• Yaowu Xu's avatar
    adjusting the calculation of errorperbit · 10ed60dc
    Yaowu Xu authored
    RDMULT/RDDIV defines a bit worth of distortion in term of sum squared
    difference. This has also been used as errorperbit in subpixel motion
    search, where the distortions computed as variance of the difference.
    The variance of differences is different from sum squared differences
    by amount of DC squared. Typically, for inter predicted MBs, this
    difference averages around 10% between the two distortion, so this patch
    introduces a 110% constant in deriving errorperbit from RDMULT/RDDIV.
    Test on CIF set shows small but positive gain on overall PSNR (.03%)
    and SSIM (.07%), overall impact on average PSNR is 0.
    Change-Id: I95425f922d037b4d96083064a10c7cdd4948ee62