Remember the last time you felt terrified during a horror movie? Take that moment, and all the suspense leading up to it, and imagine it individually calibrated for you. It's a terror plot morphing in real time, adjusting the story to your level of attention to lull you into a comfort zone before unleashing a personally timed jumpscare.

Or maybe being scared witless isn't your idea of fun. Think of a rom-com that stops from going off the rails when it sees you rolling your eyes. Or maybe it tweaks the eye color of that character finally finding true love so it's closer to your own, a personalized subtlety to make the love-struck protagonist more relatable.

You can thank (or curse) 5G for that.

When most people think of 5G, they're envisioning an ultra-fast, high-bandwidth connection that lets you download seasons of your favorite shows in minutes. But 5G's possibilities go way beyond that, potentially reinventing how we watch video, and opening up a mess of privacy uncertainties.

"Right now you make a video much the same way you did for TV," Dan Garraway, co-founder of interactive video company Wirewax, said in an interview this month. "The dramatic thing is when you turn video into a two-way conversation. Your audience is touching and interacting inside the experience and making things happen as a result."

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The personalized horror flick or tailored rom-com? They would hinge on interactive video layers that use emotional analysis based on your phone's front-facing camera to adjust what you're watching in real time. You may think it's far-fetched, but one of key traits of 5G is an ultra-responsive connection with virtually no lag, meaning the network and systems would be fast enough to react to your physical responses.

5G is on the cusp of reality, with the first compatible smartphones set to debut next year. And while these forms of media don't even exist yet, the potential for them is huge, according to one estimate. 5G will propel annual revenue from immersive and new media applications from zero to $67 billion within a decade, according to a forecast by Ovum commissioned by Intel.

For context, that matches the value of the entire mobile media market – video, music and games – last year. Overall, Ovum and Intel predict 5G will more than triple the mobile media market worldwide, reaching $420 billion in 2028 from $170 billion this year.

Generational leap

Before you cast a skeptical eye at 5G, consider how the last explosion of mobile connectivity, from 3G to 4G LTE, changed how we consumed video. Being able to watch -- and in YouTube's case, upload -- video on a mobile device reimagined how we watch TV and the types of programming that are big business. A decade ago, when Netflix was about two years into its transition to streaming from DVD mailings, its annual revenue $1.4 billion. This year it's on track for more than 10 times that ($15.806 billion).

"The widespread availability of 4G enabled a massive improvement of distribution of video," said Jim Spare, the chief operating officer of interactive video company Eko. "With 5G, new forms of video media entirely can be delivered into a mobile setting."

5G's potential for video is based in several major changes to how video is distributed and created. The biggest are 5G's low latency, or the lag time between when you call up a page and when the network responds. The lag time with 4G is about 20 milliseconds, but 5G can cut it down to as little as 1 millisecond.

The technology is also better at handling huge amounts of data. Video is already one of the most data-heavy activities online -- it's almost 58 percent of the downstream traffic on the internet this year, according to Sandvine.

5G not only lightens that load, but it also can make new kinds of video accessible.

One simple application is like DVD extras on steroids. Garraway gave the example of Jurassic World, a blockbuster with hundreds of digital assets that never made it into the final cut of the film. Crane rigs that captured sweeping shots over the park, for example, also had 360-degree cameras attached underneath. But hardly any of those assets were seen, Garraway noted.

An "interactive movie means that you could relive that [footage] in the time that you're watching the movie, switching cameras on the fly," he said. The speed and capacity of 5G also make it possible for video to be created in real time according to your responses. As films and shows are are increasingly computer-generated, characters become malleable.

Taking your cues

But some homes today have fat, fast internet pipes similar to 5G already, so why aren't these kinds of media happening already? The difference is how much more powerful a mobile device is at collecting information. Phones have touchscreens, cameras, mics, GPS and gyroscopes, and you take them with you everywhere. That makes it easier to get intel about what you want, where you are and what you're doing.

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So when Claire Underwood speaks straight to the camera in House of Cards, you could answer back -- and get a response.

5G's mobility can bring video experiences to new locations. Spare gives the example straight out of Minority Report, of entering a Gap retail store and being greeted by name. But taken further, the store could develop a three-dimensional video concierge for your phone -- a pseudo-hologram that helps you find what you're looking for. With 5G's ability to make virtual and augmented reality more accessible, you could get a snapshot of what an outfit might look like on you without having to try it on.

Where things get crazy -- and creepy -- is imagining how 5G enables video to react to your involuntary cues and all the data you unconsciously provide. A show could mimic the weather or time of day to more closely match the atmosphere in real life.

For all the eye-popping possibilities, 5G unleashes a tangle of privacy questions. 5G could leverage every piece of visual information a phone can see on cameras front and back in real time. This level of visual imagery collection could pave the way for video interaction to happen completely automatically.

It's also a potential privacy nightmare.

As these technologies are realized, Garraway advocates for in-the-moment disclosure. "If I'm watching an interactive experience and it's reacting to me emotionally, it should tell you when it's starting to do that. Don't ask at the beginning when I don't know what it means," he said.

But the lure of billions of dollars have already encouraged companies to make privacy compromises.

And that may make it feel like your personalized horror show is already here.

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