I have two below command that is works perfectly for this question but how to work with one command?
Commands:
ffmpeg -i video.mp4 -i audio.mp3 -filter_complex \
"[0:a][1:a]amerge=inputs=2[a]" \
-map 0:v -map "[a]" -c:v copy -c:a libvorbis -ac 2 -shortest output.mp4
ffmpeg -i audio.mp3 -af "volume=150:enable='between(t,10,20)'" audiochange.mp3
Thanks in advance.