How to add GIF to a static background (PIL + imageio) V.2 – The Better One

My previous version has flaws. It works well for opaque GIFs, but OpenCV is famous for not being good with transparent images. So instead of OpenCV I use imageio for GIF iteration and PIL for adding GIF frames to the static background.

Why do more?

The original algorithm left these artifacts, look at the cyan block on the intersection of GIF frame and a darker abstract part:

The artefact in question
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Video Generation Journey. Part 1: Making frames (problems 1-4)

Initially, I aimed to make one big post, but I am splitting it up. This Part 1 is about how I made the frames to generate videos from.

Intro

I have been on and off doing this project for a few months. Many things did not work for me – from ffmpeg to sheer OpenCV/ffmpeg installation on Apple M1 systems – and I am not 100% sure what made it work to this day. I plan to put myself in a situation where I have to do it again, and I will make a guide then. However, right now, I can only say that this video tutorial on running native ffmpeg and this guide from OpenCV themselves are good places to start.

The last time I used OpenCV was in 2017 when I worked on my graduate work. Back then, I processed prerecorded videos with no need to worry about audio. So I had some background prior to this project, but I was in no way ready for the ride.

Buckle up!

Table of contents

  • What do I have to create?
  • Limitations
    • Background
    • Phrases
    • Audio
  • Problems
    • Problem 1: GIF on a background
    • Problem 2: Putting text on the image
    • Problem 3: Text wrapping
    • Problem 4: Text blocks positioning
  • Results so far
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ffmpeg: Non-monotonous DTS in output stream 0:0 – Video Generation Series (Part 2) [ERROR]

This error occured when I used ffmpeg to concatenate different videos that I generated:

ffmpeg -f concat -safe 0 -i list.txt -c copy final_video.avi -y
BTW, if you want to run ffmpeg or any other command inside a python script (a very reasonable idea), use subprocess:

command = "ffmpeg -f concat -safe 0 -i list.txt -c copy final_video.avi -y"
subprocess.Popen(command.split(), stdout=subprocess.PIPE)

As a result – the videos got smashed together – some frames even never appeared.

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