Key takeaways
- SSAI stands for Server-Side Ad Insertion, a technology that inserts advertisements into a video stream before the content reaches the viewer's device.
- SSAI is also known as server-side ad stitching because it combines advertising and content into a continuous playback experience.
- SSAI is commonly used in OTT, Connected TV (CTV), live streaming, and FAST services.
- Unlike Client-Side Ad Insertion (CSAI), SSAI manages ad insertion through server-side infrastructure rather than relying on the application or player to switch between content and advertisements.
- SSAI can improve ad transitions and simplify playback across different devices, but it also introduces challenges around measurement, ad personalization, and infrastructure.
- Successful SSAI implementation requires coordination between video workflows, ad decisioning, delivery, measurement, and applications.
Server-Side Ad Insertion (SSAI) is a widely used technology for delivering advertising within streaming video.
For OTT providers, broadcasters, and Pay TV operators, advertising is no longer limited to traditional commercial breaks. Streaming services can use ad decisioning technology to select advertisements based on available inventory, content, and permitted audience information.
But selecting the right advertisement is only part of the process.
The ad also needs to play reliably, transition smoothly into and out of content, and generate accurate measurement data.
SSAI addresses an important part of that challenge by managing ad insertion on the server side.
So, what exactly is SSAI, how does it work, and when should streaming providers use it?
What is SSAI?
SSAI (Server-Side Ad Insertion) is a method of inserting advertisements into streaming video through server-side infrastructure before delivering the stream to the viewer.
Rather than requiring the viewer's application to separately request and play each advertisement, an SSAI system prepares a stream that includes both content and advertising.
The video player then receives a playback experience in which ads are incorporated into the streaming workflow.
SSAI is sometimes called server-side ad stitching or dynamic ad insertion (DAI), although dynamic ad insertion is a broader term that can describe multiple approaches to selecting and placing advertisements.
SSAI is particularly relevant for services delivering video across multiple connected TV devices, where player behavior and advertising integrations can vary.
How does SSAI work?
SSAI works by identifying an advertising opportunity, requesting an appropriate advertisement, preparing it for delivery, and incorporating it into the video stream.
A typical SSAI workflow involves six stages.
1. The viewer starts watching
A viewer selects a video, joins a live stream, or opens a FAST channel.
The streaming platform identifies the playback session and any relevant advertising opportunities.
2. An ad break is identified
The streaming workflow identifies an available advertising position.
This might be a pre-roll before an on-demand video or a scheduled break during a live channel.
For live and linear services, ad opportunities may be signaled through technologies such as SCTE-35 markers.
3. The SSAI system requests an advertisement
The SSAI service communicates with an ad server or advertising decisioning system.
The request can include relevant information such as content type, ad break duration, device information, and permitted audience signals.
The ad server determines which advertisement is eligible for the opportunity.
4. The advertisement is prepared
The selected ad creative must be compatible with the streaming workflow.
This can involve preparing or transcoding the advertisement to match relevant video and audio requirements.
Compatibility matters because differences between the advertisement and the main content can create playback problems.
5. The advertisement is stitched into the stream
The SSAI system incorporates the advertisement into the stream delivered to the viewer.
For adaptive bitrate streaming, this often involves modifying the stream's manifest or playlist so that the player requests advertising segments at the appropriate time.
The player can continue using its normal streaming playback mechanism.
6. Playback and measurement take place
The viewer watches the advertisement as part of the streaming session.
The advertising system records relevant events for campaign reporting, billing, and optimization.
Depending on the implementation, measurement may involve server-side tracking, client-side events, or a combination of both.
The simplified SSAI process is: Viewer requests content → Ad opportunity identified → Ad selected → Creative prepared → Ad stitched into stream → Playback and measurement.
What is the difference between SSAI and CSAI?
The main difference between SSAI and CSAI is where advertising insertion is managed.
SSAI inserts advertisements through server-side infrastructure.
CSAI (Client-Side Ad Insertion) uses the viewer's application or video player to request and manage advertising playback.
Neither approach is universally better.
The right choice depends on the devices being supported, advertising formats, measurement requirements, existing infrastructure, and commercial strategy.
What are the benefits of SSAI?
1. Smoother transitions between content and advertising
SSAI can reduce the need for the player to switch between separate content and advertising playback paths.
This can create more consistent transitions, particularly on connected TV devices.
However, smooth playback still depends on correct stream preparation, compatible ad creatives, and reliable delivery.
2. More consistent advertising across devices
Streaming services need to support different smart TV operating systems, set-top boxes, streaming devices, mobile applications, and browsers.
By moving part of the insertion process to the server, SSAI can reduce reliance on device-specific advertising logic.
This does not eliminate all client integration requirements, particularly for measurement and interactive features.
3. Support for live and linear advertising
SSAI is well suited to streaming environments where advertising must align with scheduled breaks.
This makes it relevant for live sports, news, linear OTT channels, and FAST services.
4. Greater control over ad delivery
Server-side insertion gives operators a centralized point for managing aspects of ad stitching and delivery.
This can help maintain consistency across multiple streaming environments.
5. Reduced exposure to some client-side ad blockers
Because advertising is incorporated into the video stream, SSAI may be less susceptible to certain client-side ad-blocking methods.
However, SSAI does not guarantee that every advertisement will be delivered, viewed, or measured successfully.
What are the challenges of SSAI?
SSAI offers important advantages, but it also introduces technical and operational considerations.
Advertising measurement
Because advertisements are stitched server-side, the advertising system may not automatically know whether the viewer actually watched every segment.
Server-side tracking alone can produce measurement discrepancies if playback stops, the viewer changes channels, or the session ends unexpectedly.
Reliable measurement may require coordination between server-side events and client-side playback signals.
Ad creative compatibility
Advertisements need to meet the technical requirements of the stream.
Differences in encoding, audio formats, resolutions, or segment structure can create playback issues.
Personalized advertising
SSAI can support personalized advertising, but individualized ad decisions may require session-specific manifests or other delivery logic.
This can increase complexity around caching, scaling, and session management.
Infrastructure requirements
SSAI introduces additional processing and coordination between video workflows, ad servers, stitching services, and delivery infrastructure.
Operators need to consider performance, scalability, monitoring, and operational costs.
Interactive advertising
Some interactive ad formats depend on functionality within the viewer's application.
SSAI may therefore require additional client-side capabilities to support those experiences.
How is SSAI used in FAST streaming?
SSAI is commonly used in FAST because FAST services deliver scheduled linear channels with advertising breaks.
FAST stands for Free Ad-Supported Streaming TV.
A FAST channel typically follows a programming schedule, similar to traditional linear television.
Advertising opportunities can be identified within that schedule and filled dynamically.
For example, two viewers watching the same FAST channel may receive different advertisements during the same commercial break, depending on the service's ad decisioning and delivery architecture.
SSAI helps incorporate those advertisements into the streaming experience without requiring the player to manage every transition independently.
For FAST operators, the wider workflow also needs to coordinate channel scheduling, ad-break signaling, ad decisioning, and measurement.
How is SSAI used in CTV advertising?
Connected TV advertising refers to advertisements delivered through internet-connected television devices.
SSAI is particularly relevant in CTV environments because applications run across a fragmented range of operating systems, players, and hardware.
Managing ad insertion server-side can reduce some of the differences between device implementations.
For example, a streaming service may use SSAI to deliver advertising within the same content experience across multiple smart TV applications.
However, operators still need to consider device-specific playback behavior, measurement, and application requirements.
SSAI simplifies certain aspects of delivery; it does not remove the need for reliable multi-device testing.
Can SSAI support personalized advertising?
Yes. SSAI can support personalized or dynamically selected advertisements by requesting ad decisions for individual sessions or defined audience groups.
The available targeting signals may include:
- Content category
- Geographic information
- Device characteristics
- Permitted audience attributes
- First-party information, where appropriate
The level of personalization depends on the ad decisioning system, available data, consent, and delivery architecture.
Operators also need to balance personalization with the infrastructure requirements of managing individualized streams or manifests.
How is SSAI advertising measured?
SSAI measurement typically involves recording advertising events and determining whether ads were delivered and played.
Important metrics include:
Operators should distinguish between an ad being selected, stitched into a stream, delivered, and actually viewed.
These events are not necessarily equivalent.
Accurate reporting depends on the measurement architecture and the signals available from both server-side systems and playback devices.
What should operators consider before implementing SSAI?
Before choosing an SSAI solution, streaming providers should evaluate several practical questions.
- Does the solution support our VOD, live, and FAST requirements?
- Can it integrate with our existing ad server and demand partners?
- How are advertising opportunities signaled and managed?
- Does it support the streaming formats and devices we use?
- How are ad creatives prepared for compatible playback?
- What measurement methods are available?
- How does the system manage individualized advertising?
- What are the implications for CDN caching and delivery?
- How does it handle failed ad requests or unavailable creative assets?
- Can the infrastructure scale during major live events?
These questions help operators evaluate SSAI as part of their wider streaming architecture rather than as a standalone advertising feature.
SSAI within 24i Video Cloud
24i Video Cloud brings together content management, video workflows, personalization, monetization, applications, and data within a connected streaming ecosystem.
24i Advanced Advertising supports advertising capabilities, including server-side approaches, within the wider streaming environment.
For OTT providers, broadcasters, and Pay TV operators, this connected architecture can help align advertising with video delivery, applications, and audience experiences.
A modular approach also allows operators to integrate existing advertising and video technologies where appropriate.
The goal is not simply to insert more advertisements, but to support monetization without introducing unnecessary friction into the viewing experience.
Conclusion
Server-Side Ad Insertion (SSAI) is a technology for incorporating advertisements into streaming video before the stream reaches the viewer.
It is widely used in OTT, CTV, live streaming, and FAST environments because it can support more consistent ad delivery and smoother playback transitions.
However, SSAI also requires careful consideration of creative compatibility, measurement, personalization, infrastructure, and scalability.
For streaming providers, the best approach is to evaluate SSAI as part of the complete video and advertising workflow.
With 24i Video Cloud, operators can connect content management, video workflows, personalization, monetization, applications, and data within a modular streaming ecosystem.
Looking to improve advertising delivery across your streaming service? Talk to 24i.
FAQs
What does SSAI stand for?
SSAI stands for Server-Side Ad Insertion. It is a method of incorporating advertisements into streaming video using server-side infrastructure.
What is server-side ad stitching?
Server-side ad stitching is another term for SSAI. It describes the process of incorporating advertising segments into the video stream delivered to viewers.
How does SSAI work?
SSAI identifies an advertising opportunity, requests an eligible advertisement, prepares the creative, incorporates it into the stream, and supports playback and measurement.
What is the difference between SSAI and CSAI?
SSAI manages ad insertion through server-side infrastructure, while CSAI uses the viewer's application or video player to request and play advertisements.
Is SSAI better than CSAI?
Not necessarily. SSAI can improve playback continuity and reduce some device-specific integration requirements, while CSAI can offer more direct control over client-side advertising and interactions.
Does SSAI prevent ad blocking?
SSAI may reduce exposure to some client-side ad-blocking methods because advertising is incorporated into the stream. However, it does not guarantee protection from all blocking or delivery failures.
Can SSAI be used for live streaming?
Yes. SSAI is commonly used for live streaming, including sports, news, and linear channels where advertising must align with scheduled breaks.
Is SSAI used in FAST?
Yes. FAST services frequently use SSAI to incorporate dynamically selected advertisements into scheduled linear streaming channels.
Can SSAI deliver personalized advertisements?
Yes. SSAI can support individualized ad decisions using permitted contextual, device, geographic, and audience information, depending on the implementation.
What are the main challenges of SSAI?
Common challenges include measurement accuracy, ad creative compatibility, session management, infrastructure scalability, and support for interactive advertising.
How does 24i support SSAI?
24i Advanced Advertising supports server-side advertising approaches within the wider 24i Video Cloud ecosystem, helping operators connect advertising with video workflows, applications, and audience experiences.
