Normalize audio, then reduce the volume in ffmpeg -

I have a question related to ffmpeg. First of all, this is the scenario, I am working on a project where I presented an audio Need to do and then maybe some background music. I also need to make the audio normal. I

For generalization, I use anything similar to this post:

In short, let me Volume adjustment is given, which I apply to ffmpeg again:

  ffmpeg -i & lt; Input & gt; -f "volume = xxxdB" & lt; Output & gt;  

So far it is so good. Now we consider the backing track, it does not want to be equal volume of speakers, it will actually get distracted, so I am doing a few percent Want to I can do it with FFPAAG, I can do this (quantity can be set up to 50% by example):

  ffmpeg -i  

By using these two commands back, I may get the desired result.

My question has two parts:

1. Is there a way to do this in one step?
2. Is there any benefit to do this in one step?

Thanks for any help!

After doing some more tests, I really think the answer was very straight forward, There was a need to

ffmpeg-i & lt; Input & gt; -f "volume = xxxdB, quantity = 0.5" & lt; Output & gt;

I took a while to realize this, before I feel confident.