Track quality of experience using JavaScript 2.x

Last update: 2022-11-11
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The following instructions provide guidance for implementation across all 2.x SDKs.


If you are implementing a 1.x version of the SDK, you can download the 1.x Developers Guides here: Download SDKs.

Implemement QOS

  1. Identify when the bitrate changes during media playback and create the MediaObject instance using the QoS information.

    QoSObject variables:


    These variables are only required if you are planning to track QoS.

    Variable Description Required
    bitrate Current bitrate Yes
    startupTime Startup time Yes
    fps FPS value Yes
    droppedFrames Number of dropped frames Yes

    QoS object creation:

    // Replace <bitrate>, <startuptime>, <fps> and
    // <droppeFrames> with the current playback QoS values.
    var qosObject = MediaHeartbeat.createQoSObject(<bitrate>,
  2. When playback switches bitrates, call the BitrateChange event in the Media Heartbeat instance:

    _onBitrateChange = function() {
        this._mediaHeartbeat.trackEvent(MediaHeartbeat.Event.BitrateChange, qosObject);

    Update the QoS object and call the bitrate change event on every bitrate change. This provides the most accurate QoS data.

  3. Make sure that getQoSObject() method returns the most updated QoS information.

  4. When the media player encounters an error, and the error event is available to the player API, use trackError() to capture the error information. (See Overview.)


    Tracking media player errors will not stop the media tracking session. If the media player error prevents the playback from continuing, make sure that the media tracking session is closed by calling trackSessionEnd() after calling trackError().

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