Webdriver Torso Explained — The Creepy YouTube Mystery Solved

For months a YouTube account called Webdriver Torso uploaded variations on the same eleven seconds. A red rectangle and a blue one appeared against white. The shapes changed size and position. A tone sounded. At the bottom of the picture, a counter advanced to the next slide. Then someone looking through the uploads came across six seconds of the Eiffel Tower lighting up at night.

The Paris clip offered something tens of thousands of test patterns could not. A real place appeared on camera, and a comment associated with the clip mentioned a person by name. By May 2014 reporters had two quite different ways to investigate the channel. They could ask an engineer what the rectangles were good for. Or they could follow the accounts behind the pictures and try to find someone who knew why they were there.

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The Timeline of the Webdriver Torso Mystery

September 2013. The series of rectangle-and-tone videos was under way. The date refers to the uploads rather than the creation of the account.
Early May 2014. The Guardian reported roughly 77,000 videos. A software tester recognized a possible use for them, then went back to check the example he remembered.
May 16, 2014. The Daily Dot reported an Italian blogger’s discovery of a network of related accounts and a possible connection to Google in Zurich.
June 6, 2014. Engadget published YouTube’s answer. Webdriver Torso was a way to check video quality.

Ten slides and a line of small print

The clips had enough in common that a viewer could recognize one without knowing anything about its maker. The slide count ran from 0000 to 0009. Each change supplied fresh positions for the two blocks of color and a different tone. The name aqua.flv appeared inside the frame. A visitor copying it down had recorded part of the picture. The title on the YouTube page was a different string of characters altogether.

It was a curious format for anyone hoping to find a message. The counter made it easy to line up the same moment in different uploads. Yet the pictures offered no key for deciding whether a change of pitch or the width of a rectangle stood for anything. Readers suggested espionage, advertising and even extraterrestrials. One comparison reported at the time was to the numbers heard on shortwave radio. An outsider might hear an entire transmission and still lack whatever the intended listener needed to understand it.

A tester remembers a demonstration

Isaul Vargas, a software tester, recognized something more ordinary in the clips. At an automation conference he had seen a demonstration involving set-top boxes, the devices that deliver television to a screen. The engineers needed a way to check how a video survived being uploaded. A simple changing pattern could give software something to look for in the returned picture. Vargas described the demonstration to the Guardian.

The recollection gave the reporters a lead they could check. Vargas retrieved the presentation, which came from the British company YouView. The clips in the slides resembled the ones on YouTube, but closer inspection showed that they differed. The Guardian updated its story. The demonstration helped explain why an engineer might produce videos like these. Identifying the person who ran this particular channel would take a different kind of evidence.

Even the account name could take an investigator only so far. WebDriver was a name familiar to people who automated browser tests. An early inquiry reached Patrick Lightbody, who had worked on the Selenium testing project. He denied that the project was responsible for the videos. Two leads had now pointed toward software testing without yielding an owner.

Following the accounts to Zurich

An Italian blogger writing as Soggetto Ventuno turned from what the videos contained to where they appeared. In May the blogger contacted the Daily Dot. A service that tracked YouTube channels placed Webdriver Torso in a network with the ungainly name ytuploadtestpartner_torso. Other accounts in its orbit posted similar short clips. Once there was a network to examine, the investigator could look for connections outside YouTube.

One trail ran through Google+, then to social profiles associated with people who worked for Google in Zurich. The blogger also compared office furniture visible in videos with pictures of the Zurich office. The Daily Dot described some material becoming unavailable as the account trail attracted attention. Those observations put a company and a city within reach. A desk phone, a social connection or a name in a comment could suggest where to ask the next question. None established who had operated the camera in Paris.

The people maintaining the channel also left viewers a joke. In an upload titled tmpRkRL85, the familiar blocks gave way to a dancing silhouette recognizable as Rick Astley. The choice worked because viewers had learned exactly what to expect next. It gave them an unmistakable exception to the pattern while leaving the purpose of all the other uploads unexplained.

The evidence that settled it

Engadget’s James Trew took the question to YouTube. On June 6 he published the company’s reply, which played on Astley’s song and confirmed that YouTube ran tests to guard against slow uploads and poor video quality. Trew described the operation in practical terms. A clip went up to YouTube’s servers. The version that came back could then be compared with the original.

That comparison gives the rectangles a purpose a casual viewer could easily miss. Imagine seeing the returned picture with one red block a little narrower than expected. Looking at that picture alone, there is no way to tell whether the block started out that way. Someone who has the original can put the two side by side. The question becomes quite specific: did the picture survive the trip? YouTube confirmed the purpose of the tests without publishing a specification for each shape, tone or slide.

Vargas had been close when he recognized the testing method. The blogger supplied a route to the organization that could confirm it. And the Eiffel Tower clip, the one piece of footage an ordinary viewer could immediately place, turned out to be much less revealing about the operation than the anonymous little rectangles. Their audience had the one piece viewers lacked: a copy of the picture as it ought to look.

Frequently asked questions

Who was behind Webdriver Torso?

YouTube confirmed to Engadget in June 2014 that it ran tests like these to check the quality of video uploads and playback. Investigators had traced associated accounts to people working for Google in Zurich.

What did an ordinary clip show?

Ten numbered slides showed red and blue rectangles against white, accompanied by changing electronic tones. The sequence lasted about eleven seconds.

Were there videos without rectangles?

Yes. Contemporary reporters documented the Eiffel Tower footage and a clip from the cartoon Aqua Teen Hunger Force dubbed in French. The channel also posted the Rick Astley visual joke.

Did anyone decode a message?

The explanation came from tracing the accounts and asking YouTube. Comparing a known source video with the version delivered back to viewers explained why an engineer could use such abstract pictures.