For standard ad metadata, create a dictionary of standard ad metadata key value pairs using the keys for your platform:
var adObject =
ADB.Media.createAdObject(<AD_NAME>,
<AD_ID>,
<POSITION>,
<LENGTH>);
// Set standard Ad Metadata
var adMetadata = {};
adMetadata[MediaHeartbeat.AdMetadataKeys.Advertiser] = "Sample Advertiser";
adMetadata[MediaHeartbeat.AdMetadataKeys.CampaignId] = "Sample Campaign";
tracker.trackEvent(ADB.Media.Event.AdStart, adObject, adMetadata);