Kayak motion analysis with video-based horizon leveling

Last year, I wrote about video-based motion analysis of kayaking. Those videos were recorded with a GoPro Hero 8 and I tested some of the video visualization methods of the Musical Gestures Toolbox for Python. This summer I am testing out some 360 cameras for my upcoming AMBIENT project. I thought I should take one of these, a GoPro Max, out for some kayaking in the Oslo fjord. Here are some impressions of the trip (and recording)....

July 13, 2022 · 3 min · 590 words · ARJ

Removing audio hum using a highpass filter in FFmpeg

Today, I recorded Sound Action 194 - Rolling Dice as part of my year-long sound action project. The idea has been to do as little processing as possible to the recordings. That is because I want to capture sounds and actions as naturally as possible. The recorded files will also serve as source material for both scientific and artistic explorations later. For that reason, I only trim the recordings non-destructively using FFmpeg....

July 13, 2022 · 2 min · 303 words · ARJ

Export images from a PDF file

I have previously written about how to export each of the pages of a PDF file as an image. That works well for, for example, presentation slides that should go on a web page. But sometimes there is a need to export only the images within a page. This can be achieved with a small command line tool called pdfimages. One way of using it is: pdfimages -p -png file.pdf image This will export all images in file....

June 16, 2022 · 1 min · 135 words · ARJ

Adding subtitles to videos

In my ever-growing collection of FFmpeg-related blog posts, I will today show how to add subtitles to videos. These tricks are based on the need to create a captioned version of a video I made to introduce the Workshop on NIME Archiving for the 2022 edition of the International Conference on New Interfaces for Musical Expression (NIME). This is the video I discuss in this blog post: Note that YouTube supports turning on and off the subtitles (CC button)....

June 11, 2022 · 6 min · 1193 words · ARJ

Em-dash is not a hyphen

I have been doing quite a lot of manuscript editing recently and realize that many people—including academics—don’t understand the differences between the symbols hyphen, en-dash, and em-dash. So here is a quick explanation: hyphen (-): is used to join words (“music-related”). You type this character with the Minus key on the keyboard, so it is the easiest one to use. en-dash (–): is used to explain relationships between two concepts (“action–couplings”) or in number series (0–100)....

May 13, 2022 · 2 min · 327 words · ARJ

Sound Design vs Sonic Design

What is the difference between “sound design” and “sonic design”? This is one of the many questions I have pondered while preparing the International Seminar on Sonic Design the last half year. My idea with using the term “sonic design” for the seminar was inspired by Professor Rolf Inge Godøy, my former supervisor, mentor, colleague and friend, to whom the seminar was dedicated. With his background in music performance and composition, he always talked about how musicians and composers “shape” sound through their practice....

May 10, 2022 · 1 min · 201 words · ARJ

Running a disputation on YouTube

Last week, Ulf Holbrook defended his dissertation at RITMO. I was in charge of streaming the disputation, and here are some reflections on the technical setup and streaming. Zoom Webinars vs YouTube Streaming I have previously written about running a hybrid disputation using a Zoom webinar. We have used variations of that setup also for other events. For example, last year, we ran RPPW as a hybrid conference. There are some benefits of using Zoom, particularly when having many presenters....

May 7, 2022 · 5 min · 958 words · ARJ

Programmatically resizing a folder of images

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)....

April 13, 2022 · 1 min · 162 words · ARJ

Merge multiple MP4 files

I have been doing several long recordings with GoPro cameras recently. The cameras automatically split the recordings into 4GB files, which leaves me with a myriad of files to work with. I have therefore made a script to help with the pre-processing of the files. This is somewhat similar to the script I made to convert MXF files to MP4, but with better handling of the temp file for storing information about the files to merge:...

March 31, 2022 · 1 min · 168 words · ARJ

Digital competency

What are the digital competencies needed in the future? Our head of department has challenged me to talk about this topic at an internal seminar today. Here is a summary of what I said. Competencies vs skills First, I think it is crucial to separate competencies from skills. The latter relates to how you do something. There has been much focus on teaching skills, mainly teaching people how to use various software or hardware....

March 7, 2022 · 6 min · 1186 words · ARJ