From f21fb76b1be18036c93c3e29fe1889a9fabf30b3 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Tue, 21 Jun 2011 16:14:19 -0400
Subject: [PATCH] ac3enc: remove a branch in asym_quant() by doing 2 shifts
---
libavcodec/ac3enc.c | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)
diff --git a/libavcodec/ac3enc.c b/libavcodec/ac3enc.c
index 1db69414a57..db45c8360e7 100644
--- a/libavcodec/ac3enc.c
+++ b/libavcodec/ac3enc.c
@@ -1123,15 +1123,9 @@ static inline int sym_quant(int c, int e, int levels)
*/
static inline int asym_quant(int c, int e, int qbits)
{
- int lshift, m, v;
+ int m, v;
- lshift = e + qbits - 24;
- if (lshift >= 0)
- v = c << lshift;
- else
- v = c >> (-lshift);
- /* rounding */
- v = (v + 1) >> 1;
+ v = (((c << e) >> (24 - qbits)) + 1) >> 1;
m = (1 << (qbits-1));
if (v >= m)
v = m - 1;
--
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