commit ff3b2fb36b59036caaecc8c5d9cc23042d1cb4e8
author Hui Su <huisu@google.com> Fri Mar 16 13:00:30 2018 -0700
committer Hui Su <huisu@google.com> Sat Mar 17 22:16:51 2018 +0000
tree 5226ec0265d0dacf14f108d839bccc7807320ffb
parent 0cbcf79819ec17344335ec93c1a40994483088eb

[normative]palette_delta_encoding: don't waste bit

When the range is less than 2, we don't need to transmit any bits,
but we still transmited 1 bit that is always 0. This patch makes the
codec skip this unnecessary bit.

Tested on the screen_content testset, no coding stats changes.

BUG=aomedia:1604

Change-Id: Ia21b669aea00fd94852559affd69fa25895fd368

av1/common/entropymode.h

diff --git a/av1/common/entropymode.h b/av1/common/entropymode.h
index 45c3ba5..750c214 100644
--- a/av1/common/entropymode.h
+++ b/av1/common/entropymode.h
@@ -298,6 +298,7 @@
 void av1_setup_past_independence(struct AV1Common *cm);
 
 static INLINE int av1_ceil_log2(int n) {
+  if (n < 2) return 0;
   int i = 1, p = 2;
   while (p < n) {
     i++;