Can we set min bitrate for CRF mode encode?

[iKron]

is there anyway we can set min bitrate for CRF mode? in CRF mode dark scene looks really bad. so i want to set min bitrate to make the dark scene better.

[poisondeathray]

is there anyway we can set min bitrate for CRF mode? in CRF mode dark scene looks really bad. so i want to set min bitrate to make the dark scene better.

Not directly ; but you can influence a certain minimum quality indirectly


You can set a hard limit on qpmax, but it's probably not what you want - it can negatively impact other sections, especially simple sections like titles etc.. will be overdistributed

You can play with aq modes (mode 3 places bias to dark scenes specifically) and aq strengths, qcomp - but that will usually increase bitrate everywhere , not just dark scenes. ie. Filesize will usually be much larger than what it has to be.

Or you can either specify zones manually, such as a bitrate multipler over specific sections. That is probably the most effective, but the most work, because you have to identify ranges

[sekininsha]

identify the dark film frame ranges and apply crf by zones.. eg (in x264)

--zones 21140,21380,crf=15/55973,59840,crf=15/79880,80267,crf=15

[iKron]

thanks for reply, i used qpmax 27, looks better now