Sry but is there any online tools to do this? We all know there are a lot of online sites to download Youtube videos, but seems no such feature?
Most sites, like mine use youtube-dl which just gets the video source file.
To crop it and process it at scale you are talking about thousands of dollars of servers to first download the file then process it.
Would be cool to see something client side using ffmpeg in browser, like https://github.com/ffmpegwasm/ffmpeg.wasm
Found a previous post from someone using that lib https://news.ycombinator.com/item?id=26580333