• Ronald S. Bultje's avatar
    Make get_coef_context() branchless. · 26b6318d
    Ronald S. Bultje authored
    This should significantly speedup cost_coeffs(). Basically what the
    patch does is to make the neighbour arrays padded by one item to
    prevent an eob check in get_coef_context(), then it populates each
    col/row scan and left/top edge coefficient with two times the same
    neighbour - this prevents a single/double context branch in
    get_coef_context(). Lastly, it populates neighbour arrays in pixel
    order (rather than scan order), so we don't have to dereference the
    scantable to get the correct neighbours.
    Total encoding time of first 50 frames of bus (speed 0) at 1500kbps
    goes from 2min10.1 to 2min5.3, i.e. a 2.6% overall speed increase.
    Change-Id: I42bcd2210fd7bec03767ef0e2945a665b851df56