Converts I420 planes to RGBA in one pass: each output pixel averages the box of source pixels it covers (a box
filter), read through the rotation, so scaling, rotation and color conversion happen together. The target must
be no larger than the upright source.
Converts I420 planes to RGBA in one pass: each output pixel averages the box of source pixels it covers (a box filter), read through the rotation, so scaling, rotation and color conversion happen together. The target must be no larger than the upright source.