Many image file formats exist, but which ones are better for what task? Here is a quick overview in my little series of PhD advice blog posts (the previous being tips on dissertation writing and the public PhD defense). Two different image types When choosing a file format for your image, the first thing is to figure out whether you are dealing with a raster image (photos) or a vector image (line illustrations).

I came across an interesting blog post by Alex Chen on how to write better image descriptions for web pages. They propose an “object-action-context” approach when writing image descriptions. I see that such an approach could also be helpful for my sound actions project. Adding better descriptions I am soon getting to the end of my year-long project of recording one sound action daily. A sound action is a multimodal entity consisting of body motion and its resultant sound.

As mentioned yesterday, the source files for the illustrations in my Sound Actions book are available on GitHub in the form of LibreOffice Draw files (ODG). Draw may be less powerful but much easier to work with than more advanced line art software, such as Inkscape. One of the nice things about the LibreOffice package is its scripting possibilities. While working on my book, I wrote a shell script that would read all the ODG files in a folder and convert them to PDF and PNG files:

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.

I often have to convert between different resolutions of videos and images and always forget the pixel dimensions that correspond to a 16:9 format. So here is a cheat-sheet: **2160p: **3840×2160 **1440p: **2560×1440 **1080p: **1920×1080 **720p: **1280×720 540p: 960x540 **480p: **854×480 **360p: **640×360 **240p: **426×240 120p: 213x120 I also came across this complete list of true 16:9 resolution combinations, but the ones above suffice for my usage. Happy converting!

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: