Alter audio without re-encoding video

[umbala]

I have thousands of short video clips (5 seconds to 30 seconds) that have the sound either too low or to loud. I'm looking for a way to alter the audio (make it louder or quieter or silent) directly in one step. I'm trying to avoid having to extract the audio from each file, then modify it, then remux it with the video.

Are there any tools that can do this in one step? I've tried a few, but none of them can do what I'm trying to achieve. I would be happy with a command line tool even if it takes multiple steps if I could script it or automate it in some way. All my files are using .mp4 container, mpeg4 video (h264), and AAC audio.

If anyone has any suggestions it would be greatly appreciated.

[Cornucopia]

In 1 step, no.

You already mentioned 3 different things that need to be done.

Scott

[netmask56]

If they were in mkv containers then you could use PopCorn MKV AudioConverter using the 'Simple AudioConversion' tool (found under menu item FILE) to normalise all tracks. Does it in situ and doesn't touch the video. Otherwise as Cornucopia says succinctly - No