Encoder: Update scene cut detection logic

Encoder detects scene cut based on number of Intra MBs in the current
frame. For frames which contain plane areas which are different from
reference frames, encoder might encode these MBs as intra because of
lower SAD when compared with inter SAD.
Such cases were detected as scene cuts and RC model was being reset.

To fix this, scene cut is rejected if the current picture did not consume
all the bits that were allocated to it. In an actual scene cut where RC
needs to be reset, current frame consumes more than what is allocated to it.

Bug: 36814430
Change-Id: Ifa904fbaf28481f4762a23bb63e013fd37ec8942
1 file changed