since code now use get_bits_long, allocate padding buffer

Originally committed as revision 18138 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/mov.c

@@ -1166,7 +1166,7 @@ static int mov_read_stsz(MOVContext *c, ByteIOContext *pb, MOVAtom atom)
 
     num_bytes = (entries*field_size+4)>>3;
 
-    buf = av_malloc(num_bytes);
+    buf = av_malloc(num_bytes+FF_INPUT_BUFFER_PADDING_SIZE);
     if (!buf) {
         av_freep(&sc->sample_sizes);
         return AVERROR(ENOMEM);