lavf/hevc: pad the RBSP buffer as required by the bistream reader

libavformat/hevc.c

@@ -636,7 +636,7 @@ static uint8_t *nal_unit_extract_rbsp(const uint8_t *src, uint32_t src_len,
     uint8_t *dst;
     uint32_t i, len;
 
-    dst = av_malloc(src_len);
+    dst = av_malloc(src_len + FF_INPUT_BUFFER_PADDING_SIZE);
     if (!dst)
         return NULL;