编码设置 : cabac=1 / ref=4 / deblock=1:-3:-3 / analyse=0x3:0x113 / me=umh / subme=10 / psy=1 / psy_rd=1.00:0.05 / mixed_ref=1 / me_range=32 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=0 / chroma_qp_offset=-2 / threads=18 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=4 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc=2pass / mbtree=0 / bitrate=10000 / ratetol=1.0 / qcomp=0.70 / qpmin=0 / qpmax=69 / qpstep=4 / cplxblur=20.0 / qblur=0.5 / ip_ratio=1.40 / pb_ratio=1.30 / aq=2:1.00
编码设置 : cabac=1 / ref=4 / deblock=1:-3:-3 / analyse=0x3:0x113 / me=umh / subme=10 / psy=1 / psy_rd=1.00:0.05 / mixed_ref=0 / me_range=24 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-3 / threads=3 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=1 / constrained_intra=0 / bframes=3 / b_pyramid=1 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=1 / weightp=1 / keyint=24 / keyint_min=1 / scenecut=40 / intra_refresh=0 / rc=crf / mbtree=0 / crf=18.0 / qcomp=0.70 / qpmin=10 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / pb_ratio=1.30 / aq=1:1.00
第一组是chd的，第二组是自己的。
请教一下 chroma_qp_offset=-2 / chroma_qp_offset=-3 /这个参数为什么有区别，谢谢！

记得这个如果没指定，是x264自动设置的
/* Psy RDO increases overall quantizers to improve the quality of luma--this indirectly hurts chroma quality */
/* so we lower the chroma QP offset to compensate */
/* This can be triggered repeatedly on multiple calls to parameter_validate, but since encoding
* uses the pps chroma qp offset not the param chroma qp offset, this is not a problem. */
if( h->mb.i_psy_rd )
h->param.analyse.i_chroma_qp_offset -= h->param.analyse.f_psy_rd < 0.25 ? 1 : 2;
h->mb.i_psy_trellis = FIX8( h->param.analyse.f_psy_trellis / 4 );
/* Psy trellis has a similar effect. */
if( h->mb.i_psy_trellis )
h->param.analyse.i_chroma_qp_offset -= h->param.analyse.f_psy_trellis < 0.25 ? 1 : 2;
If psy-rd is on (not set to zero), do the following:
If the psy-rd value is less than 0.25 then subtract 1 from chroma_qp_offset, otherwise subtract 2.
If psy-trellis is on (not set to zero), do the following:
If the psy-trellis value is less than 0.25 then subtract 1 from chroma_qp_offset, otherwise subtract 2.
可能你或者CHD手动指定了这个参数