Open-source is more than just free software, it is an entirely new universe full of powerful tools designed and maintained by thousands of people around the world to solve all kinds of problems. Today, I will share with you the most useful ones for video design, covering visual design, video making and VJing. Order is random.
The first step before you make your own VJ loops and DJ visuals is to create a good starting concept; Krita is the program for such a task. This open-source software gives you all the necessary art tools for designing your concept art from scratch and not to die in the attempt.
Let's talk about GIMP, a very complete raster graphics and photo editing application that allows you to manipulate your images professionally and prepare them for your VJ loops. Through a wide range of plugins and scripts, you can correct color, apply filters, create animations, extract frames from video, save different codecs, save for web and much more. Is it intuitive? Yes. Is it all-in-one? Not really, you will need to search and install some plugins in order to do things like exporting .exr files or opening video files; nevertheless, there is clear and good documentation available. It runs on GNU/Linux, OS X, and Microsoft Windows. Last but not least, there is an extension in Blender that allows interoperability with GIMP .xcf or .xjt files.
How can you handle vector graphics instead of raster graphics? Inkscape is the answer. If you have ever used Illustrator, tools and interface will be very familiar to you. It includes precision, path and text tools, 3D extensions, filters, great pattern generators and more. Save as .svg or .eps and get ready to use your DJ logo vector path in any 3D or motion graphics software. It is available for Linux, Windows and Mac OS X (requires XQuartz). Either you just want to manipulate paths or create something more complex, Inkscape is a robust and professional software option at no cost. Another fresh and multi-platform alternative is Gravit Designer.
Do you really need to buy that expensive 3D application? Blender includes potent 3D modeling and texturing tools, an efficient photorealistic render engine, a real-time render engine called EEVEE, a node-based editor for materials, dynamics, awesome animation workflows to create your VJ loops, a compositor, a video editor and motion graphics addons. It is not as intuitive as Cinema 4D, but it is worth learning and there is a lot of documentation out there. If you do not find the way to do something in Blender, do not worry, somewhere in the world one skillful developer has created a plugin and it is available for everyone.
Now that you have your image sequences, you will need to put all together and add some effects. If you do not have After Effects, there is an open-source compositing software called Natron. It is a cross-platform node-based tool, the UI is very similar to Nuke and you have access to a variety of effects, including motion blur and color correction effects. This open-source project is currently stopped and looking for a new maintainer.
Ok, but you are a VJ, so you are going to need a video mixing tool. There are several open-source options out there, but to get started you can try GLMixer; it is one of the best (and maybe the most updated open-source VJ software project). This VJ application allows you to import and mix VJ loops, DJ visuals, videos, image files, vector graphics, algorithmic patterns and GPU plugins with endless possibilities (FreeFrame and Shadertoy). It includes an interesting circle UI for handling different files at the same time in a practical way. It works on Linux, OSX, and Windows. For further information, check out the video tutorial Quick Tips for Getting Started in GLMixer Free VJ Software. For video mapping projects you may prefer MapMap.
ShareX is an incredible and complete screencast software. This kind of tool is essential for any productive workflow, either you want to share screenshots or record VJing tutorials. At no cost, you can capture specific regions, create GIFs or HD videos, benefit from constant updates and much more. It is only available for Microsoft Windows; you could consider using Dahu for Linux and Mac.
Even if you can do video editing with Blender, sometimes you simply do not need all those extra tools for 3D Design and Animation. So, if your main focus is video editing, the OpenShot Video Editor is the best option for you. You can add simple video transitions, some basic effects and keyframes to your tracks. You can also create titles, however, this tool needs Blender to be installed to work. In a few words, OpenShot is a clean, fast and free video editor for simple projects. You can also try Shotcut, it is another interesting open source and free video editor alternative.