mpeg124: use sign_extend() function

Signed-off-by: Mans Rullgard <mans@mansr.com>

1 files changed, 2 insertions, 3 deletions

diff --git a/libavcodec/ituh263enc.c b/libavcodec/ituh263enc.c
index 383a81b0e1..783a04f64d 100644
--- a/libavcodec/ituh263enc.c
+++ b/libavcodec/ituh263enc.c
@@ -657,7 +657,7 @@ void h263_encode_mb(MpegEncContext * s,
 
 void ff_h263_encode_motion(MpegEncContext * s, int val, int f_code)
 {
-    int range, l, bit_size, sign, code, bits;
+    int range, bit_size, sign, code, bits;
 
     if (val == 0) {
         /* zero vector */
@@ -667,8 +667,7 @@ void ff_h263_encode_motion(MpegEncContext * s, int val, int f_code)
         bit_size = f_code - 1;
         range = 1 << bit_size;
         /* modulo encoding */
-        l= INT_BIT - 6 - bit_size;
-        val = (val<<l)>>l;
+        val = sign_extend(val, 6 + bit_size);
         sign = val>>31;
         val= (val^sign)-sign;
         sign&=1;