I've got a bunch of MP4/AAC files that I just got while at my sister's place. She has a mac, and I used iTunes v6 to rip them. To transport them home I loaded them up on my rio mp3 player, which works as a generic mass storage drive and I have used perfectly fine for this sort of transfer before.

Well, something bad happened at some stage of the process, and most of the files have a corrupt frame in the AAC stream. Stupid macs... They play fine up till the end of the file, then produce errors. I'd like to fix them because a) foobar pops up the warning box every time, though I suppose I could turn that off; and b) I can't replaygain them.

The thing is, the bad frames are all at or very near the end of the file. So one option might be to cut the files with some sort of tool that could take off the last few seconds and thus get rid of the bad frame. Are there any AAC cutters like there are for mp3? And do any of them have the kind of interface that can take cue sheets or something else like that so I can automate the process and not have to do 90 files by hand?

...
For the files that have problems, an example Foobar report:

and VLC report:

Or, in my dreams, might I wish for a tool that could automatically repair this kind of error?

Well, no replies... But I found mp4box and Yamb, so I've been manually splitting the files. Tedious, but worth it.

Lucky for me none of the six affected albums are gapless. So far I haven't seen any of them cut off before the song was clearly over. I just wonder what made the dumb mac corrupt the files in the first place. I figured out that all files I copied by dragging the files themselves were fine, and the damaged ones I dragged directories. Why that would change things, who knows.

There is no difference in the way files are copied between platforms. If the files work properly on the Mac (or Unix workstation or PC or mainframe or wherever they originated) and changed when you copied them to an external, I'd blame the external device before you blame the platform. Platform zealotry isn't appreciated here, and calling Macintosh or any other platform "dumb" really doesn't impress anyone around here.

A quick search on Google shows countless posts and complaints on other sites and forums of files being corrupted when using Rio players as mass storage devices. The most suggested fix is to ensure that the DAP has the latest firmware update. There are also posts about misbehaving Rio players that still don't work correctly after updating (and even after removing all the tracks with the Rio Music Manager), but do work correctly after being reformatted. I also see that Rio offers plugins for iTunes on OS X to directly support the Rio.

It seems that support for the Rio has been discontinued and the devices will no longer made. However, models purchased under warranty are still supported and all models currently sold will still be covered. Firmware and driver updates are available from http://www.digitalnetworksna.com/support/rio/.

It is also possible that the files were corrupted before you copied them. Did you try them on your sisters machine? Maybe she has some system problems there?

Anyway, for a MP4/AAC cutting and splicing, you don't need any other software if you are using OS X, as QuickTime can do this task out of the box (and without re-encoding the streams). The full QT API is also supported via osascripting meaning you can build batch tools to very easily with the command line. QT Pro supplies a full GUI for most functions.

You only need external tools (rather than QT as of 7.1.2) if you are editing multichannel AAC audio - >2 channels is supported for editing in an MOV container, but not an MPEG-4 container right now.