FFmpeg notes (including FFmpeg install): https://www.rickmakes.com/ffmpeg-notes/
FFmpeg playlist: https://www.youtube.com/playlist?list=PLErU2HjQZ_ZOPDZ71Khzt5PX4X4j6flkg
View Video Settings
ffprobe video_without_audio.mp4
Add Silence to Video File
ffmpeg -i video_without_audio.mp4 -f lavfi -i anullsrc -vcodec copy -acodec aac -shortest video_with_silence.mp4