"rc_init_cplx" AVOption takes over its function and this occurs transparantly.
Originally committed as revision 6277 to svn://svn.ffmpeg.org/ffmpeg/trunk
{"qdiff",HAS_ARG|OPT_EXPERT|OPT_VIDEO,{(void*)opt_qdiff},"max difference between the quantiser scale (VBR)","q"},
{"qsquish",HAS_ARG|OPT_EXPERT|OPT_VIDEO,{(void*)opt_qsquish},"how to keep quantiser between qmin and qmax (0 = clip, 1 = use differentiable function)","squish"},
{"rc_init_cplx",HAS_ARG|OPT_EXPERT|OPT_VIDEO,{(void*)opt_rc_initial_cplx},"initial complexity for 1-pass encoding","complexity"},
{"rc_eq",HAS_ARG|OPT_EXPERT|OPT_VIDEO,{(void*)opt_video_rc_eq},"set rate control equation","equation"},
{"rc_override",HAS_ARG|OPT_EXPERT|OPT_VIDEO,{(void*)opt_video_rc_override_string},"rate control override for specific intervals","override"},
{"bufsize",HAS_ARG|OPT_VIDEO,{(void*)opt_video_buffer_size},"set ratecontrol buffer size (in kByte)","size"},