[Mp4-tech] [H.264] FrameSkip affect lambda_scale after JM9.3

[Martin Y. Chiu]

Dear all,
        We had some experiment about B-pictures on JM. However,
    there were strange phenomena when we have changed FrameSkip
    parameter in config file. It seems that was introduced after 
    JM 9.3 by the code @ rdopt.c:3002
    double lambda_scale = (img->type == B_SLICE &&
        img->nal_reference_idc == 0 ? 1.0: 1.0 - 0.05 * (double)
        input->jumpd);
    Also it is the same in JM 9.8 slice.c:1062
    double lambda_scale = 1.0 - Clip3(0.0,0.5,0.05 * (double)
            input->jumpd);;
        What does it mean of the lambda_scale factor ?  In our 
    experiment, it introduced PSNR loss with this factor. Is there any
    docuemnt related to this parameter ? Thanks.
-- 
Regards,
    sothat