Add thumbnail support via ffmpeg API (incomplete

extensions/cmake/FindAVCODEC.cmake

@@ -0,0 +1,33 @@
+find_package(PkgConfig)
+if (PkgConfig_FOUND)
+    pkg_check_modules(PC_AVCODEC QUIET IMPORTED_TARGET GLOBAL libavcodec)
+endif()
+
+if (PC_AVCODEC_FOUND)
+    set(AVCODEC_FOUND TRUE)
+    set(AVCODEC_VERSION ${PC_AVCODEC_VERSION})
+    set(AVCODEC_VERSION_STRING ${PC_AVCODEC_STRING})
+    set(AVCODEC_LIBRARYS ${PC_AVCODEC_LIBRARIES})
+    if (USE_STATIC_LIBS)
+        set(AVCODEC_INCLUDE_DIRS ${PC_AVCODEC_STATIC_INCLUDE_DIRS})
+    else()
+        set(AVCODEC_INCLUDE_DIRS ${PC_AVCODEC_INCLUDE_DIRS})
+    endif()
+    if (NOT AVCODEC_INCLUDE_DIRS)
+        find_path(AVCODEC_INCLUDE_DIRS NAMES libavcodec/avcodec.h)
+    endif()
+    if (NOT TARGET AVCODEC::AVCODEC)
+        add_library(AVCODEC::AVCODEC ALIAS PkgConfig::PC_AVCODEC)
+    endif()
+else()
+    message(FATAL_ERROR "failed.")
+endif()
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(AVCODEC
+    FOUND_VAR AVCODEC_FOUND
+    REQUIRED_VARS
+        AVCODEC_LIBRARYS
+        AVCODEC_INCLUDE_DIRS
+    VERSION_VAR AVCODEC_VERSION
+)

extensions/cmake/FindAVFORMAT.cmake

@@ -0,0 +1,33 @@
+find_package(PkgConfig)
+if (PkgConfig_FOUND)
+    pkg_check_modules(PC_AVFORMAT QUIET IMPORTED_TARGET GLOBAL libavformat)
+endif()
+
+if (PC_AVFORMAT_FOUND)
+    set(AVFORMAT_FOUND TRUE)
+    set(AVFORMAT_VERSION ${PC_AVFORMAT_VERSION})
+    set(AVFORMAT_VERSION_STRING ${PC_AVFORMAT_STRING})
+    set(AVFORMAT_LIBRARYS ${PC_AVFORMAT_LIBRARIES})
+    if (USE_STATIC_LIBS)
+        set(AVFORMAT_INCLUDE_DIRS ${PC_AVFORMAT_STATIC_INCLUDE_DIRS})
+    else()
+        set(AVFORMAT_INCLUDE_DIRS ${PC_AVFORMAT_INCLUDE_DIRS})
+    endif()
+    if (NOT AVFORMAT_INCLUDE_DIRS)
+        find_path(AVFORMAT_INCLUDE_DIRS NAMES libavformat/avformat.h)
+    endif()
+    if (NOT TARGET AVFORMAT::AVFORMAT)
+        add_library(AVFORMAT::AVFORMAT ALIAS PkgConfig::PC_AVFORMAT)
+    endif()
+else()
+    message(FATAL_ERROR "failed.")
+endif()
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(AVFORMAT
+    FOUND_VAR AVFORMAT_FOUND
+    REQUIRED_VARS
+        AVFORMAT_LIBRARYS
+        AVFORMAT_INCLUDE_DIRS
+    VERSION_VAR AVFORMAT_VERSION
+)

extensions/cmake/FindAVUTIL.cmake

@@ -0,0 +1,33 @@
+find_package(PkgConfig)
+if (PkgConfig_FOUND)
+    pkg_check_modules(PC_AVUTIL QUIET IMPORTED_TARGET GLOBAL libavutil)
+endif()
+
+if (PC_AVUTIL_FOUND)
+    set(AVUTIL_FOUND TRUE)
+    set(AVUTIL_VERSION ${PC_AVUTIL_VERSION})
+    set(AVUTIL_VERSION_STRING ${PC_AVUTIL_STRING})
+    set(AVUTIL_LIBRARYS ${PC_AVUTIL_LIBRARIES})
+    if (USE_STATIC_LIBS)
+        set(AVUTIL_INCLUDE_DIRS ${PC_AVUTIL_STATIC_INCLUDE_DIRS})
+    else()
+        set(AVUTIL_INCLUDE_DIRS ${PC_AVUTIL_INCLUDE_DIRS})
+    endif()
+    if (NOT AVUTIL_INCLUDE_DIRS)
+        find_path(AVUTIL_INCLUDE_DIRS NAMES libavutil/avutil.h)
+    endif()
+    if (NOT TARGET AVUTIL::AVUTIL)
+        add_library(AVUTIL::AVUTIL ALIAS PkgConfig::PC_AVUTIL)
+    endif()
+else()
+    message(FATAL_ERROR "failed.")
+endif()
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(AVUTIL
+    FOUND_VAR AVUTIL_FOUND
+    REQUIRED_VARS
+        AVUTIL_LIBRARYS
+        AVUTIL_INCLUDE_DIRS
+    VERSION_VAR AVUTIL_VERSION
+)

extensions/cmake/FindSWSCALE.cmake

@@ -0,0 +1,32 @@
+find_package(PkgConfig)
+if (PkgConfig_FOUND)
+    pkg_check_modules(PC_SWSCALE QUIET IMPORTED_TARGET GLOBAL libswscale)
+endif()
+
+if (PC_SWSCALE_FOUND)
+    set(SWSCALE_FOUND TRUE)
+    set(SWSCALE_VERSION ${PC_SWSCALE_VERSION})
+    set(SWSCALE_VERSION_STRING ${PC_SWSCALE_STRING})
+    set(SWSCALE_LIBRARYS ${PC_SWSCALE_LIBRARIES})
+    if (USE_STATIC_LIBS)
+        set(SWSCALE_INCLUDE_DIRS ${PC_SWSCALE_STATIC_INCLUDE_DIRS})
+    else()
+        set(SWSCALE_INCLUDE_DIRS ${PC_SWSCALE_INCLUDE_DIRS})
+    endif()
+    if (NOT SWSCALE_INCLUDE_DIRS)
+        find_path(SWSCALE_INCLUDE_DIRS NAMES libswscale/swscale.h)
+    endif()
+    if (NOT TARGET SWSCALE::SWSCALE)
+        add_library(SWSCALE::SWSCALE ALIAS PkgConfig::PC_SWSCALE)
+    endif()
+else()
+    message(FATAL_ERROR "failed.")
+endif()
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(SWSCALE
+    FOUND_VAR SWSCALE_FOUND
+    REQUIRED_VARS
+        SWSCALE_LIBRARYS
+    VERSION_VAR SWSCALE_VERSION
+)