Prepare Release Candidate for libvpx v1.4.0

Change-Id: I9ffd30c88a5e40c555bde1f5efcf8a3c9ffcf5ff
diff --git a/CHANGELOG b/CHANGELOG
index 97c9a7b..6ba1f6c 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,23 @@
+2015-03-23 v1.4.0 "Indian Runner Duck"
+  This release includes significant improvements to the VP9 codec.
+
+  - Upgrading:
+    This release is ABI incompatible with 1.3.0. It drops the compatibility
+    layer, requiring VPX_IMG_FMT_* instead of IMG_FMT_*, and adds several codec
+    controls for VP9.
+
+  - Enhancements:
+    Faster VP9 encoding and decoding
+    Multithreaded VP9 decoding (tile and frame-based)
+    Multithreaded VP9 encoding - on by default
+    YUV 4:2:2 and 4:4:4 support in VP9
+    10 and 12bit support in VP9
+    64bit ARM support by replacing ARM assembly with intrinsics
+
+  - Bug Fixes:
+    Fixes a VP9 bitstream issue in Profile 1. This only affected non-YUV 4:2:0
+    files.
+
 2013-11-15 v1.3.0 "Forest"
   This release introduces the VP9 codec in a backward-compatible way.
   All existing users of VP8 can continue to use the library without