Merge pull request #80 from Financial-Times/analytics-docs

Documented the video analytics

analytics.md

@@ -0,0 +1,52 @@
+# Video analytics
+
+An overview of the o-video analytics.
+
+## Adverts events
+
+The advert events are fired by the [Google IMA SDK](https://developers.google.com/interactive-media-ads/docs/sdks/html5/v3/apis#ima.AdEvent.Type).
+
+- adStart - The advert started.
+- adComplete - The advert finished (i.e. played through to the end).
+- adSkippable - The advert is skippable, fired when the state changes to skippable.
+- adSkip - The user skipped the advert.
+
+Each event comes with extra detail.
+
+```js
+detail: {
+	advertising: true,
+	category: 'video',
+	contentId: this.video.opts.id,
+	progress: 0,
+	adDuration: ad.getDuration(),
+	adMinDuration: ad.getMinSuggestedDuration(),
+	adTitle: ad.getTitle(),
+	adProgress: this.getAdProgress()
+}
+```
+
+More details of the `ad.*` API calls are in the [IMA SDK](https://developers.google.com/interactive-media-ads/docs/sdks/html5/v3/apis).
+
+## Video events
+
+The video events are fired as part of the [native HTML Media Events API](https://developer.mozilla.org/en/docs/Web/Guide/Events/Media_events).
+
+- playing - The video started playing.
+- progress - The video played through to a particular waypoint, defaults to firing events at ~25/50/75/100% progress.
+- ended - The video played through to the end
+- seeked - The user jumped to a point in the video.
+- pause - The user paused the video.
+
+Each event has the following additional properties,
+
+```js
+detail: {
+	action: ev.type,
+	advertising: video.opts.advertising,
+	category: 'video',
+ 	contentId: video.opts.id,
+	progress: video.getProgress(),
+	duration: video.videoEl.duration
+}
+```