From 3dc56f93f395eea2b5e102772781acc44622f6af Mon Sep 17 00:00:00 2001
From: Jean-Marc Valin <jmvalin@jmvalin.ca>
Date: Fri, 4 Mar 2016 11:18:24 -0500
Subject: [PATCH] Simplifying arithmetic by using multiply+shift
ntt_short1:
MEDIUM (%) HIGH (%)
PSNR -0.002561 0.044074
PSNRHVS 0.021798 0.082885
SSIM 0.005793 0.082526
FASTSSIM -0.054113 -0.130136
Change-Id: Icbc38383d27acb4abd3aa30c11d7fb4e51c8ce4c
---
vp10/common/dering.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/vp10/common/dering.c b/vp10/common/dering.c
index 2d5f1a7254..b7c9844a2e 100644
--- a/vp10/common/dering.c
+++ b/vp10/common/dering.c
@@ -20,10 +20,10 @@
int compute_level_from_index(int global_level, int gi) {
- static const double dering_gains[4] = {0, .7, 1, 1.4};
+ static const int dering_gains[4] = {0, 11, 16, 22};
int level;
if (global_level == 0) return 0;
- level = (int)floor(.5 + global_level*dering_gains[gi]);
+ level = (global_level*dering_gains[gi] + 8) >> 4;
return clamp(level, gi, MAX_DERING_LEVEL-1);
}
@@ -112,7 +112,7 @@ void vp10_dering_frame(YV12_BUFFER_CONFIG *frame, VP10_COMMON *cm,
#endif
/* FIXME: This is a temporary hack that uses more conservative
deringing for chroma. */
- if (pli) level = level*2/3;
+ if (pli) level = (level*5 + 4) >> 3;
if (sb_all_skip(cm, sbr*MI_BLOCK_SIZE, sbc*MI_BLOCK_SIZE)) level = 0;
threshold = level << coeff_shift;
od_dering(
--
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