Reverse playback

[MazingerZ]

I think this would be great to detect mackmasking messages!

[saratoga]

This will never happen because:

1)  You can't really flip around the direction of most lossy codecs without first decoding them to PCM.
2)  Even if you could you'd have to write an entirely new decoder for each format

So basically this is something that has to be done on a PC using a sound editor.