FFmpeg Permission Denied: Fix Cannot Read Input or Write Output on Linux, macOS, Windows, Docker
Fix the FFmpeg 'permission denied' error by separating input-read from output-write failures, with solutions for Linux, macOS, Windows, and Docker: checking permissions with ls -l / ls -ld, chmod, writing to a writable directory, the Docker --user flag, and Windows file locks.
June 8, 2026
