So you've been filming video with your GoPro and want to extract a single image. Video is simply 30 jpeg images packed together per second. Here's how to achieve this at the highest quality possible. In order to keep every pixel gathered from the video camera you need to follow these steps...
Film in the highest resolution possible. If your camera does 4K at 15 or 30 fps, choose this. 4K video equals (30) 8MP JPGS per second. 8MP is enough to print! If your camera doesn't have 4K, then select 1080P. 1080P video footage is (30) 2MP images and still looks great for smaller prints and Instagram/Facebook.
Grab Still Image
Import video footage into Lightroom and click the shortcut "G" to visit the Library tab. From here, locate the video. Note: Videos won't play in the Develop tab. Now here's the secret very few people know....click the gear icon to the right of the play bar, this opens up the hidden image-grabbing tools! Now play the video until you find the exact frame, which can be very SLOOOW as Lightroom is not meant to play high resolution video. Now once you have the frame click the square box and CAPTURE FRAME.
You've extracted a still without any loss in quality!
Now hit "D" for the DEVELOP module. Here you will find the newly extracted clip. Edit this as you would a regular JPG image. Here's a few of my favourite video to still captures :)