Bad x264 rc_lookahead value

[Selur]

Since I'm totally groggy today, I did the lazy approach, I called x264 with "--no-mbtree --rc-lookahead 250":

ffmpeg -y -loglevel fatal -i "G:\TestClips&Co\files\test.avi" -pix_fmt yuv420p -fps_mode passthrough -f rawvideo - | x264 --crf 18.00 --no-mbtree --rc-lookahead 250 --demuxer raw --input-res 640x352 --input-csp i420 --input-range tv --input-depth 8 --fps 25/1 --output-depth 8 --output "g:\Output\nomb_rv250.264" -

with a current x264 version.
and then called MediaInfo:

mediainfo "g:\Output\nomb_rv250.264"
General
Complete name                            : g:\Output\nomb_rv250.264
Format                                   : AVC
Format/Info                              : Advanced Video Codec
File size                                : 1.97 MiB
Duration                                 : 17 s 120 ms
Overall bit rate                         : 966 kb/s
Frame rate                               : 25.000 FPS
Writing library                          : x264 core 164 r3204 373697b
Encoding settings                        : cabac=1 / ref=3 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=11 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc=crf / mbtree=0 / crf=18.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / pb_ratio=1.30 / aq=1:1.00

Video
...

=> Like I expected, rc-lookahead isn't used. Only if mbtree is used, rb_lookahead is written into the settings.
(iirc. a few years ago x264 version still did write the rc_lookahead info, even when rc_lookahead was not used.)

Cu Selur