Ffmpeg

I have previously written about how it is possible to “flatten” a Ricoh Theta+ recording using FFmpeg. Now, I have spent some time exploring how to process some recordings from a Garmin VIRB camera. Some hours of recordings The starting point was a bunch of recordings from our recent MusicLab Copenhagen featuring the amazing Danish String Quartet. A team of RITMO researchers went to Copenhagen and captured the quartet in both rehearsal and performance....

Typical video files, such as MP4 files with H.264 compression, are usually small in size and with high visual quality. Such files are suitable for visual inspection but do not work well for video analysis. In most cases, computer vision software prefers to work with raw data or other compression formats. The Musical Gestures Toolbox for Matlab works best with these file types: Video: use.jpg (Motion.jpg) as the compression format. This compresses each frame individually....

Here is another FFmpeg-related blog post, this time to explain how to rotate a video using the command-line tool FFmpeg. There are two ways of doing this, and I will explain both in the following. Rotation in metadata The best first try could be to make the rotation by only modifying the metadata in the file. This does not work for all file types, but should work for some (including ....

I have previously written about how to trim video files with FFmpeg. It is also easy to crop a video file. Here is a short how-to guide for myself and others. Cropping is not the same as trimming This may be basic, but I often see the concepts of cropping and trimming used interchangeably. So, to clarify, trimming a video file means making it shorter by removing frames in the beginning and/or end....

Sometimes, there is a need to convert an audio file into a blank video file with an audio track. This can be useful if you are on a system that does not have a dedicated audio player but a video player (yes, rare, but I work with odd technologies…). Here is a quick recipe FFmpeg to the rescue When it comes to converting from one media format to another, I always turn to FFmpeg....

We are organizing the Rhythm Production and Perception Workshop at RITMO next week. As mentioned in another blog post, we have asked presenters to send us pre-recorded videos. They are all available on the workshop page. During the workshop, we will play sets of videos in sequence. When doing a test run today, we discovered that the sound levels differed wildly between files. There is clearly the need for normalizing the sound levels to create a good listener experience....

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....

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....

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:...