[BUG] x264 open_gop error in Scenarist BD

[Selur]

Key it gets restricted by Level&Profile restrictions, which are Profile: High and Level: 4.1 for Blu-rays.
For the general calculation:

/***
* restrictions:
* MaxMBPS >= width*height*fps. (w&h measured in macroblocks, i.e. pixels/16 round up in each dimension)
* sqrt(MaxFS*8)*16 >= width
* sqrt(MaxFS*8)*16 >= height
* f) PicWidthInMbs <= Sqrt( MaxFS * 8 )
* FrameHeightInMbs <= Sqrt( MaxFS * 8 )
* MaxDPB >= (bytes in a frame) * min(16, ref + (pyramid ? 2 : bframes ? 1 : 0))
* MaxBR >= vbv_maxrate.
* MaxCPB >= vbv_bufsize.
* MaxVmvR >= max_mv_range.
* MaxMvsPer2Mb, MinLumaBiPredSize, direct_8x8_inference_flag : are not enforced by x264. The only way to ensure compliance is to disable p4x4 at level>=3.1, or at level>=3 w/ B-frames.
* MinCR : is not enforced by x264. Won't ever be an issue unless you use lossless.
* SliceRate : I don't know what this limits.
*
* legend:
* MaxDPB = max decoded picture buffer
* MaxMBPS = max macroblocks per second
* MaxFS = max frame size in macroblocks
* MaxBR = max bitrate
* MaxCPB = max vbv buffer
* MaxVmvR = max motion vetor range
* **/

see also: https://forum.doom9.org/showthread.php?t=142758

Cu Selur