diff --git a/libavformat/avidec.c b/libavformat/avidec.c
index 7093e9150d..2175374e6e 100644
--- a/libavformat/avidec.c
+++ b/libavformat/avidec.c
@@ -1001,8 +1001,10 @@ static int avi_load_index(AVFormatContext *s)
     ByteIOContext *pb = s->pb;
     uint32_t tag, size;
     int64_t pos= url_ftell(pb);
+    int ret = -1;
 
-    url_fseek(pb, avi->movi_end, SEEK_SET);
+    if (url_fseek(pb, avi->movi_end, SEEK_SET) < 0)
+        goto the_end; // maybe truncated file
 #ifdef DEBUG_SEEK
     printf("movi_end=0x%"PRIx64"\n", avi->movi_end);
 #endif
@@ -1023,19 +1025,20 @@ static int avi_load_index(AVFormatContext *s)
         case MKTAG('i', 'd', 'x', '1'):
             if (avi_read_idx1(s, size) < 0)
                 goto skip;
-            else
+            ret = 0;
                 goto the_end;
             break;
         default:
         skip:
             size += (size & 1);
-            url_fskip(pb, size);
+            if (url_fseek(pb, size, SEEK_CUR) < 0)
+                goto the_end; // something is wrong here
             break;
         }
     }
  the_end:
     url_fseek(pb, pos, SEEK_SET);
-    return 0;
+    return ret;
 }
 
 static int avi_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)