Fix issue with short static KF groups.

Where a KF group is very short but static make sure
it is coded as a single GF group. Previously there was a
bug where such groups could be coded as an arf group
with the arf in the next scene.

Change-Id: I4504ae2b03c4877fcecfa58dd503879aa4eefac4

diff --git a/vp9/encoder/vp9_firstpass.c b/vp9/encoder/vp9_firstpass.c
index 8e6b3be..d130edf 100644 (file)
--- a/vp9/encoder/vp9_firstpass.c
+++ b/vp9/encoder/vp9_firstpass.c
@@ -2917,6 +2917,7 @@ static void define_gf_group(VP9_COMP *cpi, FIRSTPASS_STATS *this_frame) {
 
   // Should we use the alternate reference frame.
   if ((zero_motion_accumulator < 0.995) && allow_alt_ref &&
+      (twopass->kf_zeromotion_pct < STATIC_KF_GROUP_THRESH) &&
       (i < cpi->oxcf.lag_in_frames) && (i >= rc->min_gf_interval)) {
     const int forward_frames = (rc->frames_to_key - i >= i - 1)
                                    ? i - 1