shithub: libvpx

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ref: 3b95a46c5538ad4c5b765923d61d8d1b12a4569a
parent: 8fa38096a39433c6b86848dce0e307acd2a54482
author: Yaowu Xu <yaowu@google.com>
date: Tue Aug 10 17:12:04 EDT 2010 

Normalize quantizer's zero bin and rounding factors

This patch changes a few numbers in the two constant arrays
for quantizer's zerobin and rounding factors, in general to
make the sum of the two factors for any Q to be 128.  While
it might be beneficial to calibrate the two arrays for best
quantizer performance, it is not the purpose of this patch.
Normalizing the two arrays will enable quick optimization
of the current faster quantizer, i.e .zerobin check can be
removed.

Change-Id: If9abfd7929bf4b8e9ecd64a79d817c6728c820bd


--- a/vp8/encoder/encodeframe.c
+++ b/vp8/encoder/encodeframe.c
@@ -60,10 +60,10 @@
 unsigned int b_modes[14]  = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
 #endif
 
-// The first four entries are dummy values
 static const int qrounding_factors[129] =
 {
-    56, 56, 56, 56, 56, 56, 56, 56,
+    56, 56, 56, 56, 48, 48, 56, 56,
+    48, 48, 48, 48, 48, 48, 48, 48,
     48, 48, 48, 48, 48, 48, 48, 48,
     48, 48, 48, 48, 48, 48, 48, 48,
     48, 48, 48, 48, 48, 48, 48, 48,
@@ -78,13 +78,12 @@
     48, 48, 48, 48, 48, 48, 48, 48,
     48, 48, 48, 48, 48, 48, 48, 48,
     48, 48, 48, 48, 48, 48, 48, 48,
-    48, 48, 48, 48, 48, 48, 48, 48,
     48,
 };
 
 static const int qzbin_factors[129] =
 {
-    64, 64, 64, 64, 80, 80, 80, 80,
+    72, 72, 72, 72, 80, 80, 72, 72,
     80, 80, 80, 80, 80, 80, 80, 80,
     80, 80, 80, 80, 80, 80, 80, 80,
     80, 80, 80, 80, 80, 80, 80, 80,