Hi... i am a newbie... Can U help me...?

* Where can i find the audio codec tutorial like amr_wb, amr_nb, aac?
* I have encode the mpg file to 3gp file with ffmpeg :

ffmpeg -i nama.mpg -b 10 -r 10 -vcodec h263 -ar 16000 -ab 100 -acodec amr_wb -ac 1 hasil.3gp

That's success but i can't hear the audio. What's i am wrong?
If i use -acodec amr_nb -ar 8000, that's nicely the mono audio i can hear
How about i use acodec aac ?

* How to encode video file to rm file ( Real Media ). I use vcodec rv10 but i don't know the audiocodec. Can u help me...

* I 've configure MPlayer and success but in make there's an error :
make : *** [libvo/libvo.a] Error 2

I hope u all can help me..
Thanks before..