I've used this code for merging three videos together with ffmpeg :
ffmpeg -y -f concat -safe 0 -i list.txt -c copy done.mp4
the list.txt contains :
file 'first.mp4' duration 2.5 file 'second.mp4' duration 20.0 file 'third.mp4' duration 1.5
But the output video doesn't have any sound! I want sound of each one remains on the output.
what code should i use?