• paulwilkins's avatar
    Prevent double application of min rate in two pass. · 416b7051
    paulwilkins authored
    The initial allocation of bits in the two pass code to each frame
    should be within the min max limits on the command line. However,
    when forming an ARF group the cost of the ARF is shared by frames
    in that group such that the residual bits for a frame could drop below
    the min value. This change prevents the minimum being re-applied
    after the cost of the ARF has been deducted as this may otherwise
    cause low rate sections to overshoot their target.
    Test runs comparing to a baseline run with min and max section pct
    0-2000% vs one closer to the YT use case (50-150%) suggest that
    this fix not only results in better rate control but also gives a better
    rd outcome.
    For example the HD set vs 0-2000% baseline (opsnr, ssim).
    Old code (50-150):  +0.751, +1.099
    New code(50-150): +0.241, -0.009
    Change-Id: I715da7b130bf53ba8aa609532aa9e18b84f5e2ef
vp9_ratectrl.h 10.1 KB