add audio to a video ffmpeg code example

Example 1: ffmpeg combine audio and video

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

Example 2: ffmpeg add audio to video at specific time

ffmpeg -y -i a.mp4 -itsoffset 00:00:30 -i sng.m4a -map 0:0 -map 1:0 -c:v copy -preset ultrafast -async 1 out.mp4