Pre-roll / mid-roll / post-roll
Pre-roll, mid-roll and post-roll are video ads named by when they play: a pre-roll runs before the content starts, a mid-roll interrupts it partway through, and a post-roll plays after it ends. Each position trades viewer patience against attention. Pre-rolls reach the most people, while post-rolls are often watched by fewer viewers.
Why it matters
Ad position shapes both revenue and retention. Pre-rolls earn on every start but can make viewers leave before the video begins. Mid-rolls catch engaged viewers but interrupt the story. Getting placement wrong costs either ad income or audience.
How it works
- The publisher decides break positions: before, during or after the content.
- Mid-roll positions are set by time or at natural pauses, such as scene changes.
- The player or server requests ads for each break, often through VAST and VMAP.
- Ads play at each position, and the viewer returns to the content afterward.
Which is better: pre-roll or mid-roll ads?
Pre-roll ads reach the most viewers, while mid-roll ads often hold more attention because viewers are already invested. Pre-rolls risk viewers leaving before the video starts. Mid-rolls suit longer content, where a break at a natural pause feels less intrusive. Many services combine both.
How long should a pre-roll ad be?
A pre-roll ad is often 6 to 30 seconds, with shorter lengths working better for short content. For example, YouTube lets viewers skip skippable ads after 5 seconds, caps non-skippable ads at 15 seconds in most markets and limits bumper ads to 6 seconds.
Where it's used
OTT services place mid-rolls at natural scene breaks in long shows. Microdrama apps run short ads between episodes, and creator platforms balance pre-rolls against viewers leaving early.
By the numbers
- Google Ads says viewers can skip skippable in-stream ads after the first 5 seconds, and non-skippable in-stream ads can be up to 15 seconds in most markets. (How video ads work (Google Ads Help))
- Google Ads limits bumper ads to a maximum of 6 seconds. (How video ads work (Google Ads Help))
