Differential encoding of probability updates
Adds differential encoding of prob updates using a subexponential
code centered around the previous probability value.
Also searches for the most cost-effective update, and breaks
up the coefficient updates into smaller groups.
Small gain on Derf: 0.2%
Change-Id: Ie0071e3dc113e3d0d7ab95b6442bb07a89970030
diff --git a/vp8/encoder/treewriter.h b/vp8/encoder/treewriter.h
index c28a0fa..42612a2 100644
--- a/vp8/encoder/treewriter.h
+++ b/vp8/encoder/treewriter.h
@@ -50,6 +50,14 @@
+ (ct[1] * vp8_cost_one(p))) >> 8;
}
+static __inline unsigned int vp8_cost_branch256(const unsigned int ct[2], vp8_prob p)
+{
+ /* Imitate existing calculation */
+
+ return ((ct[0] * vp8_cost_zero(p))
+ + (ct[1] * vp8_cost_one(p)));
+}
+
/* Small functions to write explicit values and tokens, as well as
estimate their lengths. */
