vgmstream/cmake/FindFFmpeg.cmake

# vim: ts=2 sw=2
# - Try to find the required ffmpeg components(default: AVFORMAT, AVUTIL, AVCODEC)
#
# Once done this will define
#  FFMPEG_FOUND         - System has the all required components.
#  FFMPEG_INCLUDE_DIRS  - Include directory necessary for using the required components headers.
#  FFMPEG_LIBRARIES     - Link these to use the required ffmpeg components.
#  FFMPEG_DEFINITIONS   - Compiler switches required for using the required ffmpeg components.
#
# For each of the components it will additionally set.
#   - AVCODEC
#   - AVDEVICE
#   - AVFORMAT
#   - AVFILTER
#   - AVUTIL
#   - POSTPROC
#   - SWSCALE
# the following variables will be defined
#  <component>_FOUND        - System has <component>
#  <component>_INCLUDE_DIRS - Include directory necessary for using the <component> headers
#  <component>_LIBRARIES    - Link these to use <component>
#  <component>_DEFINITIONS  - Compiler switches required for using <component>
#  <component>_VERSION      - The components version
#
# Copyright (c) 2006, Matthias Kretz, <kretz@kde.org>
# Copyright (c) 2008, Alexander Neundorf, <neundorf@kde.org>
# Copyright (c) 2011, Michael Jansen, <kde@michael-jansen.biz>
#
# Redistribution and use is allowed according to the terms of the BSD license.
# For details see the accompanying COPYING-CMAKE-SCRIPTS file.

# Comes from https://github.com/snikulov/cmake-modules/blob/master/FindFFmpeg.cmake

include(FindPackageHandleStandardArgs)

# The default components were taken from a survey over other FindFFMPEG.cmake files
if(NOT FFmpeg_FIND_COMPONENTS)
	set(FFmpeg_FIND_COMPONENTS AVCODEC AVFORMAT AVUTIL)
endif()

#
### Macro: set_component_found
#
# Marks the given component as found if both *_LIBRARIES AND *_INCLUDE_DIRS is present.
#
macro(set_component_found _component)
	if(${_component}_LIBRARIES AND ${_component}_INCLUDE_DIRS)
		# message(STATUS "  - ${_component} found.")
		set(${_component}_FOUND TRUE)
	else()
		# message(STATUS "  - ${_component} not found.")
	endif()
endmacro()

#
### Macro: find_component
#
# Checks for the given component by invoking pkgconfig and then looking up the libraries and
# include directories.
#
macro(find_component _component _pkgconfig _library _header)
	if(NOT WIN32)
		# use pkg-config to get the directories and then use these values
		# in the FIND_PATH() and FIND_LIBRARY() calls
		find_package(PkgConfig)
		if(PKG_CONFIG_FOUND)
			pkg_check_modules(PC_${_component} ${_pkgconfig})
		endif()
	endif(NOT WIN32)

	find_path(${_component}_INCLUDE_DIRS ${_header}
		HINTS
			${PC_LIB${_component}_INCLUDEDIR}
			${PC_LIB${_component}_INCLUDE_DIRS}
			${FFMPEG_PATH}/include
		PATH_SUFFIXES ffmpeg)

	find_library(${_component}_LIBRARIES NAMES ${_library}
		HINTS
			${PC_LIB${_component}_LIBDIR}
			${PC_LIB${_component}_LIBRARY_DIRS}
			${FFMPEG_PATH}/lib)

	set(${_component}_DEFINITIONS  ${PC_${_component}_CFLAGS_OTHER} CACHE STRING "The ${_component} CFLAGS.")
	set(${_component}_VERSION ${PC_${_component}_VERSION} CACHE STRING "The ${_component} version number.")

	if(WIN32 AND NOT ${_component}_VERSION)
		file(GLOB FOUND_DLL_ ${FFMPEG_PATH}/bin/${_library}*.dll)
		string(REGEX MATCH ".*${_library}-(.+).dll" FOUND_DLL_ ${FOUND_DLL_})
		set(${_component}_VERSION ${CMAKE_MATCH_1} CACHE STRING "The ${_component} version number." FORCE)
	endif()

	set_component_found(${_component})

	mark_as_advanced(
		${_component}_INCLUDE_DIRS
		${_component}_LIBRARIES
		${_component}_DEFINITIONS
		${_component}_VERSION)
endmacro()

# Check for cached results. If there are skip the costly part.
if(NOT FFMPEG_LIBRARIES)
	# Check for all possible component.
	find_component(AVCODEC libavcodec avcodec libavcodec/avcodec.h)
	find_component(AVFORMAT libavformat avformat libavformat/avformat.h)
	find_component(AVDEVICE libavdevice avdevice libavdevice/avdevice.h)
	find_component(AVUTIL libavutil avutil libavutil/avutil.h)
	find_component(AVFILTER libavfilter avfilter libavfilter/avfilter.h)
	find_component(SWSCALE libswscale swscale libswscale/swscale.h)
	find_component(POSTPROC libpostproc postproc libpostproc/postprocess.h)
	find_component(SWRESAMPLE libswresample swresample libswresample/swresample.h)

	# Check if the required components were found and add their stuff to the FFMPEG_* vars.
	foreach(_component ${FFmpeg_FIND_COMPONENTS})
		if(${_component}_FOUND)
			# message(STATUS "Required component ${_component} present.")
			set(FFMPEG_LIBRARIES ${FFMPEG_LIBRARIES} ${${_component}_LIBRARIES})
			set(FFMPEG_DEFINITIONS ${FFMPEG_DEFINITIONS} ${${_component}_DEFINITIONS})
			list(APPEND FFMPEG_INCLUDE_DIRS ${${_component}_INCLUDE_DIRS})
		else()
			# message(STATUS "Required component ${_component} missing.")
		endif()
	endforeach()

	# Build the include path with duplicates removed.
	if(FFMPEG_INCLUDE_DIRS)
		list(REMOVE_DUPLICATES FFMPEG_INCLUDE_DIRS)
	endif()

	# cache the vars.
	set(FFMPEG_INCLUDE_DIRS ${FFMPEG_INCLUDE_DIRS} CACHE STRING "The FFmpeg include directories." FORCE)
	set(FFMPEG_LIBRARIES ${FFMPEG_LIBRARIES} CACHE STRING "The FFmpeg libraries." FORCE)
	set(FFMPEG_DEFINITIONS ${FFMPEG_DEFINITIONS} CACHE STRING "The FFmpeg cflags." FORCE)

	mark_as_advanced(
		FFMPEG_INCLUDE_DIRS
		FFMPEG_LIBRARIES
		FFMPEG_DEFINITIONS)
endif()

# Now set the noncached _FOUND vars for the components.
foreach(_component AVCODEC AVDEVICE AVFORMAT AVUTIL POSTPROCESS SWSCALE)
	set_component_found(${_component})
endforeach()

# Compile the list of required vars
set(_FFmpeg_REQUIRED_VARS FFMPEG_LIBRARIES FFMPEG_INCLUDE_DIRS)
foreach(_component ${FFmpeg_FIND_COMPONENTS})
	list(APPEND _FFmpeg_REQUIRED_VARS ${_component}_LIBRARIES ${_component}_INCLUDE_DIRS)
endforeach()

# Give a nice error message if some of the required vars are missing.
find_package_handle_standard_args(FFmpeg DEFAULT_MSG ${_FFmpeg_REQUIRED_VARS})