AIP Trilogy: Pioneering the future of Advertising - Part 2

In part 1 of our trilogy, we discussed all the Benefits and Drawbacks of Client-Side Ad Insertion. In this article, we will dive into Server-Side ad insertion.

Weighing the Scale: Unpacking the Pros and Cons of Server-Side Ad Insertion

Roughly 10 years ago, but mostly used I would say since the last 5 years, another solution emerged which we know as server-Side Ad Insertion (SSAI).

The concept, as you can see above in the simplified diagram, is to send to each user a dedicated content manifest instead of the same manifest cached on the CDN. At specific positions, the ad break is typically signaled by SCTE-35 markers in the “broadcast” MPEG-TS-ts stream, and the content is replaced by advertising tailored to each viewer.?

What is the meaning from a technical and architectural point of view?

This is really changing a lot of important points. Firstly, the ad server call is initiated by the SSAI solution rather than the client, utilizing also as for CSAI, targeting parameters to personalize advertising for each user.?

The second technical impact is that the manifest is dynamically modified in “real-time” for each user, necessitating the SSAI solution and infrastructure to scale and follow the number of concurrent users.

The third point is that there is a real synchronization between the content and the position where the ad will be inserted, frame accurately. Of course, this is possible if the input stream also has the information at the right position, frame accurately, as it is done with SCTE-35 for exemple. If it is not the case, the SSAI solution is “just” following where the markers are located, if they are set at the incorrect position, the SSAI will not correct anything here.

We were one of the first in the market to work on SSAI solutions from 2017 with a production deployment at a major French broadcaster in 2018. From our extensive experience deploying this technology across Europe and the Middle East for multiple customers, we are, I think, perfectly well positioned to analyze the advantages and disadvantages of Server-Side ad insertion.?

Let’s start with the Pros of SSAI:

• Better user experience. As the advertising is “stitched” in the content itself, there is no latency, no buffering, there is just a perfect stream playing. Advanced SSAI solutions such as our DAIConnect product allow to manage the ad break creation with different rules to provide a TV-like experience as much as possible (please avoid the two or three minutes long slate with “we will be back soon”, as more smart options exist on the market).
• Enable new ad revenue on live. With the Client-Side only solution, the synchronization between the ad and the content is very difficult (you need to manage the load of the ad, sync the start of the ad at a specific position, and so on). With the introduction of SSAI in combination with SCTE-35 markers, customers have a better solution to enable the previously non commercialized ad break and inventory coming from TV live channels when consumed on OTT services.
• Ad Blocker bypass especially using server-side ad tracking. Another big improvement with the introduction of SSAI, is a way to avoid ad blockers for video consumption. As explained, the video player is “just” receiving a video stream with ads stitched in the content. There is no external call to ad servers done by the client video player, only a call to get the manifest. So if you block the only visible manifest call, you block the access to the content itself.
• No need to control or change or adapt the video player. This is also a very interesting point for broadcasters, publishers or content owners. Providing the same stream with SSAI compliant markers on all platforms allows the monetization for all thanks to SSAI. No need to have any integration with the different video players, saving a lot of technical and integration costs.
• Plays on all standard players without technical integration needed, as the SSAI solution will push a HSL or MPEG-DASH stream. If video players support these standards in a professional way, it will work on any player.

Looking back, I think that the three main drivers for the deployment at scale of such solution in the last five years, was:

1. The ability to do synchronized mid-roll ad replacement on live channels enabling new ad revenues
2. The ability for a content provider to enable advertising revenues without having to make any technical changes on the different distribution platforms they want to deliver their content
3. The ability to bypass Ad Blockers, as the ad server call is no longer done by the client but on the server-side.

But as with every technology, there are also downsides. As an SSAI provider, it is critical to have an honest view about it.?

Let’s list below these downsides of SSAI:

• SSAI is complex to implement. Yes, I am sorry to say that it is not “just” an ad server call as for CSAI. There is a strong link between the content stream format and the insertion of the ads in this stream for each user. There is an integration linked to the stream format (encoding / packaging) but also how the ad markers are inserted, signaled and formatted by the packager. If your stream is not perfect, perhaps that some video players will adapt and correct the issues when playing it without SSAI, but with an SSAI as proxy this will not be the case as it is processing and adapting the manifest “real time”. The SSAI solution will find all technical issue on your stream and the adaptation can then fail or make your player failing even if the problem is not at the SSAI level, but before in the chain and even if the input stream is playing in your video player (because this video player is correcting the problem as explained before). Your ad encoding format also needs to be set correctly to propose the best experience, but incorrect transcoding can lead to stopping streams or impacting the video quality for the end-user. Grabbing different stream formats from different providers without willing to standardize them as we see in a lot of cases in the FAST market for example, is of course working, but starting to manage ten’s of transcoding formats is not easy as sometimes codec are not the same. Markers formats coming out of the transcoders / packagers are also sometimes different as well. You need to understand that the SSAI is following the position of the SCTE-35 marker, so if this part is incorrect, the SSAI cannot be frame-accurate. To fix these synchronization issues, the customer will often need to engage with the “broadcast” team instead of the digital one. I will not list the different cases where we had to support our customers to reach the level of quality they were expecting but helping on the source MPEG-TS format or playout system. But I can say that our experience with the broadcast ad insertion part, is a major plus to quickly help our customers.
• You need markers and insertion points in live and VOD content. Many customers, especially on new OTT or FAST services, contact us to have ad insertion on their live feeds. Our first question is always, “Do you have any markers, such as SCTE-35, on these channels?”. And then, they realize that they have no markers, so their next question is: “Can we do ad replacement on ad breaks without markers?” The answer is globally : “No”. You can add an ad detection solution to add markers or you can have any other solution, but you need to have markers in the HLS or MPEG-DASH to do ad replacement correctly, because you need to cut the video chunk at the exact position to be frame-accurate. If we are talking about a professional solution, I am not talking about the quick and dirty ready to crash option of course.
• Need of a client-side implementation for enabling interactivity and ad click-through features. Many customers want to have Server-Side ad insertion. With regards to the ad tracking possibilities, the beauty of the SSAI solution is that if there are ways to do server-side ad tracking, you then don’t need to change anything on the video player side. That’s perfect. But... some customers want additional client side ad metrics or advertisers requests to have client-side ad tracking, which means, they need to send ad trackers client-side. Customers also sometimes, want to enable click-through features, especially on computer or mobile, allowing the user to click on the ads to visit the advertising website. To do all these features, you need to have a client-side implementation or an SSAI SDK at the client-side level. And of course, then the promise of no changes needed on the video player is no longer true.?
• SSAI is in the critical content delivery path. This is an important topic that needs to be explained. As the SSAI solution is acting on a proxy to deliver the manifest for all the users, any malfunction in this component can affect the totality of the users even if of course all major SSAI providers have robust implementation. This is why we develop and conduct regular load tests on our solution to mitigate such risks and ensure uninterrupted service for our customers. As the manifest is individually processed for each user, the solution must scale proportionally and at the same rate as the number of users joining the service. This is particularly true for high-demand events like sports games where users often join at the last minute. To address this level of performance, most SSAI solutions for major events anticipate and pre-scale the solution to meet this demand. As with cloud providers, auto-scaling solutions may not respond quickly enough to follow the huge peak of user increase (they sometimes need minutes to have machines active after the scaling demand). It is important to note that the CDN that has been deployed to guarantee the scalability on the content side is left on the side for the manifest with SSAI.
• Lack of important product features. It is not easy to admit, but for the last months or years, we've encountered customer demands that prove difficult to address with SSAI. Many requests revolve around the ability to manage long manifest in a cost-effective way on live channels. Processing long manifests for all users will for sure increase the computing and bandwidth costs. These bandwidth costs will not be charged as CDN costs but charged at full price as Internet bandwidth from the cloud computing machines. Other demands are complex to answer as well, not from a technical point of view, but again from an economical point of view, like the Ultra-Low latency support. Having partial chunks and calls that are multiplied by important factores, the number of requests on the SSAI infrastructure will for sure increase the cost of the solution. In the case of Video-On-Demand, the SSAI solution is making ad calls for all the ad insertion points or ad opportunities at the end-user’s play request, which is not optimal for managing the actual ad inventory available, nor for having ad trackers still active after more than one hour play or for having a good STR (Sell-Though Rate, a sell-side metric that is a ratio between the number of ads returned versus the number of ad impressions received) on your ad inventory.?
• SSAI can be costly. This is of course the crux of the game. As the infrastructure cost is directly linked to the number of users and the technical manifest parameters, the cost is mainly linked to the number of ads or slates inserted and the number of viewers or now, there is a big push from customers to have a model per impressions (when they have revenue). The number of companies that provide SSA Isolutions has also increased, and some have been bought by bigger companies. This market is now clearly in a price war, which is not good news, even for customers. You need to understand that as explained, SSAI is a critical component for video delivery to the end-user. Pushing the price really down as we see on the market since last year, will for sure, create delivery issues one day or another. Customers also think that when you have developed the solution, this is finished. No, standards are evolving all the time, and new features, data management, density need to be improved over time. But looking from the customer's point of view, yes, SSAI has an important cost to deliver the service, this is a fact.

As you can see each solution has its positive and its negative, as always.?

However, the beauty of technology lies in its constant evolution and innovation, with new ideas and solutions emerging to address challenges by leveraging advantages and minimizing drawbacks. This is precisely what's occurring with the introduction of a new ad insertion model, which we will discuss in part 3 of our trilogy.

Stay tuned for the last part of our trilogy to discover the next era of Dynamic Ad Insertion!