How to manage volume using FFMPEG -

is there way set/modify/change/update volume of audio when playing using ffmpeg library. in advance.

you can use ffmpeg's volume filter. you'll want search around figure out how ffmpeg filters working in application, it's worth effort.

you can manually multiplying pcm data in decoded audio data (avframe->data[0]) volume multiplier (>1.0 increase volume, <1.0 decrease volume), you'd need know format of decoded data.