18.02.2025, 17:29
Your comment makes no sense. People have used VBV, zones & co. for years with proper lookahead and produced plenty of Blu-ray Discs with extremely variable bitrate adapted to each scene. VBV compliance defines transmitting, as you even pointed out!!
I think you are biased by this situation: without mbtree, rc_lookahead values exceeding fps * MAX(1.0, (vbv_bufsize / vbv_maxrate)) have no effect. This comes from the MPEG standards: data that flows in and out of the VBV can only reside there for one second at most (unless vbv ratio is > 1). In other words, current data cannot be affected by data > 1 sec in the future. Value from ]fps ; 250] have little to no impact.
With mbtree, propagation of MB metrics to the current frame can be affected by the lookahead distance, regardless of the value. Without mbtree, any values > fps does not lead to a measurable change.
I think you are biased by this situation: without mbtree, rc_lookahead values exceeding fps * MAX(1.0, (vbv_bufsize / vbv_maxrate)) have no effect. This comes from the MPEG standards: data that flows in and out of the VBV can only reside there for one second at most (unless vbv ratio is > 1). In other words, current data cannot be affected by data > 1 sec in the future. Value from ]fps ; 250] have little to no impact.
With mbtree, propagation of MB metrics to the current frame can be affected by the lookahead distance, regardless of the value. Without mbtree, any values > fps does not lead to a measurable change.