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Old 30th April 2022, 21:33   #2  |  Link
rwill
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Join Date: Dec 2013
Posts: 343
CRF is no rate distortion algorithm but a bitrate control mode.

CRF lets you specify a constant picture QP for the whole sequence like constant QP, but in float.

This picture QP is then scaled by the 'complexity' of the local pictures if I remember correctly, someone correct me here please.

the mbtree algorithm and aq mode, which work on a macroblock level, then add to this picture QP to derive a QP for a macroblock.

I think when mbtree is enabled the complexity of a picture is always 1.0, ie no scale, but again I am not so sure about this one.

So I suggest to look at the mbtree, aq mode and bitrate control code.
There is a paper on mbtree here:
https://huyunf.github.io/blogs/2017/...tree paper.pdf
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