Non-skippable in-stream ads
What are in-stream ads?
Non-skippable in-stream ads are video ads that may appear pre-, mid-, or post-roll while viewing partner content. They can be up to 15-20 seconds long and viewers must watch the ad before they're able to watch the selected video. A companion 300x60-pixel ad unit may be usually displayed alongside YouTube videos that show in-stream ads on desktop.
In-stream ads are sold on a CPM basis, and may generate higher CPMs than other ad formats on YouTube. Please note that while non-skippable in-stream ads may generate higher revenue than other ad formats, they also have a higher abandonment rate. Enabling this ad format across your videos can lead to lower video views and watch time. It's up to you to determine the best balance between views/watch time and revenue for your channel, and you can use the Ad Performance and Views reports in YouTube Analytics to help you make that decision.
When do in-stream ads appear?
A host of dynamic signals, including content type and how a user discovered the video, help determine the best time to serve an in-stream ad. When we don't have inventory to display in-stream ads against your videos, we'll backfill with other ad formats.
How are non-skippable in-stream ads different than TrueView in-stream ads?
If a non-skippable in-stream ad appears before a video, the viewer must watch the ad in full before the video will play. With TrueView in-stream ads, viewers have the option watch the ad in full or to skip the ad after viewing it for 5 seconds. Both in-stream ad formats may generate higher CPMs than other ad formats on YouTube, but non-skippable in-stream ads have higher video abandonment rates than skippable TrueView in-stream ads.