These events are fired whenever there is a video impression (a video is loaded but not necessarily played) or played (whether by the user initiating playback or autoplay).
Viewing your analytics
What do we track?
- Whenever the play button is pressed, to begin video playback.
- When an autoplaying video begins playback.
The vzaar Playability Index
|Video||Impressions||Plays||% Plays to Impressions|
“Here p̂ is the observed fraction of plays, zα/2 is the (1-α/2) quantile of the standard normal distribution, and n is the total number of impressions.” - source: Evan Miller, Feb. 2009 (adapted for context)
Downloading your analytics
- Because, when we deliver a video to your viewer, we don't just deliver the video data itself. We have to also deliver the video player and the poster frame (so that we have something to show your viewer before playback begins). Those assets are relatively small (e.g. the player is ~200K) but it does multiply and it is a factor
- Because of browser preloading. Even just loading the player preloads a small amount of video data. There is an HTML attribute we can use to tell the browser how much data to download. You can read the background in this article: HTML5 Video Preload I don't expect you to read the whole thing so here's the important part. We use the `preload='metadata'` attribute value to tell the browser to not pre-load any video itself, just the metadata (dimensions, first frame, duration, and so on).
You'll see from that article that many modern browsers (including the most popular browsers Chrome and IE, ignore the value and download video data anyway. We have absolutely no control over this behavior. You'll further see form that article that the amount of video preloaded varies across the major desktop browsers and browsers tend to preload too much by default.
- Because of CDN propagation. Propagation is when we send your video out to caching servers in our CDN so that, when your viewers go to play them, the videos will load much faster regardless of where they are in the world. Again, like the player itself and the poster frame, CDN propagation tends to account for a (relatively) small amount of bandwidth but, when multiplied across many videos, it is a factor. It's also, because of it's nature, more of a factor early on as propagation happens when you initially upload your videos.of
deleted - We keep data on your videos even after they are deleted so they are included in the report. You may care to simply sort the sheet data by that column and delete all rows with "Deleted" in the `deleted` column.
CFRs - these are "CDN file requests". Simply put, we used to measure a play anytime there was a request to the CDN for the underlying video file. But, we found that many modern mobile clients might make multiple requests for the same video file for a single user during a single view. For that reason, we recently completely re-engineered our approach to gathering analytics to produce numbers which more accurately mapped on to end-user viewer behavior. It's a complex and subtle issue and you can read more background here: Dev Chat: The Next Generation Of Video Analytics
As stated above, impressions and plays are only captured when our player is embedded using the vzaar iframe. The last three options here allow you to see video activity which occurs outside the iframe:
Include Download Counts: counts video downloads initiated via the
/download URL download or via the in-player, social sharing button.
Include Non-iframe Embed Video Requests: counts videos accessed via the
/video URL. This would be typical if you're using a third-party player or you're playing back video on a mobile device using native media classes.
Include Podcast Play Counts: counts plays which result from use of the vzaar Podcast feature.