Creating different types of keyframe displays with FFmpeg

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....

March 1, 2020 · 4 min · 761 words · ARJ

Creating image masks from video file

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:...

February 21, 2020 · 3 min · 510 words · ARJ

Creating multi-exposure keyframe image displays with FFmpeg and ImageMagick

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....

February 21, 2020 · 2 min · 419 words · ARJ

Visualizing some videos from the AIST Dance Video Database

Researchers from AIST have released an open database of dance videos, and I got very excited to try out some visualization methods on some of the files. This was also a good chance to test out some new functionality in the Musical Gestures Toolbox for Matlab that we are developing at RITMO. The AIST collection contains a number of videos. I selected one hip-hop dance video based on a very steady rhythmic pattern, and a contemporary dance video that is more fluid in both motion and music....

February 21, 2020 · 2 min · 320 words · ARJ

Testing simple camera and microphone setups for quick interviews

We just started a new run of our free online course Music Moves. Here we have a tradition of recording wrap-up videos every Friday, in which some of the course educators answer questions from the learners. We have recorded these in many different ways, from using high-end cameras and microphones to just using a handheld phone. We have found that using multiple cameras and microphones is too time-consuming, both in setup and editing....

February 14, 2020 · 5 min · 896 words · ARJ

Motiongram of high-speed violin bowing

I came across a high-speed recording of bowing on a violin string today, and thought it would be interesting to try to analyze it with the new version of the Musical Gestures Toolbox for Python. This is inspired by results from the creation of motiongrams of a high-speed guitar recording that I did some years ago. Here is the original video: From this I generated the following motion video: And from this we get the following motiongram showing the vertical motion of the string (time running from left to right):...

January 24, 2020 · 1 min · 108 words · ARJ

Podcast on Open Research

I was in Tromsø to hold a keynote lecture at the Munin conference a month ago, and was asked to contribute to a podcast they are running called Open Science Talk. Now it is out, and I am happy to share: Open Science Talk · #26 Music Research In this episode, we talk about Music Research, and how it is to practice open research within this field. Our guest is Alexander Jensenius, Associate Professor at the Department of Musicology Centre for Interdisciplinary Studies in Rhythm, Time and Motion (IMV) at the University of Oslo....

January 9, 2020 · 1 min · 149 words · ARJ

Teaching with a document camera

How does an “old-school” document camera work for modern-day teaching? Remarkably well, I think. Here are some thoughts on my experience over the last few years. The reason I got started with a document camera was because I felt the need for a more flexible setup for my classroom teaching. Conference presentations with limited time are better done with linear presentation tools, I think, since the slides help with the flow....

December 27, 2019 · 4 min · 785 words · ARJ

Creating individual image files from presentation slides

How do you create full-screen images from each of the slides of a Google Docs presentation without too much manual work? For the previous blog post on my Munin keynote, I wanted to include some pictures from my 90-slide presentation. There is probably a point and click solution to this problem, but it is even more fun to use some command line tools to help out. These commands have been tested on Ubuntu 19....

November 29, 2019 · 1 min · 191 words · ARJ

Keynote: Experimenting with Open Research Experiments

Yesterday I gave a keynote lecture at the Munin Conference on Scholarly Publishing in Tromsø. This is an annual conference that gathers librarians, research administrators and publishers, but also some researchers and students. It is my first time to the conference, and found it to be a very diverse, interesting and welcoming group of people. Abstract Is it possible to do experimental music research completely openly? And what can we gain by opening up the research process from beginning to end?...

November 29, 2019 · 5 min · 999 words · ARJ