Adjust volume of both input mp3 files while merging using ffmpeg

Question

I am using the following command to merge two audio files (mp3) into one output.mp3

-i /sdcard/NNR/input1.mp3 -i /sdcard/NNR/input2.mp3 
    -filter_complex amer         


        

Answer 1

You would use

-i /sdcard/NNR/input1.mp3 -i /sdcard/NNR/input2.mp3
-filter_complex "[0]volume=0.5,pan=2c[a];[1]volume=0.7,pan=2c[b];[a][b]amix=duration=shortest"
-ac 2 -c:a libmp3lame -q:a 4 /sdcard/NNR/output.mp3