// We do three calculations for kf size.
// The first is based on the error score for the whole kf group.
- // The second (optionaly) on the key frames own error if this is smaller than the average for the group.
- // The final one insures that the frame receives at least the allocation it would have received based on its own error score vs the error score remaining
-
- allocation_chunks = ((cpi->twopass.frames_to_key - 1) * 100) + kf_boost; // cpi->twopass.frames_to_key-1 because key frame itself is taken care of by kf_boost
+ // The second (optionaly) on the key frames own error if this is
+ // smaller than the average for the group.
+ // The final one insures that the frame receives at least the
+ // allocation it would have received based on its own error score vs
+ // the error score remaining
+ // Special case if the sequence appears almost totaly static
+ // as measured by the decay accumulator. In this case we want to
+ // spend almost all of the bits on the key frame.
+ // cpi->twopass.frames_to_key-1 because key frame itself is taken
+ // care of by kf_boost.
+ if ( decay_accumulator >= 0.99 )
+ {
+ allocation_chunks =
+ ((cpi->twopass.frames_to_key - 1) * 10) + kf_boost;
+ }
+ else
+ {
+ allocation_chunks =
+ ((cpi->twopass.frames_to_key - 1) * 100) + kf_boost;
+ }
// Normalize Altboost and allocations chunck down to prevent overflow
while (kf_boost > 1000)