The Definitive OTT AVOD Glossary

This blog post is only a section of Unreel’s complete OTT glossary covering over 100 key terms every successful streaming service needs to intimately understand.  View the entire glossary here. 


AVOD or advertising video on demand is not always easy for streaming services to implement.  It requires knowledge of current best practices and experience with the industry’s in’s and out’s to navigate.  Even with ad spend on OTT rapidly increasing year-over-year, predicted to grow almost two and a half times by 2021, we have yet to reach the critical mass necessary to mean that every ad call made is an ad call filled on OTT.  Until one hundred percent fill is achieved, it is a competition amongst streaming services to sell their inventory, and those with the most intimate understanding of the space have a major leg up.


Whether you are an ad ops expert or still learning about the industry, our AVOD glossary is a helpful guide that explains key terms and examines their significance from a streaming service’s perspective.


AVOD (Advertising Video on Demand)

Advertising Video on Demand is video content monetized through the delivery of video advertisements to a viewer before (Pre-Roll), during (Mid-Roll), or after (Post-Roll) the video.


SWAF – Subscribe to Watch Ad Free

Subscribe to Watch Ad Free is a hybrid monetization model combining both AVOD and SVOD. Users are served ads while viewing videos within a streaming service but have the option to pay a subscription to limit the frequency of, or completely disable ads. This can be offered in a tiered model, where users have the option of multiple subscription price points that determine the frequency of ads.


VAST (Video Ad Serving Template)

Video Ad Serving Template was developed by IAB (International Advertising Bureau) as a universal language for serving ads. It outlines standardized specifications for video ads so that no matter the ad server, an ad with a VAST tag can be delivered and streamed on compliant players.


VPAID (Video Player Ad-serving Interface Definition)

Video Player Ad-serving Interface Definition is a script that allows advertisers to insert higher value, customized ad formats, including interactive elements into video streams. It instructs the video player where to place actions including pause, play, length of ad and more. VPAID’s flexibility can result in video ads that are more effective which in turn means advertisers are willing to pay more for inventory. VPAID ads offer less tracking capabilities than VAST, although the two can be stacked for an optimized ad delivery system for advertisers.


VMAP (Video Multiple Ad Playlist)

Video Multiple Ad Playlist is an XML template used to establish the structure for ad insertion. It allows video content owners and ad networks to schedule multiple ad insertions from a single tag. VMAP is the guide that sets ad cadence, or specific ad breaks within content.


RAF (Roku Ad Framework)

Roku Ad Framework provides advanced advertising fulfillment and rendering capabilities to Roku applications. The library supports a variety of ad services, and rendering of both video ads and interactive ads while enforcing consistent user experience for all applications on Roku. The library is designed to support multiple use cases, providing streaming services with flexibility to control as little or as much of the ad rendering process as desired.


Ad Cadence

Ad Cadence is the frequency of ad-breaks specified within a content feed. Broadcast long-form content traditionally has an ad break every 7 minutes, whereas short-form web content may have shorter ad breaks every 3 minutes. Optimizing ad cadence for a minimally interruptive experience can significantly impact view times and user satisfaction.


SSAI (Server Side Ad Insertion or Ad Stitching)

Server Side Ad Insertion, also known as Ad Stitching, is a backend process to insert ads into videos prior to distribution to viewers. Videos and video ads have different points of origin, videos coming from a CDN and ads most often coming from an ad server. SSAI is the process of stitching ads into videos at appropriate cadences on the backend before the content is streamed to the viewer. This creates a smoother, uniform experience for all users. Server-side ads also circumvent ad-blockers, which are unable to distinguish an ad from the actual content, rendering them ineffective.


SSAI has two shortcomings in comparison to client-side ad insertion. Chiefly is a lack of targeting capabilities. Since the same feed of content and ads are distributed to all viewers, it is difficult to dial into audiences on a user-by-user basis with specific ads. Server-side Ad Insertion also relies on the streaming service to report views, since advertisers are unable to measure impressions themselves. This creates some concern with advertisers who worry about the accuracy of reports.


CSAI (Client Side Ad Insertion)

Client Side Ad Insertion is when ads are served during ad breaks on the applications side. This means when a user reaches an ad break, a call must go out for that specific user. This provides advertisers with better tracking around their ad. Another major advantage is that since the call is for a specific user, DAI ads can be inserted to target the specific user. However, this is a slower process, which can lead to longer load times during the ad call. In general, CSAI is a less seamless experience than SSAI, but does allow for more accurate targeting.


DAI (Dynamic Ad Insertion)

Dynamic Ad Insertion is technology that enables advertisers to deliver video ads on a user-by-user basis. Instead of serving the same ad to every viewer, DAI allows for different ads to be shown to different viewers based on targeting. This means viewers are shown ads more relevant to them, providing more value for advertisers, and a better experience for users.


Ad Pod

An Ad Pod is a group of video ads that appear together during an ad break. Each Ad pod consists of multiple ad calls and each video ad delivered in a pod is considered an individual impression. The number of ads delivered in an ad pod can have a major impact on user experience.


Video SSP (Supply Side Platform)

Video Supply Side Platforms allow streaming services to sell their ad inventory in an automated fashion. The function of an SSP is to maximize CPM’s and fill rates for the streaming service. Since SSP’s handle selling ad inventory, it is not required for streaming services to manually contact advertisers and directly sell their inventory; a less efficient process that requires expensive sales people. In cases where manually selling of inventory is taking place, an SSP can still be used to sell any remaining inventory.


SSP’s works by plugging the streaming service’s ad inventory into multiple ad exchanges, DSP’s and networks. SSP’s are often called yield-optimization platforms, because they expose ad inventory to the greatest numbers of marketers, increasing the opportunities for higher bids for inventory, all automatically.


Video DSP (Demand Side Platform)

A Demand Side Platform is a system enabling advertisers to manage their bidding and delivery of ads across multiple ad exchanges in one interface. DSP’s are important for streaming services because they are the means by which most advertisers bid and track bought inventory on OTT.


CPM (Cost per Thousand or Mille)

CPM measures the cost of one thousand ad impressions. The CPM is the amount advertisers pay for one thousand ad impressions and they vary drastically based on the platform. Typically video ads on CTV draw some of the highest CPM’s in the marketing industry.


Floor CPM

Floor CPM is the minimum CPM bid a streaming service will accept to sell their ad inventory for. It is usually a number that can be set on the streaming service’s SSP.


In-stream Ad

In-stream Ad’s are video ads played around or during a video stream. They can appear before the start of a video (Pre-Roll), during a video (Mid-Roll), and after a video (Post-Roll).


Ad Inventory

Ad Inventory is the total number of available ad requests or “calls” a streaming service makes. Ad inventory is “filled” by ad impressions.


Ad Impression

An Ad Impression is when an ad has been delivered and displayed within a streaming service on a device.


Audience Extension

Audience Extension allows multiple streaming services with similar audience segments to group their ad inventory, making the inventory more desirable and valuable to advertisers, driving demand and CPM’s


Ad Exchange

An Ad Exchange is a platform where streaming services can auction and track their ad inventory to interested advertisers. Streaming services can plug their ad inventory into multiple ad exchanges using an SSP.


Ad Call or Request

An Ad Call or Request occurs when content in a streaming service reaches a specified ad break in content resulting in a “call” to deliver ads. Every ad call within a streaming service makes up that service’s ad inventory.


Fill Rate

Fill Rate, or “fill” is the percent of times an ad call is received and an ad is delivered resulting in an ad impression. A very low fill rate could signify a streaming service may have a CPM floor that is too high. Conversely, a very high fill rate might be the result of a undervalue CPM floor. Fill rate percent can be calculated by dividing ad Impressions by ad calls and multiplying that dividend by one hundred.


Ad Frequency

Ad Frequency is how often a user is shown the exact same ad. Serving the same ad multiple times to the same user is repetitive and can negatively impact the effectiveness of the ad and the user’s experience. Frequency capping limits the number of times a user can see the same ad.



Sponsorships on streaming services are promotional opportunities within a streaming service that go beyond programmatic in-stream ads. Often times, sponsorships involve promotional brand placement in prominent places within the streaming service including in-stream ads and banner ads that feature copy such as “presented by” or “sponsored by.” Sponsorships must be sold directly by the streaming service and in most cases are highly coveted by brands, who view them as a higher impact channel than simple advertisements.


Native Ads

Native ads are advertisements within a streaming service that seek to be as unobtrusive as possible. They achieve this by blending the advertisement as best as possible into normal functionality of the streaming service.


Ad Reach

Ad Reach measures how many people were served an advertisement. Ad reach totals differ from total ad impressions, in that the same ad can be shown to the same person multiple times, increasing ad impressions but not reach. In the case of many OTT devices, multiple individuals may be watching the same screen, so when an ad is served, only one impression is recorded, however, the reach was greater than that since more than one person saw the ad.


Waterfall Advertising

Waterfall Advertising, also known as water falling, waterfall tags or daisy chaining, is a process that helps streaming services sell their entire ad inventory at the best possible CPM’s. It is a multi-step system that allows streaming services to make calls to multiple locations in order of highest valued advertisements. With a waterfall technique, an ad call will first be made to an ad exchange or ad network with the most premium advertisers, if they are unable to fill the ad call, the ad call then goes to the next highest rated exchange or network. This process will continue until all possible marketplaces have received the ad call. This technique optimizes the fill rate and CPMs.


Ad Ops (Ad Operations)

Ad Operations is a department or individual working within or on behalf of a streaming service to fill ad inventory. Their focus is to set up, manage and track systems to sell ad inventory to advertisers.


Addressable TV Advertising

Addressable TV Advertising is the ability to display different ads to different users all watching the same live programming based on the household’s demo and psychographics. This form of DAI on the server side (SSAI) is extremely valuable to advertisers, affording them with strong targeting capabilities.


Programmatic Advertising

Programmatic advertising is the buying and selling of ad inventory through the use of software automatically. With programmatic ads, advertisers and publishers are able to efficiently navigate the marketplace; requiring less direct interactions and effort.


Skippable Video Ads

Skippable Video Ads are video ads that are skippable by users, either right at the start or after a certain period of time. Advertisers will pay lower CPM’s for ads that have been skipped, but higher CPM’s for skippable ads that are completed, as it infers the user was engaged.


VCR (Video ad completion rate)

Video ad completion rate is the rate at which video ad impressions play to 100%. An ad is not considered completed if a user skips an ad, or exits a video during an ad.




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