I use ffmpeg to:
- add multiple audio into a video file and offset them
- discard original audio in the video
Everything is OK except that
1. the audio volume in the
result.mp4 is remarkably lower than the volumes in each individual input audio
2. sound quality in
mp3(which is a background music) also drops
I listened to each
3gp and the
mp3 files, can confirm that the two issues above.
Why is this happening?
ffmpeg -i 1.mp4 -i 1.3gp -i 2.3gp -i 1.mp3 -filter_complex "adelay=10000|10000[s2];[3:a][1:a][s2]amix=3[a]" -map 0:v -map "[a]" -c:v copy result.mp4