Kevin Macdonald's YouTube movie nearing completion

A bare-footed skydiver hurtles towards earth in one of the submitted clips for Life In A Day - a film made by thousands of YouTube users

Many of us would be hard-pressed to remember what we were doing on 24 July this year.

But for many YouTube fanatics, amateur film and documentary makers, or even just those curious of a unique movie-making experiment, that day was the chance to produce a small part of cinematic history.

Kevin Macdonald, the Scottish director famed for The Last King of Scotland and Touching the Void, invited the vast YouTube community to spend a few moments filming their day.

Their clips were then collated and are currently being edited together by a team based in London's Soho district.

Some 5,000 hours of footage - 80,000 individual clips - have been sculpted into an hour and a half of feature film due to be premiered at January's Sundance Film Festival.

If that sounds like a monumental task, that's because it is. Joe Walker, the film's editor, told BBC Digital Planet's Snezana Curcic about the tiring process.

"In the time schedule we had, which was basically only a few months from start to finish, no one person could possibly see all that material.

"So the best thing we could do was set up an office with 24 researchers. Each of them was a very accomplished filmmaker, or somebody with some documentary or drama background."

The team sifted through the vast amounts of video, whittling it down to around 200 hours of the best submissions.

Although the majority of the clips had to be left on the cutting room floor, all the submissions will remain on YouTube in their dedicated Life in A Day portal.

'Extraordinary material'

The film, which is still being edited by Mr Macdonald and his team, is attempting to depict a "single day on earth".

"I keep saying that it's like one person's story," Mr Macdonald says.

"It's just that every time you cut that person's soul goes with you but the body stays behind. It's almost telling the story of the world as one person, but one person that keeps mutating in form."

Before the project began, Mr Macdonald realised that while it would be easy to get floods of content from the wealthy, tech-savvy youth of the Western world, for the film to truly represent the world they would have to reach out to less-enabled communities.

"For Life In A Day to be truly representative we felt we had to then do something about that. We went out and bought 400 plus cameras.

"Then we sent those cameras out to parts of Africa, Asia, Latin America - they were distributed to people in quite remote parts of the world.

"So some of the material is really extraordinary for that reason."

Despite all of the clips arguably having no relation to each other - other than the day of filming - Mr Macdonald has made some attempt to tie them all up as smoothly as possible.

"It was a full moon that day.

"So with the first opening sequence with the moon in various different countries - Malawi, South Africa, Australia.

"So you establish, right at the beginning, this idea that this is about the entire world at the same time. I don't think anyone has done a film like this. It hasn't been done before, and obviously it can only happen because of the new technology."

Darker side

Those technology hurdles provided ample headaches for Mr Walker, who had to deal with over 60 different frame rates - the speed at which a clip is shot - to make the entire production appear seamless.

He says the film is about much more than just your typical casual YouTube clip.

"This project has given us an opportunity to look slightly more in-depth.

"There is a darker side to the story as well, we have some very troubling material which came from the Love Parade in Germany, for example, where the fact that there were so many kids there with mobile phones and Flipcams means that we've got a YouTuber's view of a terrible tragedy taking place step-by-step."

More than 500 people were injured and 21 people were killed during a stampede at the dance festival in the city of Duisburg.

"There are some really shocking clips," adds Mr Macdonald.

"You are allowed in, for five minutes, ten minutes, to somebody's head who has a peculiar view of the way things function. There also are a few clips where you think this person needs help, not a camera."

Yet, despite some hard-hitting, emotional scenes, Mr Macdonald believes watching Life In A Day will be an uplifting experience.

"It's an optimistic film. It's a film about how wonderful it is to be alive."