FFmpeg Useful Commands

$ ffmpeg -i video.mp4 -i audio.m4a -c:v copy -c:a copy output.mp4

$ ffmpeg -i videoplayback.webm -i videoplayback.m4a -c:v copy -c:a copy output.mkv

$ ffmpeg -i output.mp4 -ss 0 -t 60 first-60-sec.mp4

$ ffmpeg -i video.mp4 -i audio.mp3 -c:v copy -c:a aac -strict experimental -map 0:v:0 -map 1:a:0 output.mp4

$ cat concat.txt
file '/path/to/video1.mp4'
file '/path/to/video2.mp4'
file '/path/to/video3.mp4'

$ ffmpeg -f concat -i concat.txt -c copy output.mp4