This is a note to self about how to programmatically resize and crop many images using ImageMagick. It all started with a folder full of photos with different pixel sizes and ratios. That is because they had been captured with various cameras and had also been manually cropped. This could be verified by running this command to print their pixel sizes: identify -format "%wx%h\n" *.JPG Fortunately, all the images had a reasonably large pixel count, so I decided to go for a 5MP pixel count (2560x1920 in 4:3 ratio).

We are organizing the Rhythm Production and Perception Workshop 2021 at RITMO a week from now. Like many other conferences these days, this one will also be run online. Presentations have been pre-recorded (10 minutes each) and we also have short poster blitz videos (1 minute each). Pre-recorded videos People have sent us their videos in advance, but they all have different first “slides”. So, to create some consistency among the videos, we decided to make an introduction slide for each of them.

In some recent posts I have explored the creation of motiongrams and average images, multi-exposure displays, and image masks. In this blog post I will explore different ways of generating keyframe displays using the very handy command line tool FFmpeg. As in the previous posts, I will use a contemporary dance video from the AIST Dance Video Database as an example: The first attempt is to create a 3x3 grid image by just sampling frames from the original image.

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.