....or something like that.

What I did:

1) I converted all my CD in .APE format.
2) I applied ReplayGain values to the .APE files...
3) than I converted all to MP4 using Foobar

Now I'm considering that, listening the files on my nano, the value applied is a bit too low.
I would like to change it.

Is it possible to do this directly on the MP4 files? Using again Foobar?
Or I need to apply a new ReplayGain value on the .APE files and than convert everything again in Mp4?

Or, I listen too low, simply because the nano limits the volume and no replaygain value is stored on the mp4 files and/or the nano does not manage replaygain values?

I do not remember......someone could clarify these aspects?

Thanks

I recently encountered a similar situation - I have my CD collection archived in flac and converted to AAC files with foobar 0.9.5.1 and Nero AAC 8/07 release to put on my ipod touch.

After investigating the various ways of doing it, I concluded the cleanest way is to utilize Apple's SoundCheck. The mathematical conversion between ReplayGain levels to SoundCheck has been worked out already.

1. When using the foobar 0.9.5.1 converter, I checked "ReplayGain-scan output files as albums" - which will scan and insert the four ReplayGain metadata tags in the output files.
2. mp3tag 2.40 has a very nifty function rg2sc that converts ReplayGain to SoundCheck. You can take advantage of writing a simple little action to batch convert files. First add all the files you wish to add SoundCheck tags to the main mp3tag window and select the files.

Under Convert, Actions make a New Action Group. In this Action Group, you will make the following two Format Value actions.

Field: COMMENT ITUNENORM

Format String: $if($eql(%_extension%,mp3),$rg2sc(%REPLAYGAIN_ALBUM_GAIN%),)

Field: ITUNNORM

Format String: $if($eql(%_extension%,m4a|mp4),$rg2sc(%REPLAYGAIN_ALBUM_GAIN%),)

2a. You can change the REPLAYGAIN_ALBUM_GAIN to REPLAYGAIN_TRACK_GAIN if you prefer ReplayGain Track Gain instead. This will most closely mimic SoundCheck's performance. Also note the the SoundCheck tag is different for mp3 files and AAC files.
2b. I have found that insuring your metadata tags are as complete and accurate as possible is a good step at this point and mp3tag makes this very easy.
3. Start iTunes and enable SoundCheck in Edit, Preferences, Playback, and also on your ipod. iTunes will insist on converting your existing library (canceling the operation will only have try to scan every time it starts), so you may wish to trim your library before turning this on in iTunes or use foobar and mp3tag on your current library before turning on SoundCheck.
4. Import your newly minted mp4 files into iTunes. iTunes is smart enough to see the SoundCheck tag in the imported files and not rescan them.

These mp3 and AAC files have the advantage of having both ReplayGain and SoundCheck data in them, allowing the optimal playback based on whatever player you use.

Good luck!
Bing

Try AAC Gain.

It uses the same Gui as mp3gain but works on aac files.

I think I found it on Rarewares but you could google it.

I use iGain, which integrates with iTunes and works with mp3s and both Apple and Nero AAC.