Pre-roll, Mid-Roll, Post-Roll Ads : Definitions and Usage in Video Monetization

Ads inserted into videos are classified into Pre-Roll, Mid-Roll, Post-Roll ads based on their position or placement in the video i.e., before, in the middle, or after the video completes playback.

In this article, we take a look at these ad types and some common recommendations and gotchas while dealing with them. By the way, if you are new the ad-tech, do check out OTTVerse’s comprehensive guides to

  1. AVOD or Advertising-Based Ad insertion
  2. Difference between AVOD, SVOD, PVOD, TVOD
  3. Client-Side Ad Insertion & Server-Side Ad Insertion
  4. Introduction to VAST
  5. Introduction to VPAID
  6. An Introduction to Fill-Rate Calculations

With that short introduction to ad positions, let’s dive right into the concepts of pre, mid, and post-roll ads and learn more about them.

What is a Pre-Roll Ad?

A pre-roll ad is an ad that is played before the video starts to play – which is why it has the word “pre” in its name. When you click on a video that you want to watch, and if that video has a pre-roll ad associated with it, then the player will first play the pre-roll ad and then begin to display the video that you requested.

pre-roll ad placement

Pre-roll ads are a great way of monetizing VOD content and commonly used by AVOD services. There are a few distinct advantages to using pre-roll ads.

  • The user has explicitly requested the video and is interested in watching it. So, the likelihood of the user watching the ad is quite high, and his chances of abandoning the video simply because it contains an ad is low.
  • Ad fatigue probably hasn’t set in, and an AVOD service provider can get away with a couple of pre-roll ads right at the start of the video – especially if the video is popular and in-demand.

However, you should take care not to annoy the user with pre-roll ads –

  • Do ensure that you don’t stuff 4-5 ads right at the start of the movie. It’s plain annoying!
  • Make sure that your ad-delivery infrastructure is top-notch. Absolutely no user will be tolerant of buffering, crashes, freezes, or start-up delays in ad delivery.
  • If you have an auto-playlist, be aware that the user might be subjected to a video post-roll ad and immediately, the next video’s pre-roll ad. That’s two sets of ads back-to-back and it can be annoying. It might be a good idea to avoid such ad-placement for auto-playlists.
pre roll ad
Pre-roll ad in YouTube

What is a Mid-Roll Ad?

Mid-roll ads are those ads that are played by interrupting the video playback. The video is paused, the mid-roll ad is played, and after the mid-roll ad is completed or skipped, the video playback is resumed.

mid-roll ad placement

All of us have experienced mid-roll ads while watching videos on YouTube or on AVOD-based streaming services. There are several points to be taken into consideration for mid-roll ads –

  1. Placement – where do you place the mid-roll ads and how far apart? If you place several mid-roll ads close to each other, then the user is bound to get annoyed.
  2. Frequency – how many mid-roll ads are you going to insert into the video? If your video is 10 mins long and you insert two 30-second ads every one minute, then your user is probably going to flee! On the other hand, if you insert only two ads in a 10 min long video, is that going to help or hurt your bottom-line? There is a fine line between making income and annoying your users 😉
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However, mid-roll ads are considered to be high-converting ad units with pretty high completion rates. I guess that comes down to the fact that users might watch or skip over your ad unit while watching a movie, but, they are unlikely to abandon the movie simply because of an ad.

What is a Post-Roll Ad?

Post-roll ad position refers to ads that are played after the video is completed and before the next video playback starts.

post-roll ad placement

One thing to note is that if your videos are on autoplay and you see an ad after the video completes, it could be the post-roll ad of the video you just completed watching, or it could be the pre-roll ad of the next video in the playlist.

This confusion can be cleared up by looking at the VAST response of the ad which should clearly state that the ad is either a pre-roll or a post-roll ad.

Post-roll ads have a poor record in terms of completion rates because there is no incentive for the user to watch them. The user has completed watching the video and will typically move on to another video, thereby skipping the post-roll ad.

post-roll ad 
mid-roll ad
pre-roll ad


That’s it folks – I hope you understood the difference between pre-roll, mid-roll, and post-roll ads in video ad insertion and were able to get an appreciation of the use of each of these ad-placements.

Until next time, stay safe and keep streaming. If you are interested in learning more about Ad-Tech, then check out these articles.

krishna rao vijayanagar
Krishna Rao Vijayanagar

Krishna Rao Vijayanagar, Ph.D. is the Editor-in-Chief of OTTVerse, a news portal covering technological and business news in the OTT space. With extensive experience in video compression, ABR streaming, video analytics, monetization, and more, Krishna has held multiple roles in R&D, Engineering, and Product ownership at companies such as Harmonic Inc., MediaMelon, and Airtel Digital. Krishna has published numerous articles and research papers on the latest trends in OTT and frequently speaks at industry events to share his insights and perspectives on the fundamentals and the future of OTT streaming.

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