Answerman

Why Do I See Different Ads When Streaming On A PC Versus A Device?

Wayland asks:

This might be a more region specific question that I realise, but I've noticed a difference in the advertisements aired when I watch anime on crunchyroll. When I watch it on my computer it has region specific advertising (ie. Australian ads telling me to save on car insurance) but when I cast it to my TV it only has crunchyroll ads for other shows they have. I don't subscribe to more conventional streaming websites, so I don't have much to compare it to.

Video advertising, especially advertising that comes in from ad networks, is a tricky beast. When an ad is served, you aren't just being redirected to another short video before your desired content plays. A server has to determine what ad to serve to you, based on your location, time and date, the amount of ads that are left in the bucket, and what sort of content the ad is being played with. Once an ad is selected for you, the video player software has to get served with a bunch of data: where to find the video file, a URL for what happens if you click the ad, a tiny hidden pixel that's used to track whether or not the ad got displayed, and all sorts of back-and-forth communication between the end user and the ad server. It's all very complicated.

Most websites serving video aren't directly selling advertising, themselves. Instead, they relay on an ad network, which is a company that sells video ad slots in huge numbers to major companies, and then divides those ads up between the affiliated websites that it represents. For many years, these ad networks had to come up with their own technology to manage and serve these ads, and their methods for doing so all required adding some secret sauce to the video player that runs in the web browser. These technologies were completely incompatible with each other -- it was the wild west.

After a surprisingly long time, the Interactive Advertising Bureau (IAB) -- the advertising standards body in charge of internet advertising -- came up with a standardized format called VAST. VAST is a unified set of tools that uses a combination of video files and XML to serve ads in a unified way. Originally VAST was a technology that only worked over Flash, but it has since been implemented via HTML5 and set-top boxes. Over the years VAST has been enhanced with an interactivity layer called VPAID, and now covers formats ranging from pre-roll ads (the ads before the video), mid-roll middle of the video) and post-roll (after the video) to banner overlays and "companion" ads that display elsewhere on the page.

VAST format ads are a pretty complex operation, and the format has not been implemented across every platform. Indeed, they are really intended to work within a web browser. While other devices, such as Android and iOS devices can serve them as well, other means of watching streaming content can be a bit more of a challenge. The particular scenario you describe, where you're casting the stream to a television, presents a particular challenge: how does the ad tracking work when the ad itself is displayed on a completely foreign device?

In circumstances like these, the Crunchyroll ad server is smart enough to go, "oh, I guess these network ads won't work with this current configuration. I guess we'd better just serve up some in-house ads instead -- those don't matter if they get tracked successfully or not."

Yes, this subject gets insanely technical and complex. No, I do not miss it.

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Anime News Network founder Justin Sevakis wrote Answerman between July 2013 and August 2019, and had over 20 years of experience in the anime business at the time. These days, he's the owner of the video production company MediaOCD, where he produces many anime Blu-rays. You can follow him on Twitter at @worldofcrap.