1) it is NOT encrypted code. you are allowed to modify it as much as you want, but not to distribute it in any way.
2) 100% open source. remember: open source has nothing to do with "payment". that means, as I said before, you can access all the source code from the component and modify whatever you want, but only you can use it.

it is easy to write modules for MC. I have writen some, and I'm preparing some others. "top downloads" is not under development right now, but maybe soon. you may want to take a look at this post

http://www.joomlamusicsolutions.com/en/forum/suggestions/most-lstened-top-rated.html#26

Hi , Thanks for your soon answer
I've another question , When you play a song , it plays like 10 or 20 secconds, Can i change it to play the whole songs?
Thanks

the player ONLY plays entire songs.
probably you are looking at the demo in this very site, where I have upload only a sample song that longs 11 seconds I think. thats way you see only 11 seconds, because its a sample of only that time
if you upload a 100 minut song, the player plays the entire 100 minuts