• Steinar Midtskogen's avatar
    Move CLPF block signals from frame to SB level. · 97535038
    Steinar Midtskogen authored
    These signals were in the uncompressed frame header (as a temporary
    hack), which caused two problems:
    * We don't want that header to be duplicated in the slice header
    * It was necessary to signal the number of bits to transmit up front
    However, the filter size can be 128x128 which is greater than the SB
    size, and a decoder wouldn't be able to know whether to read a bit or
    not until the final SB of that 128x128 block has been decoded
    (depending on whether the 128x128 is all skip or not).  Therefore the
    signalling was changed for 128x128 blocks so that every top left SB of
    a 128x128 filter block contains a signal regardless of whether the
    block is all skip or not.  Also, all the MB's of 128x128 block are
    filtered even if they are skip MB's.  This gives the signal a purpose
    even when the 128x128 block is all skip, and it also gives a slight
    coding gain as it leaves a way to filter skip blocks, which was
    previously forbidden.
    Low latency:
    PSNR YCbCr:     -0.19%     -0.14%     -0.06%
       PSNRHVS:     -0.15%
          SSIM:     -0.13%
        MSSSIM:     -0.15%
     CIEDE2000:     -0.19%
    High latency:
    PSNR YCbCr:     -0.03%     -0.01%     -0.09%
       PSNRHVS:      0.04%
          SSIM:      0.00%
        MSSSIM:      0.02%
     CIEDE2000:     -0.02%
    Change-Id: I69ba7144d07d388b4f0968f6a53558f480979171