ref: 84520829ed508a24e66b05b5202f5fca77443f75
parent: f215c641bb0e3245302fe60e6f98a4583da59c54
author: Dmitry Kovalev <dkovalev@google.com>
date: Fri Jan 3 07:11:36 EST 2014
Cleaning up get_prediction_decay_rate() function. Change-Id: Ie8fcee21f41f91f94b4fa02f2a55691dea1734e3
--- 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