It uses ffprobe under the hood and can output an xml file. Here's an example output.svg:
(Although it is slow - almost as slow as transcoding, because it scans the whole video.)
I've put together a Python script that will do all of this.
Generates the ffprobe and ffmpeg commands and runs them And outputs a file without black clips
GitHub gist: https://gist.github.com/FarisHijazi/eff7a7979440faa84a63657e085ec504
Use ffprobe to extract black frames and ffmpeg to trim them and ...