Rockbox has many strong features! However, up to now I could find none for editing sound files. I would find it comfortable to cut files I am listening to. E.g. recordings often need to be cut at the beginning and the end. With an editing feature in rockbox this could be done on the fly without turning on a much bigger computer. One could think about the setting of two markers and the copying of this section into a file which receives the original name together with a numbering.