merge video with another audio ffmpeg code example

Example 1: ffmpeg add two videos together

$ cat mylist.txt
file '/path/to/file1'
file '/path/to/file2'
file '/path/to/file3'
    
$ ffmpeg -f concat -safe 0 -i mylist.txt -c copy output.mp4

Example 2: ffmpeg combine audio and video

ffmpeg -i video.mp4 -i audio.wav -c:v copy -c:a aac output.mp4