How to modify functionality (skip song, play, pause) with side phone volume keys? This is a really requested feature in a lot of forum, but I haven't found any convincing solution.

I'd like that my volume keys:


If simple (short) press both together, pause/play.
If simple (short) press of single key, change the volume up or down.
If pressed and hold change track forward or backward.


My options in order from preferred to less preferred are:


Do it with Tasker
Download an app to achieve this (not a media player)
Develop an app to achieve this (any advice?)
Download a media player that has mentioned functionality.


Thanks, Diego

Note: With volume keys I don't mean keys in the headphone, I mean those which are at the side of the phone.
Headset button controller is an excellent app in market which will do all these functions..

https://market.android.com/details?id=com.kober.headsetbutton&amp;feature=more_from_developer