set a value to the parameter stopAfter
to stop
receiving reports after that duration given in ms. If you want to capture statistics as long as the call is running,
omit that parameter of set the value to -1
. In that case, you will have to call manually the method stop()
of the
probe to stop the collector.
The first set of statistics collected (first report) is called the reference report. It is reported separately from
the others (can't be received in the onreport
event) but is used for computing statistics of the next ones (for
example delta_packets_received).
Note: The report
and ticket
parameters received from the events are JSON objects. See below for the content.
Dealing with multiple streams in a probe
A RTCPeerConnection
can transport more than one audio and video streams (MediaStreamTrack
). Statistics is collected
per type of stream (audio or video) and per direction (inbound or outbound).
Each report contains the statistics of all streams in live. Ticket summarizes the statistics of all streams at the end
of the call.
Creating multiples probes
When connecting to a conference server such as an SFU, you can receive multiple RTCPeerConnection
objects. You can
collect statistics from each by creating as many probes as needed. One for each RTCPeerConnection
.
As the parameter refreshEvery, startAfter and stopAfter are common to all probes created, the statistics of
all probes are collected one after the other, as soon as possible in order to be able to compare. To avoid any mistake,
each probe has its own timestamp
when the stats have been collected.
const probe1 = metrics.createProbe(pc1, {
pname: 'pc_1',
ticket: true,
record: true,
});
const probe2 = metrics.createProbe(pc2, {
pname: 'pc_2',
ticket: true,
record: true,
});
probe1.onticket = (result) => {
}
probe2.onticket = (result) => {
}
metrics.startAllProbes();
Collecting stats from all probes
Register to the event onresult
from the metrics Object created to get a global report that contains all probes reports
as well as some global stats.
Note: This method is equivalent to register to the event onreport
on each probe individually.
Report Statistics
Each report collected from the event onreport
contains the following statistics.
Global statistics
Name | Value | Description |
---|
pname | String | Name of the Peer Connection given |
call_id | String | Identifier or abstract name representing the call |
user_id | String | Identifier or abstract name representing the user |
timestamp | Number | Timestamp of the metric collected |
count | Number | Number of the report |
Audio statistics
Audio statistics are gathered under the audio
properties which is an object containing all the audio streams
collected (inbound and outbound). Each stream is identified by its ssrc
.
Each inbound audio stream contains the following statistics:
Name | Value | Description |
---|
codec_in | JSON | Description of the audio input codec and parameters used |
codec_id_in | String | ID of the audio input codec used |
delta_KBytes_in | Number | Number of kilobytes (KB) received since the last report |
delta_kbs_in | Number | Number of kilobits received per second since the last report |
delta_jitter_ms_in | Number | Incoming Jitter (in ms) |
delta_packets_lost_in | Number | Number of packets lost (not received) since last report |
delta_packets_in | Number | Number of packets received since the last report |
delta_rtt_ms_in | Number | Round Trip-Time (in ms). Could be null when no value collected. |
delta_synthetized_ms_in | Number | Duration of synthetized voice since last report (in ms) |
delta_playout_delay_ms_in | Number | Delay of the playout path since last report (in ms) |
delta_jitter_buffer_delay_ms_in | Number | Average Jitter buffer delay (in ms) |
direction | String | Direction of the stream. "inbound" here. |
level_in | Number | Level of the input sound. Detect presence of incoming sound |
mos_emodel_in | Number | Audio quality indicator based on 'MOS E-Model ITU-T G.107.2 (Fullband E-model)' |
mos_in | Number | Audio quality indicator based on 'Effective Latency' or 'Codec fitting parameters' |
percent_packets_lost_in | Number | Percent of audio packet lost (not received) since the last report |
percent_synthetized_in | Number | Percent of voice packet synthetized (generated) since the last report |
timestamp_in | Number | Timestamp when report has been sent. Associated with delta_rtt_ms_in, total_rtt_measure_in and total_rtt_ms_in |
total_KBytes_in | Number | Number of kilobytes (KB) received since the beginning of the call |
total_packets_lost_in | Number | Number of packets lost (not received) since the beginning of the call |
total_packets_in | Number | Number of packets received since the beginning of the call |
total_rtt_measure_in | Number | Number of RTT measurements done |
total_rtt_ms_in | Number | Total Round Trip Time since the beginning of the call |
total_playout_ms_in | Number | Total duration of the playout since the beginning of the call (in ms) |
total_synthetized_ms_in | Number | Total duration of the synthetized voice since the beginning of the call (in ms) |
total_percent_synthetized_in | Number | Percent of voice packet synthetized (generated) since the beginning of the call |
total_time_jitter_buffer_delay_in | Number | Total time spent by all audio samples in jitter buffer (in ms) |
total_jitter_emitted_in | Number | Total number of audio samples that have come out the jitter buffer (in ms) |
track_in | String | The id of the associated mediastream track |
Note: mos_emodel_in
and mos_in
reflects the quality of the audio media received using a rank from 0 (inaudible) to
4.5 (excellent). It is the quality the local user experienced from his call.
Each outbound audio stream contains the following statistics
Name | Value | Description |
---|
active_out | Boolean | True if that stream is active (sending media) |
codec_out | JSON | Description of the audio output codec and parameters used |
codec_id_out | String | ID of the audio output codec used |
delta_packet_delay_ms_out | Number | Average duration spent by packets before being sent (in ms) |
delta_KBytes_out | Number | Number of kilobytes (KB) sent since last report |
delta_kbs_out | Number | Number of kbits sent per second since the last report |
delta_jitter_ms_out | Number | Outgoing Jitter (in ms) |
delta_packets_lost_out | Number | Number of packets lost (not received by the recipient) since last report |
delta_packets_out | Number | Number of packets sent since the last report |
delta_rtt_ms_out | Number | Round Trip-Time (in ms). Could be null when no value collected. |
direction | String | Direction of the stream. "outbound" here. |
level_out | Number | Level of the output sound. Detect presence of outgoing sound |
mos_emodel_out | Number | Audio quality indicator based on 'MOS E-Model ITU-T G.107.2 (Fullband E-model)' |
mos_out | Number | Audio quality indicator based on 'Effective Latency' or 'Codec fitting parameters' |
percent_packets_lost_out | Number | Percent of audio packet lost (not received by the recipient) since the last report |
timestamp_out | Number | Timestamp when report has been received. Associated with delta_jitter_ms_out and delta_rtt_ms_out |
total_KBytes_out | Number | Number of kilobytes (KB) sent since the beginning of the call |
total_time_packets_delay_out | Number | Total time spent for all packets before being sent (in ms) |
total_packets_lost_out | Number | Number of packets lost (not received by the recipient) since the beginning of the call |
total_packets_out | Number | Number of packets sent since the beginning of the call |
total_rtt_measure_out | Number | Number of RTT measurements done |
total_rtt_ms_out | Number | Total Round Trip Time since the beginning of the call |
track_out | String | The id of the mediastream track associated |
device_out | String | The label of the device associated to the track_out |
Note: mos_emodel_out
and mos_out
reflects the quality of the audio media sent using a rank from 0 (inaudible) to
4.5 (excellent). It is not the quality the remote peer will experience but is a good indicator of the capacity of the
local user to send the media to detect a quality issue on the local side
Video statistics
Video statistics are gathered under the video
properties which is an object containing all the video streams
collected (inbound and outbound). Each stream is identified by its ssrc
.
Each inbound video stream contains the following statistics:
Name | Value | Description |
---|
decoder_in | String | Description of the video decoder used |
delta_KBytes_in | Number | Number of kilobytes (KB) received since the last report |
delta_kbs_in | Number | Number of kbits received per second since the last report |
delta_jitter_ms_in | Number | Incoming Jitter (in ms). Could be null when no value collected |
delta_glitch_in | JSON | Number of freezes and pauses encountered since the last report |
delta_decode_frame_ms_in | Number | Time needed to decode a frame (in ms) |
delta_processing_delay_ms_in | Number | Time needed to process a frame (in ms) |
delta_assembly_delay_ms_in | Number | Time needed to assemble a frame (in ms) |
delta_jitter_buffer_delay_ms_in | Number | Average Jitter buffer delay (in ms) |
delta_nack_sent_in | Number | Nack sent since the last report |
delta_packets_lost_in | Number | Number of packets lost (not received) since last report |
delta_packets_in | Number | Number of packets received since the last report |
delta_pli_sent_in | Number | Pli sent since the last report |
codec_in | JSON | Description of the video input codec and parameters used |
codec_id_in | String | ID of the video input codec used |
size_in | Number | Size of the input video (from remote peer) + framerate |
percent_packets_lost_in | Number | Percent of audio packet lost (not received) since the last report |
total_KBytes_in | Number | Number of kilobytes (KB) received since the beginning of the call |
total_frames_decoded_in | Number | Total of frames decoded |
total_glitch_in | JSON | Number of freezes and pauses encountered since the beginning of the call |
total_nack_sent_in | Number | Total nack sent since the beginning of the call |
total_packets_lost_in | Number | Number of packets lost (not received) since the beginning of the call |
total_packets_in | Number | Number of packets received since the beginning of the call |
total_pli_sent_in | Number | Total pli sent since the beginning of the call |
total_time_decoded_in | Number | Total time used for decoding all frames (in ms) |
total_time_processing_delay_in | Number | Total time used for processing all frames (in ms) |
total_time_assembly_delay_in | Number | Total time used for assembling all frames (in ms) |
total_time_jitter_buffer_delay_in | Number | Total time spent by all frames in jitter buffer (in ms) |
total_jitter_emitted_in | Number | Total number of frames that have come out the jitter buffer (in ms) |
timestamp_out | Number | Timestamp when report has been received. Associated with delta_jitter_ms_out and delta_rtt_ms_out |
track_in | String | The id of the mediastream track associated |
Each outbound video stream contains the following statistics
Name | Value | Description |
---|
active_out | Boolean | True if that stream is active (sending media) |
codec_out | JSON | Description of the video output codec and parameters used |
codec_id_out | String | ID of the video output codec used |
delta_packet_delay_ms_out | Number | Average duration spent by packets before being sent (in ms) |
delta_KBytes_out | Number | Number of kilobytes (KB) sent since last report |
delta_kbs_out | Number | Number of kbits sent per second since the last report |
delta_jitter_ms_out | Number | Outgoing Jitter (in ms). Could be null when no value collected. |
delta_packets_lost_out | Number | Number of packets lost (not received by the recipient) since last report |
delta_encode_frame_ms_out | Number | Time needed to encode a frame |
delta_nack_received_out | Number | Nack received since the last report |
delta_pli_received_out | Number | Pli received since the last report |
delta_rtt_ms_out | Number | Round Trip-Time (in ms). Could be null when no value collected. |
encoder_out | String | Description of the video encoder used |
size_out | Object | Size of the output video sent + framerate (could be lower than the size asked) |
size_pref_out | Object | Size of the output video asked + framerate |
percent_packets_lost_out | Number | Percent of audio packet lost (not received by the recipient) since the last report |
limitation_out | Object | Object containing the reason and the durations spent in each state |
total_KBytes_out | Number | Number of kilobytes (KB) sent since the beginning of the call |
total_time_packets_delay_out | Number | Total time spent for all packets before being sent (in ms) |
total_packets_lost_out | Number | Number of packets lost (not received by the recipient) since the beginning of the call |
total_frames_encoded_out | Number | Total of frames encoded |
total_nack_received_out | Number | Total nack received since the beginning of the call |
total_pli_received_out | Number | Total pli received since the beginning of the call |
total_rtt_measure_out | Number | Number of RTT measurements done |
total_rtt_ms_out | Number | Total Round Trip Time since the beginning of the call |
total_time_encoded_out | Number | Total time used for encoding all frames |
timestamp_out | Number | Timestamp when report has been received. Associated with delta_jitter_ms_out and delta_rtt_ms_out |
track_out | String | The id of the mediastream track associated |
device_out | String | The label of the device associated to the track_out |
Network properties
Name | Value | Description |
---|
infrastructure | Number | Infrastructure level (0: Eth, 3: Wifi, 5: 4G, 10: 3G). (Deprecated) |
local_candidate_id | String | ID of the local candidate used |
local_candidate_protocol | String | Protocol used (udp, tcp) |
local_candidate_relay_protocol | String | Protocol used when relayed with TURN (udp, tcp, tls) |
local_candidate_type | String | Type of candidate used (host, relay, srflx) |
remote_candidate_id | String | ID of the remote candidate used |
remote_candidate_protocol | String | Protocol used (udp, tcp) |
remote_candidate_type | String | Type of candidate used (host, relay, srflx) |
Data properties
These stats are collected from the candidate-pair stats.
Name | Value | Description |
---|
delta_KBytes_in | Number | Number of kilobytes (KB) received since the last report (audio+video) |
delta_KBytes_out | Number | Number of kilobytes (KB) sent since last report (audio+video) |
delta_kbs_bandwidth_in | Number | Available incoming bitrate in kb/s (audio+video) |
delta_kbs_bandwidth_out | Number | Available outgoing bitrate in kb/s for (audio+video) |
delta_kbs_in | Number | Number of kbits received per second since the last report (audio+video) |
delta_kbs_out | Number | Number of kbits sent per second since the last report (audio+video) |
delta_rtt_connectivity_ms | Number | Round Trip-Time (in ms) computed from STUN connectivity checks |
total_KBytes_in | Number | Number of kilobytes (KB) received since the beginning of the call (audio+video) |
total_KBytes_out | Number | Number of kilobytes (KB) sent since the beginning of the call (audio+video) |
total_rtt_connectivity_measure | Number | Number of RTT measurements done (from STUN connectivity checks) |
total_rtt_connectivity_ms | Number | Total Round Trip Time since the beginning of the call (from STUN connectivity checks) |
Experimental
These stats are subject to change in the future
Name | Value | Description |
---|
time_to_measure_ms | Number | Time (ms) to measure a probe which means the time to collect and the time to compute the stats |
Stop reporting
At any time, calling the method stop()
stops collecting statistics on that probe. No other reports are received.
Generating a ticket
When calling the method stop()
or automatically after a duration equals to stopAfter
, a ticket is generated with the
most important information collected. This ticket is generated only if the option ticket
has not been manually set
to false
.
To obtain that ticket, subscribe to the event onticket
. The callback is fired when the probe is stopped (ie: by
calling the method stop()
) or after the stopAfter
. The callback is called with a JSON parameter corresponding to
something like a CDR.
If the option record
has been set to true
, the ticket contains all the reports generated.
The ticket generated contains the following information:
Name | Value | Description |
---|
call | Object | Contains the call_id and the events related to the call |
configuration | Object | Contains some configuration parameters such as the frequency |
data | Object | Contains the global statistics of the call |
details | Object | Contains the list of reports as well as the reference report |
ended | Date | End date of the ticket |
ssrc | Object | Contains the list of all statistics for all streams |
started | Date | Start date of the ticket |
ua | Object | Contains the ua , the pname and the user_id |
version | String | The version of the ticket format |
Each SSRC is an object containing the following statistics:
Name | Value | Description |
---|
direction | String | The direction of the stream. Can be inbound or outbound |
type | String | The type of the stream. Can be audio or video |
bitrate | Object | min , max , avg , values and volatility for Bitrate |
jitter | Object | min , max , avg , values and volatility for Jitter |
loss | Object | total , min , max , avg , values and volatility for Packets Loss |
rtt | Object | (Outbound only) min , max , avg , values and volatility for Round Trip Time |
mos | Object | (Audio only) min , max , avg , values and volatility |
traffic | Object | min , max , avg , values and volatility for Traffic |
limitations | Object | (Video outbound only) bandwidth , cpu , other , none for Limitations (in percent) |
PassThrough
WebRTCMetrics allows to capture any properties from the underlying reports generated by the WebRTC stack (aka
getStats API).
Basic usage
For doing that, you need to know which report the property belongs to, and use the key passthrough
to give it to *
WebRTCMetrics*.
Here is an example for capturing the audio level for any incoming streams as well as for the local source used
probe1 = metrics.createProbe(pc1, {
pname: 'pc-bob-1',
cid: 'call007984',
uid: 'Bob',
passthrough: {
"inbound-rtp": ["audioLevel"],
"media-source": ["audioLevel"]
}
});
The result will be added to each report in the following way:
{
"passthrough": {
"audioLevel": {
"inbound-rtp_audio=3691646660": 0.09140293588061159,
"media-source_audio=4252341231": 0.02352323323412
}
}
}
Advanced usage (units)
Starting version v5.4 you use some tags for collecting the property directly using the right unit.
For that, you can use tag ms
for using milliseconds and kbits
instead of having bytes.
probe1 = metrics.createProbe(pc1, {
pname: 'pc-bob-1',
cid: 'call007984',
uid: 'Bob',
passthrough: {
"inbound-rtp": ["bytesReceived.kbits"],
"remote-inbound": ["jitter.ms"]
}
});
Some metrics are cumulative, if you want to have a value per second, you can use the tag ps
.
probe1 = metrics.createProbe(pc1, {
pname: 'pc-bob-1',
cid: 'call007984',
uid: 'Bob',
passthrough: {
"inbound-rtp": ["ps:bytesReceived.kbits"],
"remote-inbound": ["jitter.ms"]
}
});
Advanced usage (computation)
Starting version 5.4, you can do computation with the properties collected
For that, you have to specify the properties to used and the operand.
probe1 = metrics.createProbe(pc1, {
pname: 'pc-bob-1',
cid: 'call007984',
uid: 'Bob',
passthrough: {
"remote-inbound-rtp": [
"[totalRoundTripTime/roundTripTimeMeasurements]"
],
"inbound-rtp": [
"[framesDecoded-keyFramesDecoded]",
"[totalDecodeTime/framesDecoded]",
"[pauseCount+freezeCount]",
"[totalFreezesDuration+totalPausesDuration]"
]
}
});
The following operands are supported: /
, +
, -
, *
. But only one kind of operand can be used in a formula.
You can have more than 2 properties in a formula.
Additional information
Callbacks
Setting the onreport
, onticket
and onresult
to null
, unregisters the callback previously registered.
Probes
You can get the list of available probes by using the probes
accessor.
import WebRTCMetrics from "webrtcmetrics";
const metrics = new WebRTCMetrics();
metrics.createProbe(firstPeerConnection);
metrics.createProbe(secondPeerConnection);
const probes = metrics.probes;
Probes can be started and stopped all together.
import WebRTCMetrics from "webrtcmetrics";
const metrics = new WebRTCMetrics();
metrics.createProbe(firstPeerConnection);
metrics.createProbe(secondPeerConnection);
metrics.startAllProbes();
metrics.stopAllProbes();
Events and custom events
Each probe records some WebRTC events related to the RTCPeerConnection
or to the devices used. These events are
collected and available in the ticket report.
Additionally, to these events, custom events can be recorded too.
import WebRTCMetrics from "webrtcmetrics";
const metrics = new WebRTCMetrics();
const probe = metrics.createProbe(firstPeerConnection);
const ssrc = null;
const data = { custom: "data" };
probe.addCustomEvent('an event', 'a category', 'a description of the event', new Date(), ssrc, { custom: "data" });
probe.addCustomEvent('an event', 'a category', 'a description of the event', new Date(), ssrc, { custom: "data" }, new Date());
Setting the logs level
Logs level can be set in two different ways:
import WebRTCMetrics from "webrtcmetrics";
const metrics = new WebRTCMetrics();
metrics.setupLogLevel('SILENT');