92526469d9
Tested the alternative I recorded last iteration. Parsing every bundle's keyframe times (2985/2985 parse), the derived-summary reading -- (high,low) == (min,max) keyframe time -- holds in 6 of 2985 (0.2%). The apparent 34.2% match on 'high == min' is a coincidence of zeros: the minimum keyframe time is 0 in 96% of bundles and high is 0 in 34.9%, so the 1022 'matches' are exactly the both-zero cases. Worth noting that last iteration I declined to treat the high==0 share as support -- it turned out to be the confound rather than the signal. The interval is also narrow: (low-high)/(max-min) has a median of 0.019, about 2% of the keyframe span. It lies inside the keyframe range in 88.6%, entirely after in 174 and entirely before in 68. A short authored window is not the shape of a playback range or a whole-animation loop region, so those readings weaken too. What it is stays open.