• Paul Wilkins's avatar
    Modified test for auto key frame detection. · 3606b781
    Paul Wilkins authored
    The existing test was triggering a lot of false positives on some types
    of animated material with very plain backgrounds. These were triggering
    code designed to catch key frames in letter box format clips.
    This patch tightens up the criteria and imposes a minimum requirement
    on the % blocks coded intra in the first pass and the ratio between the
    % coded intra and the modified inter % after discounting neutral (flat)
    blocks that are coded equally well either way.
    On a particular problem animation clip this change eliminated a large
    number of false positives including some cases where the old code
    selected kf several times in a row. Marginal false negatives are less
    damaging typically to compression and in the problem clip there are now
    a couple of cases where "visual" scene cuts are ignored because of well
    correlated content across the scene cut.
    Replaced some magic numbers related to this with #defines and added
    explanatory comments.
    Change-Id: Ia3d304ac60eb7e4323e3817eaf83b4752cd63ecf