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The State of Server-Side Ad Insertion 2018

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“For VOD content, some media companies incorporate a client-side ad SDK provided by the ad stitching service. The SDK typically provides an API that allows the application to know when individual ads start and end. In addition, these SDKs provide metadata about each ad that can be used for third-party ad tracking,” Xiques continues.

“In the absence of an SDK, you need some sort of marker. SCTE markers can be either included in the stream itself or the SCTE markers can be included as text in the manifest. Some application platforms don’t support SCTE natively. In these situations, if you are streaming HLS, ID3 tags which are native to HLS can be used,” notes Xiques. “In some cases, you may need service at the encoder to translate SCTE to ID3 tags before the stream is sent to the client.”

The Other AI

While there are a number of ways to find where to insert ads, advertising technology company Amagi has an ad insertion platform that programmatically identifies breaks for content that does not have SCTE markers. “We have an AI engine that can automatically identify where the ads are and replace them with a personalized ad,” says Srini KA, co-founder.

“[The machine learning system] is looking at video and audio changes, and saying ‘OK, is this something I identify as an ad?’ It takes an audio and video fingerprint of every frame, compares it against a fingerprint database, and says, ‘This is an ad that I already know,’” says KA. “The system learns by seeing thousands of ads and starts to distinguish ads apart from the content.”

How accurate is this? “Typically the system would miss the first or second instance of the ad,” says KA. “After it sees the same ad twice, then it knows it’s an ad because it follows a bunch of parameters.” These parameters include whether the content repeats multiple times, possibly across different channels, whether it is it short form (6 to 60 seconds), and whether the content ends with text or logos on screen.


After the content plays, the video player may refresh the user interface, take away the scrub bar, and put an ad countdown timer on screen. “When certain segments start to play, the player needs to say, ‘I’m not tracking content anymore, I’ve got to track these ads, and there’s certain ad metadata that I need to get a hold of then and send this out to Nielsen or ComScore or whomever you’re using to track this,’” says Xiques.

SSAI can take care of most of the data management and measurement attribution. What this means is that you can have a really light client and still monetize your content. That’s important for platforms and devices like Roku, Xbox, and PlayStation, where “you don’t want to be writing a bunch of client side code to be making just-in-time ad calls and parsing the VAST data and doing third-party tracking,” says Xiques.

“It’s important to view SSAI as the technique of stitching ads into content for delivery, and that there will always be complementary processes like measurement which support certain outcomes like sale of inventory,” says Tim Armstrong, senior product manager for server-side ad insertion at online video platform Switch Media. It has a product called AdEase for SSAI. “Some of the encountered problems come from large tech vendors who haven’t yet caught up with new solutions such as SSAI.”

“While we offer server-side tracking, client-side tracking is still currently the preferred method for this,” says Springall. “However, over the longer term, we predict a shift away from client-side tracking as the direct interaction be-tween device and some third-party end-points gives rise to some user privacy concerns.”

Artificial intelligence (AI) is increasingly being applied by companies like Amagi to identify where ads are and automatically replace them with personalized ads, as shown in this diagram. Image courtesy Amagi.


The ability to target both content and advertising is one of the biggest factors differentiating OTT from broadcast and cable. “There are no technical limitations on what you can do server side; it’s more what are you allowed to do for privacy reasons,” says Svensson. “It’s up to the operator how much data they want to reveal to do more targeted advertising.”

“SpotX can do the same audience targeting with SSAI that can happen in client-side ad rendering. That includes using first- and third-party data to identify, value, forecast, and transact on defined audiences. We are integrated with over 15 different SSAI solutions,” says Klosowski. SpotX claims to handle frame-accurate, data-driven ad insertion in more than a billion ad break opportunities each month in live and linear programming alone, not counting the additional VOD inventory. “For us, there isn’t a big difference in targeting abilities between client side or server side, because we have similar information available in either environment,” he says.

“SSAI permits the same one-to-one addressability as CSAI, but crucially gives the media owner greater control over what audience information is shared with the ad decisioning ecosystem,” says Springall. In CSAI, software in the client must be integrated that directly communicates with the ad decisioning ecosystem. “This raises two issues: The first means that your client software is tightly coupled with your ad tech ecosystem. If you want to make changes to your ad decisioning vendor, you have to make changes to the client applications,” he says.

“The second issue is that with so many devices that media owners need to provide support for, the cost of maintenance of implementing the solution for each device is becoming too high. That’s why we’re finding that media owners that have implemented SSAI for live are now turning to SSAI for their strategic AVOD [ad-supported video-on-demand] services.”

SSAI is well-suited for live video because of the lower latency it offers for delivering ad loads. But how can SSAI keep up with providing unique streams in large-scale live events? “Earlier this year we reported concurrency across all our customers of over 1.5 million, with each viewer receiving their own stream,” says Springall. “It’s not possible to request individual ad breaks for this number of users all at the same time, so our platform paces these requests ahead of the breaks to avoid overloading the ad decisioning ecosystem (for both first and third-party ad sources).” It’s safe to say, large scale personalization is not yet an option, but where is the industry moving on the ad standard side?

The VAST Horizon

The Video Player-Ad Interface Definition (VPAID), which is used mainly for desktop viewing and covers perhaps 10 percent of total video ad inventory according to Armstrong, is being phased out, and VAST has progressed to version 4. “The main change with VAST 4 has come with additional error codes, mezzanine file support, universal ad ID, a viewability node, and also supposed support for interactivity. VAST 4 also is the first time that SSAI has been included in a standard,” he says.

Updates to upcoming standard VAST 4.1 should help standardize ad requests through the use of macros to propagate context more easily, says Klosowski. In SSAI, there is no VPAID ad inventory. “While VPAID will continue to be used in the near future, VAST 4.1 takes the first steps to officially deprecate its use, significantly simplifying video ad execution and improving consumer experience,” he says. Also gone will be support for Flash ads. Other updates include the following:

  • A required AdServingID field has been added to simplify comparing data about a video impression across the various systems involved with the delivery and tracking of the impression.
  • VAST 4.1 introduces the concept of interactive templates, which work without ads being delivered with executable code, especially in mobile and OTT environments.
  • Standardized delivery of closed captioning files

Simplifying Ad Delivery at Scale

As mentioned earlier, SSAI drastically reduces the need for specialized, client-side development work to ensure the best playback experience from device to device. CSAI needs to be incorporated into the client code, and this isn’t a very scalable approach when the amount of devices being supported keeps growing. “[With SSAI] you can spend less time as a media owner developing custom technology for each individual platform. We have customers that support upward of 200+ types of devices and it’s very difficult to develop a client-side SDK for all of those environments,” says Klosowski. “All long-form content will be SSAI-enabled soon if it’s not already.”

Aside from the development challenges of supporting each and every variation of platform out there, CSAI just doesn’t work on some platforms. “With client-side ad insertion, the mobile device needs to load two video players at the same time in memory, and additional network requests (and potential round-trip latencies) for the communication with the ad server are added. On a thin device such as a Chromecast dongle, it is not possible to load two video players in memory at the same time,” says Xiques.

What’s Not to Love?

Finally, on the encoding side, a single adaptive bitrate feed works with a wide variety of device data requirements for HLS and DASH. “One of the key requirements for the system to work seamlessly is to be able to transcode in [close to] real time and deliver the right bitrate based on who’s watching, on what screen, what sort of bitrate are they getting, and what sort of aspect ratios and profiles they have on that device, so it looks exactly the same as the rest of the content,” says KA.

So server-side ad insertion combats ad blocking, requires fewer development resources, allows for a single adaptive bitrate (ABR) feed, and enables targeted online ad delivery and better personalization at lower latency. While SSAI has found the most use as a method for ad insertion into live content, it’s now gaining traction for VOD content as well. No matter whether it’s live or VOD, though, SSAI is better for both viewers and publishers.

[This article appears in the September 2018 issue of Streaming Media magazine as "The State of Server-Side Ad Insertion."]

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