Hello. Thank you for your recommendation. apparently I installed it correctly, but it doesn't recognize it in the system. It marks several routes:
# ffmpeg
ffmpeg version N-53917-g5ff2ff6bd9-static https://johnvansickle.com/ffmpeg/ Copyright (c) 2000-2020 the FFmpeg developers
built with gcc 8 (Debian 8.3.0-6)