I'm trying to correct some volume issues on a couple movies. some of my movies have audio from 5.1 surround playing from stereo speakers, causing the volume to be really quiet for dialog and loud for action scenes and such.
I have found a ffmpeg command to correct this with dynamic range compression:
ffmpeg -i my_movie_with_bad_volume.mp4 -af dynaudnorm -vcodec copy output.mp4
This corrects the audio, but what i would like to do, instead of the output file having only the adjusted audio, i'd like to have the audio as a second track i can select. this way i still have the original audio available as an option, in the same video file.
Is this possible to modify the command line to do this?