AWS for M&E Blog

Unlock increased monetization and lower TCO with server-guided ad insertion for VOD

Maximizing revenue while delivering exceptional viewing experiences is a constant pursuit in the world of video streaming. As advertisers shift focus to over-the-top (OTT) and connected TV (CTV) platforms, the value proposition between server-side ad insertion (SSAI) and client-side ad insertion (CSAI) for video-on-demand (VOD) content has changed. Previously, the primary benefits of SSAI were most apparent in live and linear streams. However, with the addition of new technology including server-guided ad insertion (SGAI), the scales are tipping in favor of server-side solutions, offering increased monetization rates, improved ad delivery, and superior viewing experiences—all at a lower total cost of ownership than CSAI.

Faster video start-up times with SGAI

Historically, one of the primary concerns with SSAI for VOD content was a longer video start-up time (VST), which could lead to higher viewer abandonment rates compared to CSAI and potentially negatively affect monetization. With the introduction of technologies such as HLS Interstitials and Penthera’s 2nd Look, SSAI now offers VST performance on par with CSAI, helping to eliminate this issue.

HLS Interstitials technology separates the delivery of ads from the delivery of content, an approach called serve-guided ad insertion (SGAI). With SGAI, the video content starts playing quickly while mid-roll ad breaks are prepared in the background. The player requests and inserts ads only when reaching the relevant ad break position in the stream. This provides for fast video start-up times, as there is no need to load the ads at the beginning of the video. Viewers can begin watching content immediately, ensuring a great user experience while also optimizing monetization for the publisher.

AWS Elemental MediaTailor is an SSAI service from Amazon Web Services (AWS) that uses HLS Interstitials to provide fast start-up times. While the player is playing the main content, MediaTailor works asynchronously to retrieve, transcode, and cache ads near the viewer, ensuring a consistent, high-quality ad experience when the ad break is reached. For an in depth how-to on implementing HLS Interstitials with MediaTailor read the Support for HLS Interstitials blog post.

With the addition of HLS Interstitials technology, SSAI technology is now clearly ahead of CSAI technology when viewed through the lens of total cost of ownership (TCO).

Reduce development and operational cost

When it comes to integration and maintenance, SSAI solutions like AWS Elemental MediaTailor offer a centralized approach, where ad insertion and video stitching occur on the server side. This approach streamlines the integration process and reduces the need for individual client-side implementations.

On the other hand, CSAI often requires integrating and maintaining proprietary SDKs across various platforms. This process can be resource intensive and costly. The centralized nature of SSAI also simplifies the maintenance efforts, as updates and modifications can be applied at the server level, eliminating the need for client-side updates across multiple devices and platforms.

Some platforms, such as CTV, run on constrained hardware and operating environments, making maintenance even more complex. By offloading the ad stitching process to the server, client devices are relieved from computational burden, resulting in a more efficient and consistent delivery of video streams. Using SSAI, publishers can allocate fewer resources to the development and operation of their ad insertion solution and focus instead on delivering high-quality content and optimizing ad strategies.

Improve scalability and agility

SSAI also offers scalability and flexibility advantages that are invaluable in today’s dynamic streaming landscape. With server-side ad insertion, content providers can manage ad campaigns centrally, streamline operations, and adapt to changing market conditions with agility. By modifying the streaming manifest for each viewer, SSAI ensures that the right ads are dynamically stitched into a content stream and personalized based on a viewer’s profile and preferences. This process is highly scalable and can accommodate hundreds of thousands or millions of viewers simultaneously.

SSAI platforms can dynamically scale resources up or down based on demand, ensuring optimal performance and cost-efficiency. SSAI architectures are also flexible and extensible, enabling content providers and ad tech companies to rapidly integrate new ad formats, targeting capabilities, and monetization strategies as they emerge.

Better monetization

SSAI not only helps publishers optimize their costs and become more agile, it also helps them better monetize their content. According to a report from Emarketer, CTV is the fastest-growing ad channel in the United States and advertisers are willing to pay a premium for CTV video ads inventory. Therefore, it’s important for publishers to choose an ad insertion solution that optimizes ad viewing rates and offers the best user experience for premium video ad campaigns.

SSAI solutions have several benefits. First, SSAI helps bypass ad blockers. By stitching ad content into the video stream on the server side before delivery, SSAI makes it difficult for ad blockers to detect and block ads. SSAI also provides the best experience for viewers. Adverts are transcoded into multiple renditions to match the resolution and bitrate of the content and delivered as a single high-quality video stream. By doing so, SSAI avoids buffering issues and a negative user experience caused by switching video quality between the primary content and the ads.

The video stream remains uninterrupted, providing a smooth viewing experience for the end-user. For this reason, SSAI generates better performance for advertisers. In a 2023 study, the company Conviva found that content completion rates are 5% to 10% higher for videos with server side ads. On top of this, as presented earlier in this blog post, SSAI through SGAI technology can now deliver fast video start-up times, which offers the best user experience and reduces startup abandonment rates. SSAI solutions such as MediaTailor offer both server-side and client-side ad tracking capabilities, enabling accurate measurement and the verification that is crucial for advertisers.

SSAI service AWS MediaTailor can also be combined with AWS partners solutions to leverage the benefits of HLS Interstitials.

Partner spotlight: CastLabs Player

CastLabs’ product, PRESTOplay for Addressable TV Ads is an extension of castLabs PRESTOplay suite, available across web (browsers, smart TVs, game consoles), Apple (iOS, iPadOS, tvOS), and Android (including Android TV).

Leveraging HLS Interstitials (and/or DASH Media Presentation Insertion Events), it is fully interoperable with AWS MediaTailor. This end-to-end hybrid client/server ad insertion scheme allows that only the ad manifest is returned to the player at the moment of the ad avail and not at the beginning of the VOD or catchup session as it’s the case in traditional SSAI scheme.

By decoupling programming manifest delivery from ads manifests delivery, content providers can optimize their advertisers’ campaign performances for VOD and catchup inventories.

SGAI and PRESTOplay for Addressable TV Ads leverage the best of both CSAI’s startup time and SSAI’s monetization advantages, offering a unified solution to overcome challenges encountered with either client-side or server-side ad insertion.

Partner spotlight: Penthera 2nd Look

Penthera’s product, 2nd Look, addresses the primary use cases of HLS Interstitial on VOD and, as a 100% cloud solution, does not require player support or modification to existing streams. 2nd Look enables just-in-time ad decisioning for existing VOD streams using SSAI and is available for both HLS and DASH, ensuring reach over the widest range of publishers’ devices.

2nd Look delivers the key benefits of just-in-time decisioning via a straightforward integration path. Publishers using the product see reduced video start times and significantly increased revenue performance when compared to industry-standard SSAI solutions. In the case of underfill, 2nd Look supports the truncation of ad pods as well as advanced features for presenting slate, if required. 2nd Look can also extend ad decisioning timeout windows and support complex ad inventory share arrangements.

For publishers looking to migrate from CSAI to SSAI, the combined solution of MediaTailor and 2nd Look streamlines the transition, retains fast video start times, and offers just-in-time decisioning typically associated with CSAI.

MediaTailor and 2nd Look, together, offer an innovative VOD SSAI solution with industry-leading features that improve the efficiency of ad decisioning and positively impact publishers’ bottom lines. 2nd Look is integrated with MediaTailor, runs on AWS services for scalability, and can be purchased via the AWS Marketplace.


The decision to adopt SSAI or CSAI for VOD content is a critical one, with far-reaching implications for revenue generation and viewer satisfaction. With the latest advancements in SSAI technology such as HLS interstitials (i.e. SGAI), the scales have tipped in favor of server-side solutions, offering increased monetization rates, improved ad delivery, and a superior viewing experience. By leveraging the power of SSAI, content providers and broadcasters can unlock new revenue streams, overcome ad blockers, and provide a seamless, high-quality experience for their audiences. The future of streaming is here, and SSAI is poised to be a driving force in this ever-evolving landscape.

Thomas Sauvage

Thomas Sauvage

Thomas Sauvage leads cross-functional, go-to-market initiatives to expand existing markets and develop scalable programs to drive adoption of AWS Media Services in the Asia-Pacific region.