shithub: libvpx

Download patch

ref: 7f56cb29787b187c8cb1b778918ca3b80184c804
parent: 65dd056e413bbc42b99e9930d4914e22a0ec23cb
author: Alex Converse <[email protected]>
date: Thu Oct 8 12:01:42 EDT 2015 

Replace the zero handling in extend_to_full_distribution.

The old workaround "p = 0 ? 0 : p -1" is misleading.

?: happens before =
assigning back to p truncates to one byte.

Therefore it is equivalent to (p - 1) & 0xFF, but the check just exists
to work around a first pass bug, so let's make the work around more
clear.

https://code.google.com/p/webm/issues/detail?id=1089

Change-Id: Ia6dcc8922e1acbac0eeca23a4d564a355c489572


--- a/vp10/common/entropy.c
+++ b/vp10/common/entropy.c
@@ -403,7 +403,6 @@
   {255, 241, 243, 255, 236, 255, 252, 254},
   {255, 243, 245, 255, 237, 255, 252, 254},
   {255, 246, 247, 255, 239, 255, 253, 255},
-  {255, 246, 247, 255, 239, 255, 253, 255},
 };
 
 static const vp10_coeff_probs_model default_coef_probs_4x4[PLANE_TYPES] = {
@@ -743,14 +742,16 @@
 };
 
 static void extend_to_full_distribution(vpx_prob *probs, vpx_prob p) {
-  memcpy(probs, vp10_pareto8_full[p = 0 ? 0 : p - 1],
-         MODEL_NODES * sizeof(vpx_prob));
+  memcpy(probs, vp10_pareto8_full[p - 1], MODEL_NODES * sizeof(vpx_prob));
 }
 
 void vp10_model_to_full_probs(const vpx_prob *model, vpx_prob *full) {
   if (full != model)
     memcpy(full, model, sizeof(vpx_prob) * UNCONSTRAINED_NODES);
-  extend_to_full_distribution(&full[UNCONSTRAINED_NODES], model[PIVOT_NODE]);
+  // TODO(aconverse): model[PIVOT_NODE] should never be zero.
+  // https://code.google.com/p/webm/issues/detail?id=1089
+  if (model[PIVOT_NODE] != 0)
+    extend_to_full_distribution(&full[UNCONSTRAINED_NODES], model[PIVOT_NODE]);
 }
 
 void vp10_default_coef_probs(VP10_COMMON *cm) {
--- a/vp10/common/entropy.h
+++ b/vp10/common/entropy.h
@@ -153,7 +153,7 @@
 // 1, 3, 5, 7, ..., 253, 255
 // In between probabilities are interpolated linearly
 
-#define COEFF_PROB_MODELS 256
+#define COEFF_PROB_MODELS 255
 
 #define UNCONSTRAINED_NODES         3
 
--- a/vp9/common/vp9_entropy.c
+++ b/vp9/common/vp9_entropy.c
@@ -403,7 +403,6 @@
   {255, 241, 243, 255, 236, 255, 252, 254},
   {255, 243, 245, 255, 237, 255, 252, 254},
   {255, 246, 247, 255, 239, 255, 253, 255},
-  {255, 246, 247, 255, 239, 255, 253, 255},
 };
 
 static const vp9_coeff_probs_model default_coef_probs_4x4[PLANE_TYPES] = {
@@ -743,14 +742,16 @@
 };
 
 static void extend_to_full_distribution(vpx_prob *probs, vpx_prob p) {
-  memcpy(probs, vp9_pareto8_full[p = 0 ? 0 : p - 1],
-         MODEL_NODES * sizeof(vpx_prob));
+  memcpy(probs, vp9_pareto8_full[p - 1], MODEL_NODES * sizeof(vpx_prob));
 }
 
 void vp9_model_to_full_probs(const vpx_prob *model, vpx_prob *full) {
   if (full != model)
     memcpy(full, model, sizeof(vpx_prob) * UNCONSTRAINED_NODES);
-  extend_to_full_distribution(&full[UNCONSTRAINED_NODES], model[PIVOT_NODE]);
+  // TODO(aconverse): model[PIVOT_NODE] should never be zero.
+  // https://code.google.com/p/webm/issues/detail?id=1089
+  if (model[PIVOT_NODE] != 0)
+    extend_to_full_distribution(&full[UNCONSTRAINED_NODES], model[PIVOT_NODE]);
 }
 
 void vp9_default_coef_probs(VP9_COMMON *cm) {
--- a/vp9/common/vp9_entropy.h
+++ b/vp9/common/vp9_entropy.h
@@ -138,7 +138,7 @@
 // 1, 3, 5, 7, ..., 253, 255
 // In between probabilities are interpolated linearly
 
-#define COEFF_PROB_MODELS 256
+#define COEFF_PROB_MODELS 255
 
 #define UNCONSTRAINED_NODES         3