CMakeLists.txt.in

cmake_minimum_required(VERSION 3.15)
project(ffmpeg-download NONE)

include(ExternalProject)
ExternalProject_Add(ffmpeg
        URL https://ffmpeg.zeranoe.com/builds/win64/dev/ffmpeg-4.2.2-win64-dev.zip
        CONFIGURE_COMMAND ""
        BUILD_COMMAND ""
        INSTALL_COMMAND "${CMAKE_COMMAND}" -E rename ${CMAKE_CURRENT_BINARY_DIR}/ffmpeg-download/ffmpeg-prefix/src/ffmpeg ${CMAKE_SOURCE_DIR}/ffmpeg
        )

ExternalProject_Get_Property(ffmpeg SOURCE_DIR DOWNLOAD_DIR)
message("src dir = ${SOURCE_DIR} ${DOWNLOAD_DIR}")