Reduce filter to None if 1 pixel wide.

BUG=none
TESTED=talk media_unittest YuvScalerTest.TestScaleUp1x6OptInt
R=tpsiaki@google.com

Review URL: https://webrtc-codereview.appspot.com/5449005

git-svn-id: http://libyuv.googlecode.com/svn/trunk@906 16f28f9a-4ce2-e073-06de-1de4eb20be90

README.chromium

 Name: libyuv
 URL: http://code.google.com/p/libyuv/
-Version: 905
+Version: 906
 License: BSD
 License File: LICENSE
 

include/libyuv/version.h

@@ -11,6 +11,6 @@
 #ifndef INCLUDE_LIBYUV_VERSION_H_  // NOLINT
 #define INCLUDE_LIBYUV_VERSION_H_
 
-#define LIBYUV_VERSION 905
+#define LIBYUV_VERSION 906
 
 #endif  // INCLUDE_LIBYUV_VERSION_H_  NOLINT

source/scale_common.cc

@@ -566,6 +566,11 @@ FilterMode ScaleFilterReduce(int src_width, int src_height,
     if (dst_height == src_height || dst_height * 3 == src_height) {
       filtering = kFilterLinear;
     }
+    // TODO(fbarchard): Remove 1 pixel wide filter restriction, which is to
+    // avoid reading 2 pixels horizontally that causes memory exception.
+    if (src_width == 1) {
+      filtering = kFilterNone;
+    }
   }
   if (filtering == kFilterLinear) {
     if (src_width == 1) {
@@ -606,14 +611,14 @@ void ScaleSlope(int src_width, int src_height,
     // Scale step for bilinear sampling renders last pixel once for upsample.
     if (dst_width <= Abs(src_width)) {
       *dx = FixedDiv(Abs(src_width), dst_width);
-      *x = CENTERSTART(*dx, -32768);
+      *x = CENTERSTART(*dx, -32768);  // Subtract 0.5 (32768) to center filter.
     } else if (dst_width > 1) {
       *dx = FIXEDDIV1(Abs(src_width), dst_width);
       *x = 0;
     }
     if (dst_height <= src_height) {
       *dy = FixedDiv(src_height,  dst_height);
-      *y = CENTERSTART(*dy, -32768);  // 32768 = -0.5 to center bilinear.
+      *y = CENTERSTART(*dy, -32768);  // Subtract 0.5 (32768) to center filter.
     } else if (dst_height > 1) {
       *dy = FIXEDDIV1(src_height, dst_height);
       *y = 0;
@@ -622,7 +627,7 @@ void ScaleSlope(int src_width, int src_height,
     // Scale step for bilinear sampling renders last pixel once for upsample.
     if (dst_width <= Abs(src_width)) {
       *dx = FixedDiv(Abs(src_width), dst_width);
-      *x = CENTERSTART(*dx, -32768);
+      *x = CENTERSTART(*dx, -32768);  // Subtract 0.5 (32768) to center filter.
     } else if (dst_width > 1) {
       *dx = FIXEDDIV1(Abs(src_width), dst_width);
       *x = 0;

unit_test/unit_test.cc

@@ -19,8 +19,8 @@
 #define BENCHMARK_ITERATIONS 1
 
 libyuvTest::libyuvTest() : rotate_max_w_(128), rotate_max_h_(128),
-    benchmark_iterations_(BENCHMARK_ITERATIONS), benchmark_width_(33),
-    benchmark_height_(17) {
+    benchmark_iterations_(BENCHMARK_ITERATIONS), benchmark_width_(32),
+    benchmark_height_(24) {
     const char* repeat = getenv("LIBYUV_REPEAT");
     if (repeat) {
       benchmark_iterations_ = atoi(repeat);  // NOLINT