decode motion & modulo optimize patch by (BERO <bero at geocities dot co dot jp>)

Originally committed as revision 1872 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 5 insertions, 3 deletions

diff --git a/libavcodec/msmpeg4.c b/libavcodec/msmpeg4.c
index df39315854..e4daec4e8f 100644
--- a/libavcodec/msmpeg4.c
+++ b/libavcodec/msmpeg4.c
@@ -1481,10 +1481,12 @@ static int msmpeg4v2_decode_motion(MpegEncContext * s, int pred, int f_code)
         return pred;
     sign = get_bits1(&s->gb);
     shift = f_code - 1;
-    val = (code - 1) << shift;
-    if (shift > 0)
+    val = code;
+    if (shift) {
+        val = (val - 1) << shift;
         val |= get_bits(&s->gb, shift);
-    val++;
+        val++;
+    }
     if (sign)
         val = -val;