shithub: libvpx

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Add zoom break out for kf boost loop.

Adds a breakout threshold to key frame boost loop.

This reduces the boost somewhat in cases where there is a
significant zoom component. In tests most clips no effect
but a sizable gain for some clips like station.

Change-Id: I8b7a4d57f7ce5f4e3faab3f5688f7e4d61679b9a

--- a/vp9/encoder/vp9_firstpass.c

+++ b/vp9/encoder/vp9_firstpass.c

@@ -2815,6 +2815,7 @@

 #define FRAMES_TO_CHECK_DECAY 8

 #define MIN_KF_TOT_BOOST 300

 #define KF_BOOST_SCAN_MAX_FRAMES 32

+#define KF_ABS_ZOOM_THRESH 6.0

 #ifdef AGGRESSIVE_VBR

 #define KF_MAX_FRAME_BOOST 80.0

@@ -2842,6 +2843,7 @@

   double kf_group_err = 0.0;

   double recent_loop_decay[FRAMES_TO_CHECK_DECAY];

   double sr_accumulator = 0.0;

+  double abs_mv_in_out_accumulator = 0.0;

   const double av_err = get_distribution_av_err(cpi, twopass);

   vp9_zero(next_frame);

@@ -3021,7 +3023,14 @@

                                         KF_MAX_FRAME_BOOST * zm_factor);

       boost_score += frame_boost;

-      if (frame_boost < 25.00) break;

+

+      // Measure of zoom. Large zoom tends to indicate reduced boost.

+      abs_mv_in_out_accumulator +=

+          fabs(next_frame.mv_in_out_count * next_frame.pcnt_motion);

+

+      if ((frame_boost < 25.00) ||

+          (abs_mv_in_out_accumulator > KF_ABS_ZOOM_THRESH))

+        break;

     } else {

       break;

     }