4:3 to 16:9 Infill

I’ve been in text generation for a while, but I want to mess about with video. I have some old 4:3 videos that I want to upscale. I suspect Topaz would be a good way to go, but I also want to infill to stretch them to 16:9. 1. How would I best go about fine-tuning a video model with the current corpus of 4:3 video to infill the space? 2. What base model should I use? 3. Is there a model I should be using to do my upscaling? 4. Is there a tool that can do all of the above and I just missed it?