I realize this is for Mac OS 10.4 or higher, so where is 10.4 or lower???
So Audacity downloaded OK. Also downloaded FFMPEG. Did the manual search for the file FFMPEG…avformat-*.dylib. What I found was …libavformat.dylib. Same?? Hit Open, OK,OK.
Download a karaoke Youtube video in MP4 format with 4k Video Downloader and with Activate 4k Video Downloader.
Each time a drag either one of those files I get error message (attachment).
MacOS Catalina Version 10.15.7, Intel Corei5