How to modify functionality (skip song, play, pause) with side phone volume keys?

Question

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:

1. Do it with Tasker
2. Download an app to achieve this (not a media player)
3. Develop an app to achieve this (any advice?)
4. 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.

Answer 1

PowerAmp is an open source app, which may serve as a good starting point for developing your own app. The code can be found here.

Answer 2

Headset button controller is an excellent app in market which will do all these functions..

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