int x264_vbv_max_bitrate = -1; // In kilobits. 0 = no limit, -1 = same as <x264_bitrate> (CBR).
int x264_vbv_buffer_size = -1; // In kilobits. 0 = one-frame VBV, -1 = same as <x264_bitrate> (one-second VBV).
std::vector<std::string> x264_extra_param; // In “key[,value]” format.
int x264_vbv_max_bitrate = -1; // In kilobits. 0 = no limit, -1 = same as <x264_bitrate> (CBR).
int x264_vbv_buffer_size = -1; // In kilobits. 0 = one-frame VBV, -1 = same as <x264_bitrate> (one-second VBV).
std::vector<std::string> x264_extra_param; // In “key[,value]” format.