From a1f15814be0eb9921a6b5bb102354df7eeb936b2 Mon Sep 17 00:00:00 2001
From: John Koleszar <jkoleszar@google.com>
Date: Tue, 27 Nov 2012 11:16:15 -0800
Subject: Clamp decoded feature data

Not all segment feature data elements are full-range powers of two, so
there are values that can be encoded that are invalid. Add a new function
to clamp values to the maximum allowed.

Change-Id: Ie47cb80ef2d54292e6b8db9f699c57214a915bc4
---
 vp9/encoder/vp9_bitstream.c | 12 ++++++------
 vp9/encoder/vp9_boolhuff.c  | 11 ++++++++++-
 vp9/encoder/vp9_boolhuff.h  |  1 +
 3 files changed, 17 insertions(+), 7 deletions(-)

(limited to 'vp9/encoder')

diff --git a/vp9/encoder/vp9_bitstream.c b/vp9/encoder/vp9_bitstream.c
index ae8a7c616..73c116766 100644
--- a/vp9/encoder/vp9_bitstream.c
+++ b/vp9/encoder/vp9_bitstream.c
@@ -1911,19 +1911,19 @@ void vp9_pack_bitstream(VP9_COMP *cpi, unsigned char *dest,
               // Encode the relevant feature data
               if (Data < 0) {
                 Data = - Data;
-                vp9_write_literal(&header_bc, Data,
-                                  vp9_seg_feature_data_bits(j));
+                vp9_encode_unsigned_max(&header_bc, Data,
+                                        vp9_seg_feature_data_max(j));
                 vp9_write_bit(&header_bc, 1);
               } else {
-                vp9_write_literal(&header_bc, Data,
-                                  vp9_seg_feature_data_bits(j));
+                vp9_encode_unsigned_max(&header_bc, Data,
+                                        vp9_seg_feature_data_max(j));
                 vp9_write_bit(&header_bc, 0);
               }
             }
             // Unsigned data element so no sign bit needed
             else
-              vp9_write_literal(&header_bc, Data,
-                                vp9_seg_feature_data_bits(j));
+              vp9_encode_unsigned_max(&header_bc, Data,
+                                      vp9_seg_feature_data_max(j));
           } else
             vp9_write_bit(&header_bc, 0);
         }
diff --git a/vp9/encoder/vp9_boolhuff.c b/vp9/encoder/vp9_boolhuff.c
index 7619dfadf..2689ab601 100644
--- a/vp9/encoder/vp9_boolhuff.c
+++ b/vp9/encoder/vp9_boolhuff.c
@@ -8,7 +8,7 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-
+#include <assert.h>
 #include "vp9_boolhuff.h"
 
 #if defined(SECTIONBITS_OUTPUT)
@@ -64,6 +64,15 @@ void vp9_encode_value(BOOL_CODER *br, int data, int bits) {
     encode_bool(br, (1 & (data >> bit)), 0x80);
 }
 
+void vp9_encode_unsigned_max(BOOL_CODER *br, int data, int max) {
+  assert(data <= max);
+  while (max) {
+    encode_bool(br, data & 1, 128);
+    data >>= 1;
+    max >>= 1;
+  }
+}
+
 int vp9_recenter_nonneg(int v, int m) {
   if (v > (m << 1)) return v;
   else if (v >= m) return ((v - m) << 1);
diff --git a/vp9/encoder/vp9_boolhuff.h b/vp9/encoder/vp9_boolhuff.h
index 2fad86b2e..1958a41e1 100644
--- a/vp9/encoder/vp9_boolhuff.h
+++ b/vp9/encoder/vp9_boolhuff.h
@@ -37,6 +37,7 @@ typedef struct {
 extern void vp9_start_encode(BOOL_CODER *bc, unsigned char *buffer);
 
 extern void vp9_encode_value(BOOL_CODER *br, int data, int bits);
+extern void vp9_encode_unsigned_max(BOOL_CODER *br, int data, int max);
 extern void vp9_stop_encode(BOOL_CODER *bc);
 extern const unsigned int vp9_prob_cost[256];
 
-- 
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