[FFmpeg-devel] Help needed with ratecontrol

[Kostya]

As you may know, I'm working on AAC encoder.
Today I've managed to add trellis-based scalefactor quantizer selection.
While it looks like optimal selection (at least in terms of time spent
on search :-S, but I'm pretty sure it's optimal except for quantization
procedure itself), it depends on parameter lambda which I don't know
how to control.

Can somebody tell me how to manipulate lambda to achieve desired bitrate?
I'm not sure I can use ratecontrol.c for that (it's too complex
and mpegvideo-oriented).

Code snippets and links to clear papers are accepted.

Thanks.