[x264-devel] some questions about Trellis RD

[lurui]

Hello:
In the nearly added Trellis RD code,I can not understand below:
1.What is the lambda2_tab[] means? Why we multipied the normal lambda by 1024?
2.Why the cost is 
    n.score += f8_bits * i_lambda2 >> ( CABAC_SIZE_BITS - LAMBDA_BITS );? 
I think CABAC_SIZE_BITS is needed for f8_bits, but I can't understand where the LAMBDA_BITS come from?

Can someone explains these questions?