[Vorbis] stereo couple

[fangchao]

Dear All:
    I studied the stereo couple documents and now confused, I wonder 
why it can be done like that, and what is the principle behind that.
I think i am confused perhaps because i have no background knowledge,
can you help me out?
Also, when doing the T/F transform,we used MDCT, so it means no imaginary part.
And i am much puzzled about the angle in the stereo couple,what does it mean?
and where does it come from ?

Thank you and looking forward to your letter!
BEST REGARDS.
 				

　　　　　　　　LISA(^_^)
　　　　　　　　fangchao_dlut at sina.com
　　　　　　　　　　2005-09-29