I don't think a frame "has" a rate factor. Put simply, and to my understanding, a relative number of bits is allocated to each frame based on its "complexity", using some magic formula. The rate factor simply is a scaling factor that is applied on top of that, in order to hit the desired total size (average bitrate) - at least in ABR and 2-Pass modes. In CRF mode, it's simply a user-defined constant. In ABR and 2-Pass mode, the rate factor gets readjusted continuously, as the "perfect" value cannot be known beforehand. You could log its current value after each frame. But how much does that tell you about the current frame? I'm not so sure... (I guess there will be more fluctuation at the beginning and less towards the end of the encode)
Last edited by LoRd_MuldeR; 9th May 2013 at 02:37.
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