When working with various types of video analysis, I often end up with video files without audio. So I need to add the audio track by copying either from the source video file or from a separate audio file. There are many ways of doing this. Many people would probably reach for a video editor, but the problem is that you would most likely end up recompressing both the audio and video file....
Many people have asked me about what types of microphones to use for streaming and recording. This is really a jungle, with lots of devices and things to think about. I have written some blog posts about such things previously, such as tips for doing Skype job interviews, testing simple camera/mic solutions, running a Hybrid Disputation, and how to work with plug-in-power microphones. Earlier today I held a short presentation about microphones at RITMO....
Yesterday, PhD fellow Mojtaba Karbassi presented his research on impedance control in robotic drumming at RITMO. I will surely get back to discussing more of his research later. Today, I wanted to share the analysis of one of the videos he showed. Mojtaba is working on developing a robot that can play a double stroke drum roll. To explain what this is, he showed this video he had found online, made by John Wooton:...
In my ever-growing collection of smart FFmpeg tricks, here is a way of converting from one container format to another. Here I will convert from a QuickTime (.mov) file to a standard MPEG-4 (.mp4), but the recipe should work between other formats too. If you came here to just see the solution, here you go: ffmpeg -i infile.mov -acodec copy -vcodec copy outfile.mp4 In the following I will explain everything in a little more detail....
I take a lot of timelapse shots with a GoPro camera. Usually, I do this with the camera’s photo setting instead of the video setting. That is because I find it easier to delete unwanted pictures from the series that way. It also simplifies selecting individual photos when I want that. But then I need a way to create a timelapse video from the photos easily. Here is an FFmpeg one-liner that does the job:...
I am happy to announce that Agata Zelechowska yesterday successfully defended her PhD dissertation during a public disputation. The dissertation is titled Irresistible Movement: The Role of Musical Sound, Individual Differences and Listening Context in Movement Responses to Music and has been carried out as part of my MICRO project at RITMO. The dissertation is composed of five papers and an extended introduction. The abstract reads: This dissertation examines the phenomenon of spontaneous movement responses to music....
FFmpeg is a fantastic resource for doing all sorts of video manipulations from the terminal. However, it has a lot of features, and it is not always easy to understand what they all mean. I was interested in understanding more about how the tblend function works. This is a function that blends successive frames in 30 different ways. To get a visual understanding of how the different operations work, I decided to try them all out on the same video file....
This is primarily a note to self post, but could hopefully also be useful for others. At least, I spent a little too long to figure out to embed a YouTube video with a specific language on the subtitles. The starting point is that I had this project video that I wanted to embed on a project website: However, then I found that you can add info about the specific language you want to use by adding this snippet after the URL:...
Continuing my explorations of FFmpeg for video visualization, today I came across this very nice blog post on creating “pixel array” images of videos. Here the idea is to reduce every single frame into only one pixel, and to plot this next to each other on a line. Of course, I wanted to try this out myself. I find that creating motiongrams or videograms is a good way to visualize the content of videos....
{width=“300”} This is a note to self, and could potentially also be useful to others in need of converting “old-school” MPEG-2 files into more modern MPEG-4 files using FFmpeg. In the fourMs lab we have a bunch of Canon XF105 video cameras that record .MXF files with MPEG-2 compression. This is not a very useful format for other things we are doing, so I often have to recompress them to something else....