I'm trying to add guitar tabs to a music video, do you know any software to do it?
Try to break your task into elementary blocks. If you can't solve the problem, break it into even smaller blocks.

Tabs? If which format? Maybe in form of MIDI files? Or even text on papers? Or in some form of txt files? It is a very important question. In some cases you must convert your tabs from one format to another.

What do you want add to the video? You can add only sequences of images or sounds, not "guitar tabs". You need draw some images first. For example, images with the fretboard and white circles on it.

If I had such a task, I would first convert the tabs into a form convenient for me. Then I would write a simple program that would draw pictures. This can be a C program, a Python script, or a script for 3ds max. Then I can use ffmpeg to assemble such images. And, as final task, I will use some software like Premiere or Final Cut to compose and sync my images with video.