DocumentationAnalyticsStreaming media services guide

Chapter position

Last update: June 8, 2026

CREATED FOR:

  • Developer

This page covers data collection for the Chapter position variable. See Chapter position for the corresponding reporting dimension.

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The chapter position variable is the index of the chapter inside the content, starting at 1 (typical) or 0 (depending on your convention). Use a stable index per chapter so that the same chapter rolls up across sessions.

Property
Value
Context data variable
a.media.chapter.position
XDM collection field
xdm.mediaCollection.chapterDetails.index
Audience Manager trait
c_contextdata.a.media.chapter.position
Required
No (Mobile SDK); Yes (Edge, Media Collection API)
Sent with
Chapter start, chapter close
Web SDK

Set index inside xdm.mediaCollection.chapterDetails when calling sendEvent:

code language-javascript 
alloy("sendEvent", {
  xdm: {
    eventType: "media.chapterStart",
    mediaCollection: {
      chapterDetails: {
        friendlyName: "Pilot Episode - Opening",
        index: 1,
        offset: 0,
        length: 240
      },
      sessionID: "{sid}",
      playhead: 0
    }
  }
});
iOS

Pass the chapter position as the second argument to createChapterObject.

code language-swift 
let chapterObject = Media.createChapterObjectWith(name: "Pilot Episode - Opening",
                                              position: 1,
                                                length: 240,
                                             startTime: 0)

tracker.trackEvent(event: MediaEvent.ChapterStart, info: chapterObject, metadata: nil)
Android

Pass the chapter position as the second argument to createChapterObject.

code language-kotlin 
val chapterObject = Media.createChapterObject("Pilot Episode - Opening",
                                              1L,
                                              240.0,
                                              0.0)

tracker.trackEvent(Media.Event.ChapterStart, chapterObject, null)
Roku Edge

Set index inside xdm.mediaCollection.chapterDetails when calling sendMediaEvent for media.chapterStart:

code language-brightscript 
m.aepSdk.sendMediaEvent({
    "xdm": {
        "eventType": "media.chapterStart",
        "mediaCollection": {
            "chapterDetails": {
                "friendlyName": "Pilot Episode - Opening",
                "index": 1,
                "offset": 0,
                "length": 240
            },
            "playhead": 0
        }
    }
})
Media Edge API

Call the chapterStart endpoint with index inside xdm.mediaCollection.chapterDetails:

code language-json 
{
  "events": [{
    "xdm": {
      "eventType": "media.chapterStart",
      "mediaCollection": {
        "chapterDetails": {
          "index": 1,
          "offset": 0,
          "length": 240
        },
        "sessionID": "{sid}",
        "playhead": 0
      }
    }
  }]
}

Legacy implementation types (Analytics-only)

Media SDK JS 3.x

Pass the chapter position as the second argument to ADB.Media.createChapterObject:

code language-javascript 
var chapterInfo = ADB.Media.createChapterObject(
  "Pilot Episode - Opening",
  1,
  240,
  0
);

tracker.trackEvent(ADB.Media.Event.ChapterStart, chapterInfo, contextData);
Chromecast

Pass the chapter position as the second argument to ADBMobile.media.createChapterObject:

code language-javascript 
var chapterInfo = ADBMobile.media.createChapterObject(
  "Pilot Episode - Opening",  // name
  1,                          // position
  240,                        // length
  0                           // startTime
);
ADBMobile.media.trackEvent(ADBMobile.media.Event.ChapterStart, chapterInfo, null);
Roku 2.x

Pass the chapter position as the second argument (position) to adb_media_init_chapterinfo:

code language-brightscript 
adb = ADBMobile()
chapterInfo = adb_media_init_chapterinfo("Pilot Episode - Opening", 1, 240.0, 0.0)  ' name, position, length, startTime

adb.mediaTrackEvent(adb.MEDIA_CHAPTER_START, chapterInfo)
Media Collection API

Include media.chapter.index in the params object of your chapterStart POST request:

code language-json 
{
  "playerTime": { "playhead": 0, "ts": 1699523820000 },
  "eventType": "chapterStart",
  "params": {
    "media.chapter.index": 1
  }
}

See the Media Collection API events reference for the full request structure.

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