diff --git a/README.chromium b/README.chromium
index a0afc9dfb..767780475 100644
--- a/README.chromium
+++ b/README.chromium
@@ -1,6 +1,6 @@
 Name: libyuv
 URL: http://code.google.com/p/libyuv/
-Version: 445
+Version: 446
 License: BSD
 License File: LICENSE
 
diff --git a/include/libyuv/planar_functions.h b/include/libyuv/planar_functions.h
index f0bae55b6..688bef5dc 100644
--- a/include/libyuv/planar_functions.h
+++ b/include/libyuv/planar_functions.h
@@ -74,6 +74,17 @@ int I420Mirror(const uint8* src_y, int src_stride_y,
                uint8* dst_u, int dst_stride_u,
                uint8* dst_v, int dst_stride_v,
                int width, int height);
+
+// Alias
+#define I400ToI400Mirror I400Mirror
+
+// I400 mirror.  A single plane is mirrored horizontally.
+// Pass negative height to achieve 180 degree rotation.
+LIBYUV_API
+int I400Mirror(const uint8* src_y, int src_stride_y,
+               uint8* dst_y, int dst_stride_y,
+               int width, int height);
+
 // Alias
 #define ARGBToARGBMirror ARGBMirror
 
diff --git a/include/libyuv/version.h b/include/libyuv/version.h
index da99c5e97..e5c9c063e 100644
--- a/include/libyuv/version.h
+++ b/include/libyuv/version.h
@@ -11,6 +11,6 @@
 #ifndef INCLUDE_LIBYUV_VERSION_H_  // NOLINT
 #define INCLUDE_LIBYUV_VERSION_H_
 
-#define LIBYUV_VERSION 445
+#define LIBYUV_VERSION 446
 
 #endif  // INCLUDE_LIBYUV_VERSION_H_  NOLINT
diff --git a/source/planar_functions.cc b/source/planar_functions.cc
index 2d0366fbf..6de5f0342 100644
--- a/source/planar_functions.cc
+++ b/source/planar_functions.cc
@@ -247,6 +247,26 @@ int UYVYToI422(const uint8* src_uyvy, int src_stride_uyvy,
   return 0;
 }
 
+// Mirror I400 with optional flipping
+LIBYUV_API
+int I400Mirror(const uint8* src_y, int src_stride_y,
+               uint8* dst_y, int dst_stride_y,
+               int width, int height) {
+  if (!src_y || !dst_y ||
+      width <= 0 || height == 0) {
+    return -1;
+  }
+  // Negative height means invert the image.
+  if (height < 0) {
+    height = -height;
+    src_y = src_y + (height - 1) * src_stride_y;
+    src_stride_y = -src_stride_y;
+  }
+
+  MirrorPlane(src_y, src_stride_y, dst_y, dst_stride_y, width, height);
+  return 0;
+}
+
 // Mirror I420 with optional flipping
 LIBYUV_API
 int I420Mirror(const uint8* src_y, int src_stride_y,
diff --git a/unit_test/convert_test.cc b/unit_test/convert_test.cc
index 36739526b..e5d161d95 100644
--- a/unit_test/convert_test.cc
+++ b/unit_test/convert_test.cc
@@ -706,6 +706,7 @@ TESTATOB(BayerGBRG, 1, 1, ARGB, 4, 0)
 TESTATOB(BayerGRBG, 1, 1, ARGB, 4, 0)
 TESTATOB(I400, 1, 1, ARGB, 4, 0)
 TESTATOB(I400, 1, 1, I400, 1, 0)
+TESTATOB(I400, 1, 1, I400Mirror, 1, 0)
 TESTATOB(ARGB, 4, 4, ARGBMirror, 4, 0)
 
 #define TESTATOBRANDOM(FMT_A, BPP_A, STRIDE_A, FMT_B, BPP_B, STRIDE_B, DIFF)   \
@@ -771,6 +772,7 @@ TESTATOBRANDOM(I400, 1, 1, ARGB, 4, 4, 0)
 TESTATOBRANDOM(YUY2, 4, 2, ARGB, 4, 4, 0)
 TESTATOBRANDOM(UYVY, 4, 2, ARGB, 4, 4, 0)
 TESTATOBRANDOM(I400, 1, 1, I400, 1, 1, 0)
+TESTATOBRANDOM(I400, 1, 1, I400Mirror, 1, 1, 0)
 TESTATOBRANDOM(ARGB, 4, 4, ARGBMirror, 4, 4, 0)
 
 TEST_F(libyuvTest, Test565) {