[FFmpeg-cvslog] mpeg12enc: use sign_extend() function

[Mans Rullgard]

ffmpeg | branch: release/0.8 | Mans Rullgard <mans at mansr.com> | Sat Oct  8 12:56:54 2011 +0100| [48f9a800722736c9fd1ed37562a8760417f8f221] | committer: Reinhard Tartler

mpeg12enc: use sign_extend() function

Signed-off-by: Mans Rullgard <mans at mansr.com>
(cherry picked from commit 2f329db90e5d72ad383a0ba05fde3641a34ef73b)

Signed-off-by: Anton Khirnov <anton at khirnov.net>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=48f9a800722736c9fd1ed37562a8760417f8f221
---

 libavcodec/mpeg12enc.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/mpeg12enc.c b/libavcodec/mpeg12enc.c
index eb07ecf..f77677a 100644
--- a/libavcodec/mpeg12enc.c
+++ b/libavcodec/mpeg12enc.c
@@ -27,6 +27,7 @@
 
 #include "avcodec.h"
 #include "dsputil.h"
+#include "mathops.h"
 #include "mpegvideo.h"
 
 #include "mpeg12.h"
@@ -681,8 +682,7 @@ static void mpeg1_encode_motion(MpegEncContext *s, int val, int f_or_b_code)
         int bit_size = f_or_b_code - 1;
         int range = 1 << bit_size;
         /* modulo encoding */
-        int l= INT_BIT - 5 - bit_size;
-        val= (val<<l)>>l;
+        val = sign_extend(val, 5 + bit_size);
 
         if (val >= 0) {
             val--;