Normalize Audio level for different sources

[Lele-brz]

Hi,
I was wondering if there's a way to normalize the volume when encoding, this in order to have same audio level even from different sources.
In my case I'd need to use AAC, is there any command line software that can do that?

thanks in advance
bye

[fibbingbear]

I believe there's a tool called AACGain. I have not used it, but I have used MP3Gain, which is what AACGain is based off.

At least for MP3Gain, and you can specify that every file be normalized to the same volume level. It has the nice feature that the volume changes are recorded in comments in the file, as opposed to actually changing the audio data (I guess the music players look at these comments to determine volume, because as far as I can tell it's worked on all my devices), so you can remove the normalization later without have to re-encode.

Note that on the mp3gain web site, they mention (as of 2005) that the AAC support is still experimental, and record backing up the files before applying normalization (I guess in case of accidental corruption?)