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June 16, 2014

by Iain Anderson, macprovideo.com

macProVideo.com

The GoPro Hero line of cameras offer a high-quality way to capture footage that ordinary cameras can’t. They go underwater, they’re light enough to attach to helmets, they shoot at high frame rates for great-looking slow motion. Still, the fixed lens means you’re stuck with what you’ve got—a small sensor with a fish-eye wide field of view. If that fish-eye look bothers you, how can you get rid of it?

A frame from the original clip, in which I went surfing, and managed to stand up.

A frame from the original clip, in which I went surfing, and managed to stand up.

Learn to love it

Easy, if impractical: getting used to the look is the easiest path of all. If your client doesn’t mind it but you do, set aside your personal preferences and roll with it. You’ll get the best resolution and sharpest results, plus you won’t crop away any of your image. But if your client has noticed…

The official option

If you’ve never imported your footage into FCP X, you may have luck with the free GoPro Studio app.

It works if you take the files straight from the card, but not if they’ve been re-wrapped.

It works if you take the files straight from the card, but not if they’ve been re-wrapped.

However, when you import your footage into FCP X, the .mp4 that GoPro makes is re-wrapped into a .mov, and that apparently causes the fish-eye removal hidden in Advanced Settings to be unavailable in GoPro Studio. That’s a shame, though if you’ve dragged your footage into FCP X from the Finder (rather than using File > Import) you may not have problems.

Correct it with Photoshop

It seems like a less than obvious choice, but Photoshop can actually handle video as well as stills, and you can even apply its advanced lens corrections to video too. You’ll need the Exchange panel if you don’t have it already—here are some instructions. Install Exchange, restart Photoshop, then open the new panel from Window > Exchange.

Next, you’ll need a custom module to do the hard work. The latest one is called WideAngleVideo3, and you’ll need to search for that in the Exchange panel. Click the Free button to download it, then restart Photoshop to use it. (Note: if it doesn’t work after this step, restart your Mac too.)

Once you search, you’ll see this.

Once you search, you’ll see this.

Drag your video clip onto the Photoshop icon, or use File > Open and locate it. Choose Windows > Extensions > WideAngleVideo3, then look in the panel that appears and find the settings you used to record this footage. I’ve used a GoPro 3 Black at 1080p in Wide mode, which is good for video quality but bad for fisheye. Luckily, just pushing the button works a treat. Scrub through the video, and even take a look at the Adaptive Wide Angle filter that’s been applied (to a Smart Object) if you want to see how it works.

And here’s the button I need to press.

And here’s the button I need to press.

To export, use File > Export > Video, choose a destination and format settings (H.264 on high quality should be OK) and wait for the export. It can take a while, though.

And here’s the button I need to press.

And here’s the button I need to press.

Correct it with FCP X

Another strategy is to correct the footage a little closer to the editing process. First, download the trial of Lock & Load from CoreMelt. (Disclosure: I create tutorial videos for CoreMelt, but you can use the plug-in used here for free, even after the Lock & Load trial expires.)

Lens Undistort lets you pick the degree of correction you want to apply.

Lens Undistort lets you pick the degree of correction you want to apply.

In FCP X, add your clip to a matching timeline, then open the Effects tab. Look for C2 Lock & Load, then drag the Lens Undistort effect onto your clip. After a few seconds, it should deskew nicely, and you can adjust the Field of View parameter to match GoPro settings, or with Custom settings to match another camera instead.

This is much, much faster than the Photoshop method, but you have less control. Keep Photoshop ready for extra-tricky clips.

And here’s the corrected clip, which plays in real-time on my iMac.

And here’s the corrected clip, which plays in real-time on my iMac.

Next time, shoot with different settings

You have a couple of options to minimise the issue a little. You can either shoot on a “medium” or “narrow” field of view instead of the default “wide”, or shoot at a higher resolution to make cropping less deleterious to image quality. You can’t combine these settings, though: for the 2.7K resolution, you only have the “wide” option.

In 1080p mode you have a few options, and wide will be most distorted.

In 1080p mode you have a few options, and wide will be most distorted.

While going through the settings menus on the camera itself can be an exercise in frustration, it’s quite easy to find the settings in the companion iPhone app, so do it there if possible.

Conclusion

While the plug-in used here isn’t the only way to de-skew GoPro footage, it’s the easiest way I know, and it’s free. There’s another free FCP X plug-in from Alex4D that seems to do a good job too. So get out there and do something silly with your camera!*

*No, not that silly.

Find out more about the GoPro Hero range of cameras here:

http://gopro.com

 

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