It depends on the problems with it. Various video (and audio) filters are designed for correction and improvement: Color Grading, Brightness, Contrast, White Balance, Hue/Lightness/Saturation, Crop, Lens Correction, Reduce Noise, Sharpen, and Stabilize. Also, you might want to remove interlacing and you can export as progressive and control the quality of that (Deinterlacer). After cleaning, you might want to use a very high quality scaler to increase resolution because maybe you will use it a (U)HD project and the other tool does scale as well. In that case, in Export you can set the Interpolation to Lanczos.
Made a small demo using some color clips to show you a few simple and some more complex transitions and effects you can use with Shotcut. Take a look at the filters to see how they are applied. Hope this will help with any future projects you might have.
Slideshow.mlt (26.1 KB)
THanks for answering! i really appreciate it! 
Sorry for a stupid question - I just downloaded Shotcut and started using it tonight. In the video above (in this thread) - there are blue hearts moving across a black background layer. Can anyone tell me how to create this? Or is it a preset in Shotcut that I can choose from for a background? Thanks for any help!
It’s not a preset.
You need 2 video tracks. Background on the lower track animated with size and position filter. The video on the upper track sized with the size and position filter or the rotate and scale filter to allow the background through.
Music scroll.zip (3.3 MB)
Background is a still image scrolling with S and P filter. Video sized and positioned with S and P.
Topaz Labs is the most well-known company that makes A.I. upscaling solutions for photos and video. They have a video upscaler that uses subtle A.I. technology to add details and sharpness to old or low resolution footage. I’ve watched a bunch of videos on Youtube of people using the software, and there are mixed results. It can’t invent magical details that have too few pixels to work with, but it can produce better results than standard resampling algorithms in many cases.
Corridor Crew made a funny video recently that shows what is possible and what is not possible with such technologies.
Unfortunately Topaz products are not overly cheap, a little out of my price range. I’ve tried some of their free trials in the past, and my perfectionist expectations were disappointed. Again, the software can’t work miracles.
Linus Tech Tips also made a video about the software:
Oh weird, just noticed this post was from 2018! Ha. No idea why it got to the top of the forum again!