How do I calculate the render rate for a MediaTailor configuration?

Last updated: 2022-03-24

I want to calculate the render rate for my ad impressions in AWS Elemental MediaTailor. How do I use Amazon CloudWatch for this?

Short description

Amazon CloudWatch monitors metrics and logs from AWS Elemental MediaTailor. CloudWatch metrics provide a variety of reports, including MediaTailor billing. The metrics show a granular view or a per-configuration view of the total number of advertisements inserted. CloudWatch metrics also calculate the render rate. Render rate is the percentage of ad impressions served out of the total number of ads received back from the Ad Decision Server (ADS). MediaTailor calculates the render rate as (AdImpressions/AdsReturned)*100.

CloudWatch records AdImpressions as Avail.impression. The value increments when the first segment of an advertisement is requested. AdsInserted is recorded as AdDecisonServer.Ads. The value increments when MediaTailor inserts an advertisement in the manifest.


  1. Open the CloudWatch console.
  2. On the left-hand navigation bar, choose Metrics, All metrics.
  3. In the All metrics tab, in AWS namespaces, choose MediaTailor. This displays all metrics for the MediaTailor service.
  4. Under Metrics, choose Configuration Name. In the search bar, enter the name of the configuration that you want to calculate the render rate for.
  5. For the specific ConfigurationName, select the AdDecisionServer.Ads metric.
  6. In the same ConfigurationName, select the Avail.Impression metric.
  7. In the upper right corner of the graph, select the time period. Change the format of the graph from Line to Number.
  8. In the Graphed metrics, for the Statistic, choose Sum. This displays the total number of impressions as a number.
  9. Calculate the render rate for this configuration using the math percentage expression:
    In the Graphed metrics tab, select the arrow next to Math expression.
    Choose Common, Percentage. This creates a new row in the table with an Id.
    For the Label, enter Render Rate. Make a note of the IDs for AdDecisionServer.Ads and Avail.Impression.
    In Details, enter 100*(ID for Avail.Impression/ID for AdDecisionServer.Ads). For example, if m1 is the AdDecisionServer.Ads and m2 is the Avail.Impression, then enter 100*(m2/m1). Under the Untitled graph you see the Render Rate.
  10. To add a name to the metrics and the graph, select the pencil icon next to Untitled graph. Enter the name for the graph. To change the label of the Id, select the pencil icon next to the label.

Scenarios that might result in low impressions

Scenario 1

If the first request for an ad manifest has an ad break one minute before the live edge, then you might see a low impression count. By default, MediaTailor fills the ad break with ads. If the player starts playing at the live edge, the viewer doesn't see the ad that MediaTailor inserted. In this case, the best practice is to turn on avail suppression. See Configuring ad break suppression for details.

Scenario 2

When an ad break starts in a stream that a viewer is watching, if MediaTailor inserts multiple ads but the viewer closes the player during the first ad, MediaTailor doesn't send impressions for the remaining unwatched ads.

There might be additional scenarios that result in lower than expected impressions. For more information, see Monitoring and tagging in the AWS Elemental MediaTailor User Guide.

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