X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;ds=sidebyside;f=libavcodec%2Fsvq1dec.c;h=83fe07e4c7c463ac871675108e30fca1979b575a;hb=c48883163d6c7ff0806687bf3ee33ca9f8e7dede;hp=abd8adc6d174584b15d7c5f3bde3726705658c27;hpb=92afb431621c79155fcb7171d26f137eb1bee028;p=ffmpeg

diff --git a/libavcodec/svq1dec.c b/libavcodec/svq1dec.c
index abd8adc6d17..83fe07e4c7c 100644
--- a/libavcodec/svq1dec.c
+++ b/libavcodec/svq1dec.c
@@ -195,7 +195,8 @@ static const uint8_t string_table[256] = {
 
 #define SVQ1_CALC_CODEBOOK_ENTRIES(cbook)\
       codebook = (const uint32_t *) cbook[level];\
-      bit_cache = get_bits (bitbuf, 4*stages);\
+      if (stages > 0)\
+        bit_cache = get_bits (bitbuf, 4*stages);\
       /* calculate codebook entries for this vector */\
       for (j=0; j < stages; j++) {\
         entries[j] = (((bit_cache >> (4*(stages - j - 1))) & 0xF) + 16*j) << (level + 1);\
@@ -317,9 +318,9 @@ static int svq1_decode_motion_vector (GetBitContext *bitbuf, svq1_pmv *mv, svq1_
 
     /* add median of motion vector predictors and clip result */
     if (i == 1)
-      mv->y = ((diff + mid_pred(pmv[0]->y, pmv[1]->y, pmv[2]->y)) << 26) >> 26;
+      mv->y = sign_extend(diff + mid_pred(pmv[0]->y, pmv[1]->y, pmv[2]->y), 6);
     else
-      mv->x = ((diff + mid_pred(pmv[0]->x, pmv[1]->x, pmv[2]->x)) << 26) >> 26;
+      mv->x = sign_extend(diff + mid_pred(pmv[0]->x, pmv[1]->x, pmv[2]->x), 6);
   }
 
   return 0;