shithub: libvpx

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Merge "Cleaning up get_prediction_decay_rate() function."

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

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

@@ -1163,32 +1163,15 @@

 // the prediction quality is decaying from frame to frame.

 static double get_prediction_decay_rate(VP9_COMP *cpi,

                                         FIRSTPASS_STATS *next_frame) {

-  double prediction_decay_rate;

-  double second_ref_decay;

-  double mb_sr_err_diff;

-

-  // Initial basis is the % mbs inter coded

-  prediction_decay_rate = next_frame->pcnt_inter;

-

   // Look at the observed drop in prediction quality between the last frame

   // and the GF buffer (which contains an older frame).

-  mb_sr_err_diff = (next_frame->sr_coded_error - next_frame->coded_error) /

-                   cpi->common.MBs;

-  if (mb_sr_err_diff <= 512.0) {

-    second_ref_decay = 1.0 - (mb_sr_err_diff / 512.0);

-    second_ref_decay = pow(second_ref_decay, 0.5);

-    if (second_ref_decay < 0.85)

-      second_ref_decay = 0.85;

-    else if (second_ref_decay > 1.0)

-      second_ref_decay = 1.0;

-  } else {

-    second_ref_decay = 0.85;

-  }

+  const double mb_sr_err_diff = (next_frame->sr_coded_error -

+                                     next_frame->coded_error) / cpi->common.MBs;

+  const double second_ref_decay = mb_sr_err_diff <= 512.0

+      ? fclamp(pow(1.0 - (mb_sr_err_diff / 512.0), 0.5), 0.85, 1.0)

+      : 0.85;

-  if (second_ref_decay < prediction_decay_rate)

-    prediction_decay_rate = second_ref_decay;

-

-  return prediction_decay_rate;

+  return MIN(second_ref_decay, next_frame->pcnt_inter);

 }

 // Function to test for a condition where a complex transition is followed