BUILD.gn - chromium/third_party/ffmpeg - Git at Google

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.

 import("ffmpeg_options.gni")
 import("ffmpeg_generated.gni")

 # Path to platform configuration files.
 platform_config_root =
     "chromium/config/$ffmpeg_branding/$os_config/$ffmpeg_arch"

 has_yasm_deps =
     ffmpeg_yasm_sources != [] &&
     (current_cpu == "x86" || current_cpu == "x64") && os_config != "linux-noasm"
 if (has_yasm_deps) {
   import("//third_party/yasm/yasm_assemble.gni")
   yasm_assemble("ffmpeg_yasm") {
     sources = ffmpeg_yasm_sources

     # Ensure the architecture defines go in the command line before the -P
     # file below, so don't use defines.
     yasm_flags = []
     if (current_cpu == "x86") {
       yasm_flags += [ "-DARCH_X86_32" ]
     } else if (current_cpu == "x64") {
       yasm_flags += [ "-DARCH_X86_64" ]
     }

     inputs = [
       # Sets visibility hidden for cglobal functions. Explicitly included
       # to avoid overlooking changes to this file in incremental builds.
       "libavutil/x86/x86inc.asm",
     ]

     defines = [ "PIC" ]
     include_dirs = [
       platform_config_root,
       "libavcodec/x86",
       "libavutil/x86",
       ".",
     ]

     # Disable warnings, prevents log spam for things we won't fix.
     yasm_flags += [
       "-w",
       "-P",
       rebase_path("$platform_config_root/config.asm", root_build_dir),
     ]

     if (is_mac) {
       # Necessary to ensure symbols end up with a _ prefix; added by
       # yasm_assemble.gni for Windows, but not Mac.
       defines += [ "PREFIX" ]
     }
   }
 }

 config("ffmpeg_dependent_config") {
   include_dirs = [
     platform_config_root,
     ".",
   ]
 }

 if (is_win) {
   # Stub generator script and signatures of all functions used by Chrome.
   generate_stubs_script = "//tools/generate_stubs/generate_stubs.py"

   # Used by ffmpeg_generate_stubs and ffmpeg_generate_def
   sig_files = [ "chromium/ffmpeg.sigs" ]

   action("ffmpeg_generate_def") {
     script = generate_stubs_script
     sources = sig_files
     outputs = [
       "$target_gen_dir/ffmpeg.def",
     ]
     args = [
              # TODO(ajwong): This was -i <(INTERMEDIATE_DIR). What next?
              "-i",
              rebase_path(target_out_dir, root_build_dir),
              "-o",
              rebase_path(target_gen_dir, root_build_dir),
              "-t",
              "windows_def",
              "-m",
              "ffmpeg.dll",
            ] + rebase_path(sources, root_build_dir)
   }
 }

 # gn orders flags on a target before flags from configs. The default config
 # adds -Wall, and these flags have to be after -Wall -- so they need to come
 # from a config and can't be on the target directly.
 config("ffmpegsumo_warnings") {
   if (is_clang) {
     cflags = [
       "-Wno-absolute-value",

       # ffmpeg uses its own deprecated functions.
       "-Wno-deprecated-declarations",

       # ffmpeg doesn't care about pointer constness.
       "-Wno-incompatible-pointer-types",

       # ffmpeg doesn't follow usual parentheses conventions.
       "-Wno-logical-op-parentheses",

       # ffmpeg doesn't care about pointer signedness.
       "-Wno-parentheses",

       # ffmpeg doesn't care about pointer signedness.
       "-Wno-pointer-sign",

       # ffmpeg doesn't believe in exhaustive switch statements.
       "-Wno-switch",

       # matroskadec.c has a "failed:" label that's only used if some
       # CONFIG_ flags we don't set are set.
       "-Wno-unused-label",

       # ffmpeg has a lot of unused variables.
       "-Wno-unused-variable",

       # This fires on `av_assert0(!"valid element size")` in utils.c
       "-Wno-string-conversion",

       # This fires on `pos_min` and `pos_max` in
       # autorename_libavformat_utils.c
       "-Wno-sometimes-uninitialized",

       # ffmpeg contains static functions in header files, which lead
       # to unused function warnings. There are a few legit unused
       # functions too.
       "-Wno-unused-function",

       # vp3data.h's vp31_inter_dequant stores '128' in an int8_t array.
       "-Wno-constant-conversion",
     ]
     if (is_win) {
       # This corresponds to /wd4273 below.
       cflags += [ "-Wno-inconsistent-dllimport" ]
     }
   }
 }

 if (is_component_ffmpeg) {
   link_target_type = "source_set"
 } else {
   # This must be a static_library in non-component builds to avoid pulling
   # in many large global arrays (and associated code) into chrome.dll.
   link_target_type = "static_library"
 }
 target(link_target_type, "ffmpeg_internal") {
   sources = ffmpeg_c_sources + ffmpeg_gas_sources + [
               "$platform_config_root/config.h",
               "$platform_config_root/libavutil/avconfig.h",
             ]
   include_dirs = [
     platform_config_root,
     ".",
   ]
   defines = [
     "HAVE_AV_CONFIG_H",
     "_POSIX_C_SOURCE=200112",
     "_XOPEN_SOURCE=600",
     "PIC",

     # Disable deprecated features that generate spammy warnings.
     # media/ffmpeg/ffmpeg_common.h defines these as well and must be kept
     # in sync with this file.
     "FF_API_CONVERGENCE_DURATION=0",

     # Upstream libavcodec/utils.c still uses the deprecated
     # av_dup_packet(), causing deprecation warnings.
     # The normal fix for such things is to disable the feature as below,
     # but the upstream code does not yet compile with it disabled.
     # (In this case, the fix is replacing the call with a new function.)
     # In the meantime, we directly disable those warnings in the C file.
     # "FF_API_AVPACKET_OLD_API=0",
   ]

   # So we can append below and assume they're defined.
   cflags = []
   ldflags = []
   libs = []
   deps = [
     "//third_party/opus",
   ]

   configs -= [ "//build/config/compiler:chromium_code" ]
   configs += [
     "//build/config/compiler:no_chromium_code",

     # These must be after no_chromium_code for warning flags to be ordered
     # correctly.
     "//build/config/compiler:no_incompatible_pointer_warnings",
     ":ffmpegsumo_warnings",
   ]

   # Since we are not often debugging FFmpeg, and performance is
   # unacceptable without optimization, freeze the optimizations to -O2.
   # If someone really wants -O1 , they can change these in their checkout.
   # If you want -O0, see the Gotchas in README.Chromium for why that
   # won't work.
   #
   # In addition to the above reasons, /Od optimization won't remove symbols
   # that are under "if (0)" style sections.  Which lead to link time errors
   # when for example it tries to link an ARM symbol on X86.
   configs -= [ "//build/config/compiler:default_optimization" ]
   if (is_win) {
     # Setting the optimizations to 'speed' or to 'max' on Windows results in
     # a lot of unresolved symbols. The only supported mode is 'size' (see
     # crbug.com/264459).
     #
     # FFMmpeg require dead code elimination to be available in all build modes
     # and thus doesn't support wpo.
     configs += [ "//build/config/compiler:optimize_no_wpo" ]
   } else {
     configs += [ "//build/config/compiler:optimize_max" ]
   }

   if (is_posix) {
     # Remove default stack frames config so we can force -fomit-frame-pointer.
     configs -= [ "//build/config/compiler:default_stack_frames" ]

     cflags += [
       "-fPIC",
       "-fomit-frame-pointer",

       # ffmpeg uses its own deprecated functions.
       "-Wno-deprecated-declarations",
     ]

     if (!is_clang) {
       # gcc doesn't have flags for specific warnings, so disable them
       # all.
       cflags += [ "-w" ]
     }

     if (current_cpu == "arm" || current_cpu == "arm64") {
       asmflags = []
       if (arm_float_abi == "hard") {
         asmflags += [ "-DHAVE_VFP_ARGS=1" ]
       } else {
         asmflags += [ "-DHAVE_VFP_ARGS=0" ]
       }
       if (is_clang) {
         # TODO(hans) Enable integrated-as (crbug.com/124610).
         asmflags += [ "-fno-integrated-as" ]
         if (is_android) {
           import("//build/config/android/config.gni")
           rebased_android_toolchain_root =
               rebase_path(android_toolchain_root, root_build_dir)

           # Else /usr/bin/as gets picked up.
           asmflags += [ "-B${rebased_android_toolchain_root}/bin" ]
         }
       }
     }
   }

   if (is_posix && !is_mac) {
     defines += [
       "_ISOC99_SOURCE",
       "_LARGEFILE_SOURCE",

       # BUG(ihf): ffmpeg compiles with this define. But according to
       # ajwong: I wouldn't change _FILE_OFFSET_BITS.  That's a scary change
       # cause it affects the default length of off_t, and fpos_t,
       # which can cause strange problems if the loading code doesn't
       # have it set and you start passing FILE*s or file descriptors
       # between symbol contexts.
       # "_FILE_OFFSET_BITS=64",
     ]
     cflags += [
       "-std=c99",
       "-pthread",
       "-fno-math-errno",
       "-fno-signed-zeros",
       "-fno-tree-vectorize",
       "-fomit-frame-pointer",
     ]
     ldflags = [
       "-L",
       rebase_path(target_gen_dir, root_build_dir),
     ]
     if (!is_android) {
       # OS=android requires that both -lz and -lm occur after
       # -lc++_shared on the link command line. Android link rules
       # already include -lm, and we get -lz as a transitive dependency
       # of libandroid.so, so simply moving both to the non-Android
       # section solves the problem.
       #
       # The root cause of this problem is certain system libraries
       # (libm starting with MNC and libz before MNC, among others)
       # re-export the libgcc unwinder, and libc++ exports the
       # libc++abi unwinder. As we build against libc++ headers, libc++
       # must be the first in the runtime symbol lookup order (among
       # all unwinder-providing libraries).

       # librt for clock_gettime on precise
       libs += [
         "m",
         "z",
         "rt",
       ]
     }
     if (is_component_ffmpeg) {
       # Export all symbols when building as component.
       configs -= [ "//build/config/gcc:symbol_visibility_hidden" ]
       configs += [ "//build/config/gcc:symbol_visibility_default" ]
     }

     # TODO(ajwong): How to handle openbsd? Especially w/o the is_posix?
     #      if (is_openbsd) {
     #       # OpenBSD's gcc (4.2.1) does not support this flag
     #       cflags -= [ "-fno-signed-zeros" ]
     #      }
   }
   if (is_mac) {
     if (is_component_ffmpeg) {
       # Export all symbols when building as component.
       configs -= [ "//build/config/gcc:symbol_visibility_hidden" ]
       configs += [ "//build/config/gcc:symbol_visibility_default" ]
     }

     defines += [ "_DARWIN_C_SOURCE" ]
   } else if (is_win) {
     import("//build/config/win/visual_studio_version.gni")

     if (visual_studio_version == "2013" || visual_studio_version == "2013e") {
       defines += [
         # VS 2015 supports these natively so they cannot be #defines.
         "inline=__inline",
         "strtoll=_strtoi64",
         "strtod=avpriv_strtod",
         "snprintf=avpriv_snprintf",
         "vsnprintf=avpriv_vsnprintf",

         # This leads to duplicate avpriv_snprintf definitions due to inline
         # _snprintf in VC++ 2015 stdio.h.
         "_snprintf=avpriv_snprintf",
       ]
     }
     defines += [
       "_ISOC99_SOURCE",
       "_LARGEFILE_SOURCE",
       "HAVE_AV_CONFIG_H",
     ]

     if (is_component_ffmpeg) {
       # Required to avoid 4049 and 4217 errors around redundant imports.
       cflags += [
         "/FIcompat/msvcrt/snprintf.h",
         "/FIcompat/msvcrt/strtod.h",
       ]
     }

     # TODO(dalecurtis): We should fix these.  http://crbug.com/154421
     cflags += [
       "/wd4996",  # 'function': was declared deprecated
       "/wd4018",  # 'expression': signed/unsigned mismatch
       "/wd4090",  # 'operation' : different 'modifier' qualifiers
       "/wd4305",  # 'identifier': truncation from 'type1' to 'type2'
       "/wd4133",  # 'type' : incompatible types - from 'type1' to 'type2'
       "/wd4146",  # unary minus operator applied to unsigned type, result
                   #   still unsigned

       "/wd4554",  # 'operator' : check operator precedence for possible
                   #   error; use parentheses to clarify precedence

       "/wd4028",  # formal parameter 'number' different from declaration
       "/wd4334",  # 'operator' : result of 32-bit shift implicitly
                   #   converted to 64 bits (was 64-bit shift intended?)

       "/wd4101",  # 'identifier' : unreferenced local variable
       "/wd4102",  # 'label' : unreferenced label
       "/wd4116",  # unnamed type definition in parentheses
       "/wd4307",  # 'operator' : integral constant overflow
       "/wd4273",  # 'function' : inconsistent DLL linkage
       "/wd4005",  # 'identifier' : macro redefinition
       "/wd4056",  # overflow in floating point constant arithmetic
       "/wd4756",  # overflow in constant arithmetic
     ]
     if (current_cpu == "x64") {
       # TODO(wolenetz): We should fix this.  http://crbug.com/171009
       cflags += [ "/wd4267" ]  # Conversion from size_t to 'type'.
     }
   }

   if (has_yasm_deps) {
     deps += [ ":ffmpeg_yasm" ]
   }
 }

 if (is_component_ffmpeg) {
   shared_library("ffmpeg") {
     public_configs = [ ":ffmpeg_dependent_config" ]
     deps = [
       ":ffmpeg_internal",
     ]

     # So we can append below and assume they're defined.
     ldflags = []

     if (is_posix && !is_mac) {
       # Fixes warnings PIC relocation when building as component.
       ldflags += [
         "-Wl,-Bsymbolic",
         "-L",
         rebase_path(target_gen_dir, root_build_dir),
       ]
     } else if (is_win) {
       # Windows component build needs the .def file to export ffmpeg symbols.
       deps += [ ":ffmpeg_generate_def" ]
       sources = [
         "$target_gen_dir/ffmpeg.def",
       ]
     }
   }
 } else {
   source_set("ffmpeg") {
     public_configs = [ ":ffmpeg_dependent_config" ]
     deps = [
       ":ffmpeg_internal",
     ]
   }
 }
	# Copyright 2014 The Chromium Authors. All rights reserved.
	# Use of this source code is governed by a BSD-style license that can be
	# found in the LICENSE file.

	import("ffmpeg_options.gni")
	import("ffmpeg_generated.gni")

	# Path to platform configuration files.
	platform_config_root =
	"chromium/config/$ffmpeg_branding/$os_config/$ffmpeg_arch"

	has_yasm_deps =
	ffmpeg_yasm_sources != [] &&
	(current_cpu == "x86" \|\| current_cpu == "x64") && os_config != "linux-noasm"
	if (has_yasm_deps) {
	import("//third_party/yasm/yasm_assemble.gni")
	yasm_assemble("ffmpeg_yasm") {
	sources = ffmpeg_yasm_sources

	# Ensure the architecture defines go in the command line before the -P
	# file below, so don't use defines.
	yasm_flags = []
	if (current_cpu == "x86") {
	yasm_flags += [ "-DARCH_X86_32" ]
	} else if (current_cpu == "x64") {
	yasm_flags += [ "-DARCH_X86_64" ]
	}

	inputs = [
	# Sets visibility hidden for cglobal functions. Explicitly included
	# to avoid overlooking changes to this file in incremental builds.
	"libavutil/x86/x86inc.asm",
	]

	defines = [ "PIC" ]
	include_dirs = [
	platform_config_root,
	"libavcodec/x86",
	"libavutil/x86",
	".",
	]

	# Disable warnings, prevents log spam for things we won't fix.
	yasm_flags += [
	"-w",
	"-P",
	rebase_path("$platform_config_root/config.asm", root_build_dir),
	]

	if (is_mac) {
	# Necessary to ensure symbols end up with a _ prefix; added by
	# yasm_assemble.gni for Windows, but not Mac.
	defines += [ "PREFIX" ]
	}
	}
	}

	config("ffmpeg_dependent_config") {
	include_dirs = [
	platform_config_root,
	".",
	]
	}

	if (is_win) {
	# Stub generator script and signatures of all functions used by Chrome.
	generate_stubs_script = "//tools/generate_stubs/generate_stubs.py"

	# Used by ffmpeg_generate_stubs and ffmpeg_generate_def
	sig_files = [ "chromium/ffmpeg.sigs" ]

	action("ffmpeg_generate_def") {
	script = generate_stubs_script
	sources = sig_files
	outputs = [
	"$target_gen_dir/ffmpeg.def",
	]
	args = [
	# TODO(ajwong): This was -i <(INTERMEDIATE_DIR). What next?
	"-i",
	rebase_path(target_out_dir, root_build_dir),
	"-o",
	rebase_path(target_gen_dir, root_build_dir),
	"-t",
	"windows_def",
	"-m",
	"ffmpeg.dll",
	] + rebase_path(sources, root_build_dir)
	}
	}

	# gn orders flags on a target before flags from configs. The default config
	# adds -Wall, and these flags have to be after -Wall -- so they need to come
	# from a config and can't be on the target directly.
	config("ffmpegsumo_warnings") {
	if (is_clang) {
	cflags = [
	"-Wno-absolute-value",

	# ffmpeg uses its own deprecated functions.
	"-Wno-deprecated-declarations",

	# ffmpeg doesn't care about pointer constness.
	"-Wno-incompatible-pointer-types",

	# ffmpeg doesn't follow usual parentheses conventions.
	"-Wno-logical-op-parentheses",

	# ffmpeg doesn't care about pointer signedness.
	"-Wno-parentheses",

	# ffmpeg doesn't care about pointer signedness.
	"-Wno-pointer-sign",

	# ffmpeg doesn't believe in exhaustive switch statements.
	"-Wno-switch",

	# matroskadec.c has a "failed:" label that's only used if some
	# CONFIG_ flags we don't set are set.
	"-Wno-unused-label",

	# ffmpeg has a lot of unused variables.
	"-Wno-unused-variable",

	# This fires on `av_assert0(!"valid element size")` in utils.c
	"-Wno-string-conversion",

	# This fires on `pos_min` and `pos_max` in
	# autorename_libavformat_utils.c
	"-Wno-sometimes-uninitialized",

	# ffmpeg contains static functions in header files, which lead
	# to unused function warnings. There are a few legit unused
	# functions too.
	"-Wno-unused-function",

	# vp3data.h's vp31_inter_dequant stores '128' in an int8_t array.
	"-Wno-constant-conversion",
	]
	if (is_win) {
	# This corresponds to /wd4273 below.
	cflags += [ "-Wno-inconsistent-dllimport" ]
	}
	}
	}

	if (is_component_ffmpeg) {
	link_target_type = "source_set"
	} else {
	# This must be a static_library in non-component builds to avoid pulling
	# in many large global arrays (and associated code) into chrome.dll.
	link_target_type = "static_library"
	}
	target(link_target_type, "ffmpeg_internal") {
	sources = ffmpeg_c_sources + ffmpeg_gas_sources + [
	"$platform_config_root/config.h",
	"$platform_config_root/libavutil/avconfig.h",
	]
	include_dirs = [
	platform_config_root,
	".",
	]
	defines = [
	"HAVE_AV_CONFIG_H",
	"_POSIX_C_SOURCE=200112",
	"_XOPEN_SOURCE=600",
	"PIC",

	# Disable deprecated features that generate spammy warnings.
	# media/ffmpeg/ffmpeg_common.h defines these as well and must be kept
	# in sync with this file.
	"FF_API_CONVERGENCE_DURATION=0",

	# Upstream libavcodec/utils.c still uses the deprecated
	# av_dup_packet(), causing deprecation warnings.
	# The normal fix for such things is to disable the feature as below,
	# but the upstream code does not yet compile with it disabled.
	# (In this case, the fix is replacing the call with a new function.)
	# In the meantime, we directly disable those warnings in the C file.
	# "FF_API_AVPACKET_OLD_API=0",
	]

	# So we can append below and assume they're defined.
	cflags = []
	ldflags = []
	libs = []
	deps = [
	"//third_party/opus",
	]

	configs -= [ "//build/config/compiler:chromium_code" ]
	configs += [
	"//build/config/compiler:no_chromium_code",

	# These must be after no_chromium_code for warning flags to be ordered
	# correctly.
	"//build/config/compiler:no_incompatible_pointer_warnings",
	":ffmpegsumo_warnings",
	]

	# Since we are not often debugging FFmpeg, and performance is
	# unacceptable without optimization, freeze the optimizations to -O2.
	# If someone really wants -O1 , they can change these in their checkout.
	# If you want -O0, see the Gotchas in README.Chromium for why that
	# won't work.
	#
	# In addition to the above reasons, /Od optimization won't remove symbols
	# that are under "if (0)" style sections. Which lead to link time errors
	# when for example it tries to link an ARM symbol on X86.
	configs -= [ "//build/config/compiler:default_optimization" ]
	if (is_win) {
	# Setting the optimizations to 'speed' or to 'max' on Windows results in
	# a lot of unresolved symbols. The only supported mode is 'size' (see
	# crbug.com/264459).
	#
	# FFMmpeg require dead code elimination to be available in all build modes
	# and thus doesn't support wpo.
	configs += [ "//build/config/compiler:optimize_no_wpo" ]
	} else {
	configs += [ "//build/config/compiler:optimize_max" ]
	}

	if (is_posix) {
	# Remove default stack frames config so we can force -fomit-frame-pointer.
	configs -= [ "//build/config/compiler:default_stack_frames" ]

	cflags += [
	"-fPIC",
	"-fomit-frame-pointer",

	# ffmpeg uses its own deprecated functions.
	"-Wno-deprecated-declarations",
	]

	if (!is_clang) {
	# gcc doesn't have flags for specific warnings, so disable them
	# all.
	cflags += [ "-w" ]
	}

	if (current_cpu == "arm" \|\| current_cpu == "arm64") {
	asmflags = []
	if (arm_float_abi == "hard") {
	asmflags += [ "-DHAVE_VFP_ARGS=1" ]
	} else {
	asmflags += [ "-DHAVE_VFP_ARGS=0" ]
	}
	if (is_clang) {
	# TODO(hans) Enable integrated-as (crbug.com/124610).
	asmflags += [ "-fno-integrated-as" ]
	if (is_android) {
	import("//build/config/android/config.gni")
	rebased_android_toolchain_root =
	rebase_path(android_toolchain_root, root_build_dir)

	# Else /usr/bin/as gets picked up.
	asmflags += [ "-B${rebased_android_toolchain_root}/bin" ]
	}
	}
	}
	}

	if (is_posix && !is_mac) {
	defines += [
	"_ISOC99_SOURCE",
	"_LARGEFILE_SOURCE",

	# BUG(ihf): ffmpeg compiles with this define. But according to
	# ajwong: I wouldn't change _FILE_OFFSET_BITS. That's a scary change
	# cause it affects the default length of off_t, and fpos_t,
	# which can cause strange problems if the loading code doesn't
	# have it set and you start passing FILE*s or file descriptors
	# between symbol contexts.
	# "_FILE_OFFSET_BITS=64",
	]
	cflags += [
	"-std=c99",
	"-pthread",
	"-fno-math-errno",
	"-fno-signed-zeros",
	"-fno-tree-vectorize",
	"-fomit-frame-pointer",
	]
	ldflags = [
	"-L",
	rebase_path(target_gen_dir, root_build_dir),
	]
	if (!is_android) {
	# OS=android requires that both -lz and -lm occur after
	# -lc++_shared on the link command line. Android link rules
	# already include -lm, and we get -lz as a transitive dependency
	# of libandroid.so, so simply moving both to the non-Android
	# section solves the problem.
	#
	# The root cause of this problem is certain system libraries
	# (libm starting with MNC and libz before MNC, among others)
	# re-export the libgcc unwinder, and libc++ exports the
	# libc++abi unwinder. As we build against libc++ headers, libc++
	# must be the first in the runtime symbol lookup order (among
	# all unwinder-providing libraries).

	# librt for clock_gettime on precise
	libs += [
	"m",
	"z",
	"rt",
	]
	}
	if (is_component_ffmpeg) {
	# Export all symbols when building as component.
	configs -= [ "//build/config/gcc:symbol_visibility_hidden" ]
	configs += [ "//build/config/gcc:symbol_visibility_default" ]
	}

	# TODO(ajwong): How to handle openbsd? Especially w/o the is_posix?
	# if (is_openbsd) {
	# # OpenBSD's gcc (4.2.1) does not support this flag
	# cflags -= [ "-fno-signed-zeros" ]
	# }
	}
	if (is_mac) {
	if (is_component_ffmpeg) {
	# Export all symbols when building as component.
	configs -= [ "//build/config/gcc:symbol_visibility_hidden" ]
	configs += [ "//build/config/gcc:symbol_visibility_default" ]
	}

	defines += [ "_DARWIN_C_SOURCE" ]
	} else if (is_win) {
	import("//build/config/win/visual_studio_version.gni")

	if (visual_studio_version == "2013" \|\| visual_studio_version == "2013e") {
	defines += [
	# VS 2015 supports these natively so they cannot be #defines.
	"inline=__inline",
	"strtoll=_strtoi64",
	"strtod=avpriv_strtod",
	"snprintf=avpriv_snprintf",
	"vsnprintf=avpriv_vsnprintf",

	# This leads to duplicate avpriv_snprintf definitions due to inline
	# _snprintf in VC++ 2015 stdio.h.
	"_snprintf=avpriv_snprintf",
	]
	}
	defines += [
	"_ISOC99_SOURCE",
	"_LARGEFILE_SOURCE",
	"HAVE_AV_CONFIG_H",
	]

	if (is_component_ffmpeg) {
	# Required to avoid 4049 and 4217 errors around redundant imports.
	cflags += [
	"/FIcompat/msvcrt/snprintf.h",
	"/FIcompat/msvcrt/strtod.h",
	]
	}

	# TODO(dalecurtis): We should fix these. http://crbug.com/154421
	cflags += [
	"/wd4996", # 'function': was declared deprecated
	"/wd4018", # 'expression': signed/unsigned mismatch
	"/wd4090", # 'operation' : different 'modifier' qualifiers
	"/wd4305", # 'identifier': truncation from 'type1' to 'type2'
	"/wd4133", # 'type' : incompatible types - from 'type1' to 'type2'
	"/wd4146", # unary minus operator applied to unsigned type, result
	# still unsigned

	"/wd4554", # 'operator' : check operator precedence for possible
	# error; use parentheses to clarify precedence

	"/wd4028", # formal parameter 'number' different from declaration
	"/wd4334", # 'operator' : result of 32-bit shift implicitly
	# converted to 64 bits (was 64-bit shift intended?)

	"/wd4101", # 'identifier' : unreferenced local variable
	"/wd4102", # 'label' : unreferenced label
	"/wd4116", # unnamed type definition in parentheses
	"/wd4307", # 'operator' : integral constant overflow
	"/wd4273", # 'function' : inconsistent DLL linkage
	"/wd4005", # 'identifier' : macro redefinition
	"/wd4056", # overflow in floating point constant arithmetic
	"/wd4756", # overflow in constant arithmetic
	]
	if (current_cpu == "x64") {
	# TODO(wolenetz): We should fix this. http://crbug.com/171009
	cflags += [ "/wd4267" ] # Conversion from size_t to 'type'.
	}
	}

	if (has_yasm_deps) {
	deps += [ ":ffmpeg_yasm" ]
	}
	}

	if (is_component_ffmpeg) {
	shared_library("ffmpeg") {
	public_configs = [ ":ffmpeg_dependent_config" ]
	deps = [
	":ffmpeg_internal",
	]

	# So we can append below and assume they're defined.
	ldflags = []

	if (is_posix && !is_mac) {
	# Fixes warnings PIC relocation when building as component.
	ldflags += [
	"-Wl,-Bsymbolic",
	"-L",
	rebase_path(target_gen_dir, root_build_dir),
	]
	} else if (is_win) {
	# Windows component build needs the .def file to export ffmpeg symbols.
	deps += [ ":ffmpeg_generate_def" ]
	sources = [
	"$target_gen_dir/ffmpeg.def",
	]
	}
	}
	} else {
	source_set("ffmpeg") {
	public_configs = [ ":ffmpeg_dependent_config" ]
	deps = [
	":ffmpeg_internal",
	]
	}
	}