OpenTok Network Test

This Node module lets you check network connectivity to resources and services required to use OpenTok. Run this on a web client to get the following information:

• Whether the client will be able to succeed in connecting to an OpenTok session

• MOS estimates for the audio and video quality the client will experience

• A recommended frame rate and resolution to use for publishing to a session

For a sample that uses this module, see the OpenTok Pre-call Test tool.

Example Usage in Node/Browserify/Webpack

First, install the package:

$ npm install opentok-network-test-js

Now load the OpenTok Network Test in your project. The module exports two objects:

• NetworkTest -- The class containing methods for testing your OpenTok connectivity and quality. This is the default export.

• ErrorNames -- An object enumerating error name values

Using CommonJS:

const NetworkTest = require('opentok-network-test-js').default;
const ErrorNames = require('opentok-network-test-js').ErrorNames;

... or ES6 ...

import NetworkTest, { ErrorNames } from 'opentok-network-test-js';

Load the OpenTok.js library.

Instantiate an instance of the test object, passing in the OpenTok.js OT object and a configuration object. The configuration object contains an API key for your app's OpenTok project, a session ID for a test session, and a token for that session:

const otNetworkTest = new NetworkTest(OT, {
  apiKey: '123456', // Add the API key for your OpenTok project here.
  sessionId: '1_MX40NzIwMzJ-fjE1MDElGQkJJfn4', // Add a test session ID for that project
  token: 'T1==cGFydG5lcXN0PQ==' // Add a token for that session here
});

Use the OpenTok server SDKs to generate a unique session ID for each client. This session ID is used for the network test, and it must be different than the session ID used for communication in the app. The test session must be a routed session -- one that uses the OpenTok Media Router. Also generate a test token that has publish privileges.

Then run the test methods:

otNetworkTest.testConnectivity().then((results) => {
  console.log('OpenTok connectivity test results', results);
  otNetworkTest.testQuality(function updateCallback(stats) {
    console.log('intermediate testQuality stats', stats);
  }).then((results) => {
    // This function is called when the quality test is completed.
    console.log('OpenTok quality results', results);
    let publisherSettings = {};
    if (results.video.reason) {
      console.log('Video not supported:', results.video.reason);
      publisherSettings.videoSource = null; // audio-only
    } else {
      publisherSettings.frameRate = results.video.recommendedFrameRate;
      publisherSettings.resolution = results.video.recommendedResolution;
    }
    if (!results.audio.supported) {
      console.log('Audio not supported:', results.audio.reason);
      publisherSettings.audioSource = null;
      // video-only, but you probably don't want this -- notify the user?
    }
    if (!publisherSettings.videoSource && !publisherSettings.audioSource) {
      // Do not publish. Notify the user.
    } else {
      // Publish to the "real" session, using the publisherSettings object.
    }
  }).catch((error) => {
    console.log('OpenTok quality test error', error);
  });
}).catch(function(error) {
  console.log('OpenTok connectivity test error', error);
});

You can also run the tests in audio-only mode by passing in an options object with audioOnly set to true into the constructor:

const sessionInfo = {
  apiKey: '123456', // Add the API key for your OpenTok project here.
  sessionId: '1_MX40NzIwMzJ-fjE1MDElGQkJJfn4', // Add a test session ID for that project
  token: 'T1==cGFydG5lcXN0PQ==' // Add a token for that session here
}
const options = {audioOnly: true};
const otNetworkTest = new NetworkTest(OT, sessionInfo, options);
 
otNetworkTest.testQuality(function updateCallback(stats) {
  const currentStats = stats[stats.length - 1];
  console.log('testQuality stats', currentStats);
}).then((results) => {
  console.log('OpenTok quality results', results);
}).catch((error) => {
  console.log('OpenTok quality test error', error);
});

This code uses Promises returned by the OTNetworkTest.testConnectivity() and OTNetworkTest.testQuality() methods. Alternatively, you can pass completion handler functions into each of these methods.

See the following section for details on using the test results.

See the /sample subdirectory (and the /sample/README.md file) for a sample app.

Supported browsers

The OTNetworkTest.testConnectivity() method is supported in Chrome, Firefox, Safari, Internet Explorer, Opera, and Edge.

The OTNetworkTest.testQuality() method is supported in Chrome, Firefox, Safari, Opera, Chromium-based versions of Edge (versions 79+), and Internet Explorer. It is not supported in non-Chromium-based versions of Edge.

API reference

The OTNetworkTest NPM module includes three public methods:

• The OTNetworkTest() constructor method

• The OTNetworkTest.testConnectivity() method

• The OTNetworkTest.testQuality() method

Note: Some API changes were introduced in v2. See the releases page for details.

OTNetworkTest() constructor

The OTNetworkTest() constructor includes the following parameters:

• ot -- A reference to the OpenTok.js OT object. You must load OpenTok.js into the web page and pass the OpenTok.js OT into the OTNetworkTest() constructor.

  Note that you may load OpenTok.js from the opentok.com server (https://static.opentok.com/v2/js/opentok.js) or via NPM (https://www.npmjs.com/package/@opentok/client). Or if your OpenTok project uses the enterprise environment, you will load OpenTok.js from the enterprise URL.

  Passing the OT object into the OTNetworkTest() constructor ensures that the tests will use the same version of OpenTok and the same OpenTok environment that will be used by the main OpenTok session in your application.

• sessionInfo -- An object containing the following:

  • apiKey -- The API key corresponding to the OpenTok project the app uses.

  • sessionId -- A test session ID. This must be an ID for a different session than the one that your application will be used for communication. Generate a unique session ID for each client. This session ID is used for the network test, and it must be different than the session ID used for communication in the app. The test session must be a routed session -- one that uses the OpenTok Media Router.

    To test connectivity in a specific region, specify a location hint when creating the test session.

  • token -- A token corresponding to the test session. The role of the token must be either publisher or moderator.

    The sessionInfo parameter is required.

• options --The options parameter is an object containing the following properties, both of which are optional:

  • audioOnly (Boolean) -- Set this property to true to run audio-only tests.

  When this option is set to false (the default), the quality test will try to run an audio-video quality test (using both the camera and microphone). If there is no camera available, or if the results of the audio-video test do not support adequate audio quality, the test continues in audio-only mode.

  Setting the audioOnly to true will reduce the time of the quality test on systems that have both a microphone and camera attached (since the audio-only test is shorter than the audio-video test).

  • timeout (Number) -- Set this property to the maximum duration of the testQuality() test, in milliseconds. Set this to a value greater than 5000 (5 seconds) but less than 30000 (30 seconds). (Values outside of this range are ignored.) If you do not set this value, the testQuality() test will run for approximately 30 seconds for an audio-video test or for 10 seconds for an audio-only test.

    The timeout period begins when the quality test starts publishing (after the user grants access to the camera and microphone).

    Setting a lower timeout duration may result in less accurate results, including MOS ratings.

  The options parameter is optional.

The constructor throws an Error object with a message property and a name property. The message property describes the error. You should check the name property to determine the type of error. The name property will be set to one of the values defined as properties of the ErrorNames object (see ErrorNames). For example:

try {
  const otNetworkTest = new NetworkTest(OT, sessionInfo);
} catch (error) {
  switch (error.name) {
    case ErrorNames.MISSING_OPENTOK_INSTANCE:
      console.error('Missing OT instance in constructor.');
      break;
    case ErrorNames.INCOMPLETE_SESSON_CREDENTIALS:
    case ErrorNames.MISSING_SESSON_CREDENTIALS:
    case ErrorNames.INVALID_SESSON_CREDENTIALS:
      console.error('Missing or invalid OpenTok session credentials.');
      break;
    default:
      console.error('Unknown error .');
  }
}

OTNetworkTest.testConnectivity()

This method checks to see if the client can connect to OpenTok servers. The method returns a Promise that is resolved when the connectivity check completes. The promise is resolved with a results object that has the following two properties:

• success (Boolean) -- true if connectivity to OpenTok servers succeeded; false if any connectivity test failed.

• failedTests (Array) -- If connectivity failed, this array contains an object for each failure type. The object has two properties, type and errors:

  • type -- A sting defining the failure type. It will be set to one of the following values:

    • 'api' -- The test could not connect to the OpenTok API server. Connection to this server is required to connect to an OpenTok session.

    • 'messaging' -- The test could not establish a connection to the OpenTok messaging WebSocket. This connection is required to connect to an OpenTok session. In addition to other causes for WebSocket connectivity failures, this failure type will occur if you pass an invalid OpenTok API key, session ID, or token into the OTNetworkTest() constructor.

    • 'media' -- The test could not connect to the OpenTok Media Router. If your app uses a routed session, it will not succeed in using OpenTok. However, if your app uses a relayed session, the client may still succeed in using the OpenTok session, although it may fail if the relayed session requires use of a TURN server.

    • 'logging' -- The test could not connect to the OpenTok logging server. The OpenTok.js library periodically logs data (such as video and audio quality) to this server. The client can still connect to an OpenTok session, however TokBox will not collect data that may help you debug issues with the session, using tools like OpenTok Inspector.

  • error -- An object defining the reason for the type of failure. This object includes a message property and a name property. The message property describes the error. You should check the name property to determine the type of error. The name property will be set to one of the values defined as properties of the ErrorNames object (see ErrorNames):

    For example:

    otNetworkTest.testConnectivity(function(results) {
      results.failedTests && results.failedTests.forEach(result) => {
        switch (failedTest.error.name) {
          case ErrorNames.FAILED_TO_OBTAIN_MEDIA_DEVICES:
          // Display UI message about granting access to the microphone and camera
            break;
          case ErrorNames.NO_AUDIO_CAPTURE_DEVICES:
          case ErrorNames.NO_VIDEO_CAPTURE_DEVICES:
            // Display UI message about no available camera or microphone
            break;
          // Handle other errors, as needed
          default:
            console.error('Unknown error .');
        }
      }
    });

  If all connectivity tests succeed, the failedTests property is undefined.

OTNetworkTest.testQuality(updateCallback)

This function runs a test publisher (using the API key, session ID and token provided in the constructor). Based on the measured video bitrate, audio bitrate, and the audio packet loss for the published stream, it provides the following results:

• Whether audio and video are supported and a reason why they aren't supported (if they aren't).

• The MOS estimate (from 0 - 5) for the the audio and video published by the client.

• Statistics for the test, including bitrate and packet loss ratio (for both audio and video), as well as the video packet loss ratio.

• The recommended supported publisher settings. These settings include the recommended video frame rate and resolution for a stream published by the client. Or, if the stats do not support video, the results indicate whether an audio-only published is recommended or not, based on the measured audio bitrate and packet loss.

This method takes one parameter: updateCallback. The method returns a Promise.

updateCallback

The updateCallback function is called periodically during the test (at a 1-second test interval).

The object passed into the updateCallback function includes statistics about the audio and video in the test stream. The object has the following data:

{
  audio: {
    timestamp: 1509747314,
    bytesReceived: 434349, // The total number of audio bytes received, cumulative
    packetsReceived: 24234,  // The total number of audio packets received, cumulative
    packetsLost: 0   // The total number of audio packets lost, cumulative
  },
  video: {
    timestamp: 1509747314,
    bytesReceived: 434349, // The total number of video bytes received, cumulative
    frameRate: 15,   // The video frame rate
    packetsReceived: 24234,  // The total number of video packets received, cumulative
    packetsLost: 0   // The total number of video packets lost, cumulative
  },
  timestamp: 1512679143897, // The timestamp of the sample
  phase: 'audio-video' // Either 'audio-video' or 'audio-only'
}

The phase property is set to 'audio-video' during the initial audio-video test. If a secondary audio-only test is required (because audio quality was not acceptable during the audio-video test), the property is set to 'audio-only'.

Pass in a null value if you do not want to register an updateCallback function.

Promise returned

The Promise returned by the OTNetworkTest.testQuality() method is resolved when the connectivity check completes. The promise is resolved with a results object that has the following properties:

• video (Object) -- Contains the following properties:

  • supported (Boolean) -- Whether the results indicate that video is supported.

  • recommendedFrameRate (Number) -- The recommended video frame rate. However, if video is unsupported, this is set to null. If the the test ran in audio-only mode (for example, because no camera was found), this property is undefined.

  • recommendedResolution (String) -- The recommended video resolution. This will be set to '1280x720', '640x480', or '320x240'. However, if video is unsupported, this is set to null. If the the test ran in audio-only mode (for example, because no camera was found), this property is undefined.

  • reason (String) -- A string describing the reason for an unsupported video recommendation. For example, 'No camera was found.'

  • bitrate (Number) -- The average number of video bits per second during the last five seconds of the test. If the the test ran in audio-only mode (for example, because no camera was found), this property is undefined.

  • frameRate (Number) -- The average number of frames per second during the last five seconds of the test. Note that this is different than the recommendedFrameRate. The frameRate value is the actual frame rate observed during the test, and the recommendedFrameRate is the recommended frame rate. If the the test ran in audio-only mode (for example, because no camera was found), this property is undefined.

  • packetLossRatio (Number) -- The audio packet loss ratio during the last five seconds of the test. If the the test ran in audio-only mode (for example, because no camera was found), this property is undefined.

  • mos (Number) -- The MOS estimate for the test video quality. This will be in a range from 1 to 4.5. See MOS estimates below for more information.

• audio (Object) -- Contains the following properties:

  • supported (Boolean) -- Whether audio will be supported (true) or not (false).

  • reason (String) -- A string describing the reason for an unsupported audio recommendation. For example, 'No microphone was found.'

  • bitrate (Number) -- The average number of audio bits per second during the last five seconds of the test.

  • packetLossRatio (Number) -- The video packet loss ratio during the last five seconds of the test.

  • mos (Number) -- The MOS estimate for the test audio quality. This will be in a range from 1 to 4.5. See MOS estimates below for more information.

results is undefined if there was an error in running the tests (and the error parameter is unset).

Important: v1 included a results.mos property (an overall MOS rating for the test). This was removed in v2 and replaced with results.audio.mos and results.video.mos properties.

The results, including the MOS estimates and the recommended video resolution and frame rate are subjective. You can adjust the values used in the source code, or you can use the data passed into the updateCallback() function and apply your own quality analysis algorithm.

The Promise returned by the OTNetworkTest.testQuality() method is rejected when the connectivity check encounters an error. The promise is reject with an error object that has two properties: a message property and a name property. The message property describes the error. You should check the name property to determine the type of error. The name property will be set to one of the values defined as properties of the ErrorNames object (see Error.name values).

otNetworkTest.testQuality(null, function updateCallback() {
  // process intermediate results
}).then((results) => {
  // Display UI based on results
}).catch((error) => {
    switch (error.name) {
      case ErrorNames.UNSUPPORTED_BROWSER:
        // Display UI message about unsupported browser
        break;
      case ErrorNames.CONNECT_TO_SESSION_NETWORK_ERROR:
        // Display UI message about network error
        break;
      case ErrorNames.FAILED_TO_OBTAIN_MEDIA_DEVICES:
        // Display UI message about granting access to the microphone and camera
        break;
      case ErrorNames.NO_AUDIO_CAPTURE_DEVICES:
      case ErrorNames.NO_VIDEO_CAPTURE_DEVICES:
        // Display UI message about no available camera or microphone
        break;
      default:
        console.error('Unknown error .');
    }
});

OTNetworkTest.stop()

Stops the testConnectivity() test if it is running. The test will not stop until it has been running for at least 5 seconds (after the user has granted access to the camera and microphone). While you can call stop() prior to this, results will not be returned until the 5-second mark.

ErrorNames

The ErrorNames object includes properties that enumerate values used in the name property of OTNetworkTest error objects. You should check the name property of an error object (against the values defined in ErrorNames) to determine the type of error.

Errors thrown by the OTNetworkTest() constructor

testConnectivity() errors

The testConnectivity() returns a JavaScript promise that succeeds with a results object. The results object contains a failedTests array, and each element of this array (if there are any elements) has an error property, which is error object has a name property set to one of the following:

testQuality() errors

If the promised returned by the testQuality() is rejected, the error passed into the .catch() method has a name property set to one of the following:

MOS estimates

The testQuality() results include MOS estimates for video (if supported) and audio (if supported).

A MOS estimate is a rating of audio or video quality. In subjective scoring, a user is asked to rate quality from 1 (bad) to 5 (excellent). This module uses an objective test, calculating the MOS value based on bitrate, packet loss ratio, and (for video) resolution. For example, the audio MOS calculation is based on the ITU G.107 specification. These algorithms limit the range of scores from 1.0 to 4.5.

Building the module

To build the module:

$ npm install
$ npm run build

Sample app

See the /sample subdirectory (and the /sample/README.md file) for a sample app.