shithub: libvpx

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Merge "Change to KF frame boost calculation."

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

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

@@ -105,7 +105,7 @@

     fprintf(fpfile,

             "%12.0lf %12.4lf %12.2lf %12.2lf %12.2lf %12.0lf %12.4lf %12.4lf"

             "%12.4lf %12.4lf %12.4lf %12.4lf %12.4lf %12.4lf %12.4lf %12.4lf"

-            "%12.4lf %12.4lf %12.4lf %12.4lf %12.4lf %12.0lf %12.0lf %12.0lf"

+            "%12.4lf %12.4lf %12.4lf %12.4lf %12.4lf %12.0lf %12.4lf %12.0lf"

             "%12.4lf"

             "\n",

             stats->frame, stats->weight, stats->intra_error, stats->coded_error,

@@ -1970,7 +1970,20 @@

   return VPXMIN(frame_boost, GF_MAX_BOOST * boost_q_correction);

 }

-#define KF_BASELINE_ERR_PER_MB 12500.0

+static double kf_err_per_mb(VP9_COMP *cpi) {

+  const VP9_COMMON *const cm = &cpi->common;

+  unsigned int screen_area = (cm->width * cm->height);

+

+  // Use a different error per mb factor for calculating boost for

+  //  different formats.

+  if (screen_area < 1280 * 720) {

+    return 2000.0;

+  } else if (screen_area < 1920 * 1080) {

+    return 500.0;

+  }

+  return 250.0;

+}

+

 static double calc_kf_frame_boost(VP9_COMP *cpi,

                                   const FIRSTPASS_STATS *this_frame,

                                   double *sr_accumulator,

@@ -1983,7 +1996,7 @@

   const double active_area = calculate_active_area(cpi, this_frame);

   // Underlying boost factor is based on inter error ratio.

-  frame_boost = (KF_BASELINE_ERR_PER_MB * active_area) /

+  frame_boost = (kf_err_per_mb(cpi) * active_area) /

                 DOUBLE_DIVIDE_CHECK(this_frame->coded_error + *sr_accumulator);

   // Update the accumulator for second ref error difference.

@@ -1996,8 +2009,11 @@

   if (this_frame_mv_in_out > 0.0)

     frame_boost += frame_boost * (this_frame_mv_in_out * 2.0);

-  // Q correction and scalling

-  frame_boost = frame_boost * boost_q_correction;

+  // Q correction and scaling

+  // The 40.0 value here is an experimentally derived baseline minimum.

+  // This value is in line with the minimum per frame boost in the alt_ref

+  // boost calculation.

+  frame_boost = ((frame_boost + 40.0) * boost_q_correction);

   return VPXMIN(frame_boost, max_boost * boost_q_correction);

 }