Keyframes

I use a GoPro Max 360-degree camera in my annual #StillStanding project. This has given me plenty of opportunities to work with GoPro files and explore their structure. Previously, I wrote about the various files generated when recording. In this post, I’ll focus on how keyframes work in GoPro Max recordings and how to extract keyframe information. What is a Keyframe? A keyframe (also known as an I-frame) is a frame in a video that contains a complete image, unlike other frames (P-frames and B-frames) that only store changes from previous or future frames. Keyframes are essential for video editing, seeking, and compression. ...

As part of my exploration in creating multi-exposure keyframe image displays with FFmpeg and ImageMagick, I tried out a number of things that did not help solve the initial problem but still could be interesting for other things. Most interesting was the automagic creation of image masks from a video file. I will use a contemporary dance video from the AIST Dance Video Database as an example: The first step is to extract keyframes from the video file using this one-liner ffmpeg command: ...

While I was testing visualization of some videos from the AIST database earlier today, I wanted to also create some “keyframe image displays”. This can be seen as a way of doing multi-exposure photography, and should be quite straightforward to do. Still it took me quite some time to figure out exactly how to implement it. It may be that I was searching for the wrong things, but in case anyone else is looking for the same, here is a quick write up. ...