avconv change volume of an audio file

Question

我想更改第二个音频文件的音量，但到目前为止，我尝试的所有操作均不起作用。

avconv -i input1.mp3 -i input2.mp3 -aq 1 -filter_complex amix=inputs=2:duration=first:dropout_transition=2 output.mp3

Answer 1

This is using FFmpeg, but I suspect it would be similar for avconv. All I did was adapt this answer until it seemed to have the desired effect on my test files.

Test files

ffmpeg -f lavfi -i "anoisesrc=d=20:c=brown:r=44100:a=0.5" -q:a 1 input1.mp3
ffmpeg -f lavfi -i "sine=frequency=1000:duration=20" -q:a 1 input2.mp3

No attenuation

ffmpeg -i input1.mp3 -i input2.mp3 -filter_complex \
"[0:a]volume=1.0:precision=fixed[a0]; \
 [1:a]volume=1.0:precision=fixed[a1]; \
 [a0][a1]amix=inputs=2:dropout_transition=2" -q:a 1 output1.mp3

50% attenuation of the first input file

ffmpeg -i input1.mp3 -i input2.mp3 -filter_complex \
"[0:a]volume=1.0:precision=fixed[a0]; \
 [1:a]volume=0.5:precision=fixed[a1]; \
 [a0][a1]amix=inputs=2:dropout_transition=2" -q:a 1 output2.mp3

50% attenuation of the second input file

ffmpeg -i input1.mp3 -i input2.mp3 -filter_complex \
"[0:a]volume=0.5:precision=fixed[a0]; \
 [1:a]volume=1.0:precision=fixed[a1]; \
 [a0][a1]amix=inputs=2:dropout_transition=2" -q:a 1 output3.mp3