diff --git a/cmake/OpenCVFindLibsVideo.cmake b/cmake/OpenCVFindLibsVideo.cmake
index 1e2c8caab4..6133d075f8 100644
--- a/cmake/OpenCVFindLibsVideo.cmake
+++ b/cmake/OpenCVFindLibsVideo.cmake
@@ -232,6 +232,10 @@ if(WITH_FFMPEG)
         find_library(FFMPEG_SWSCALE_LIB "swscale" HINTS "${FFMPEG_LIB_DIR}")
         if(FFMPEG_CODEC_LIB AND FFMPEG_FORMAT_LIB AND
            FFMPEG_UTIL_LIB AND FFMPEG_SWSCALE_LIB)
+          set(ALIASOF_libavcodec_VERSION "Unknown")
+          set(ALIASOF_libavformat_VERSION "Unknown")
+          set(ALIASOF_libavutil_VERSION "Unknown")
+          set(ALIASOF_libswscale_VERSION "Unknown")
           set(HAVE_FFMPEG 1)
         endif()
       endif(FFMPEG_INCLUDE_DIR)