Build Windows CPU wheel (#753)

Author: NicolasHug

.github/workflows/windows_wheel.yaml

@@ -0,0 +1,62 @@
+name: Build and test Windows wheel
+
+on:
+  pull_request:
+  push:
+    branches:
+      - nightly
+      - main
+      - release/*
+    tags:
+        - v[0-9]+.[0-9]+.[0-9]+-rc[0-9]+
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref_name }}-${{ github.ref_type == 'branch' && github.sha }}-${{ github.event_name == 'workflow_dispatch' }}
+  cancel-in-progress: true
+
+permissions:
+  id-token: write
+  contents: write
+
+defaults:
+  run:
+    shell: bash -l -eo pipefail {0}
+
+jobs:
+
+  generate-matrix:
+    uses: pytorch/test-infra/.github/workflows/generate_binary_build_matrix.yml@main
+    with:
+      package-type: wheel
+      os: windows
+      test-infra-repository: pytorch/test-infra
+      test-infra-ref: main
+      with-xpu: disable
+      with-rocm: disable
+      with-cuda: disable
+      build-python-only: "disable"
+
+  build:
+    needs: generate-matrix
+    strategy:
+      fail-fast: false
+    name: Build and Upload Windows wheel
+    # TODO: use @main
+    uses: nicolashug/test-infra/.github/workflows/build_wheels_windows.yml@build-platform-windows
+    with:
+      repository: pytorch/torchcodec
+      ref: ""
+      test-infra-repository: nicolashug/test-infra
+      test-infra-ref: build-platform-windows
+      build-matrix: ${{ needs.generate-matrix.outputs.matrix }}
+      pre-script: packaging/pre_build_script.sh
+      # post-script: packaging/post_build_script.sh  TODO: consider enabling post-build checks for Windows
+      env-script: packaging/vc_env_helper.bat
+      smoke-test-script: packaging/fake_smoke_test.py
+      package-name: torchcodec
+      trigger-event: ${{ github.event_name }}
+      build-platform: "python-build-package"
+      # The BUILD_AGAINST_ALL_FFMPEG_FROM_S3 var, needed to build the wheel, is
+      # set in vc_env_helper.bat Couldn't find a way to set it from here.
+      build-command: "python -m build --wheel -vvv --no-isolation"

packaging/vc_env_helper.bat

@@ -24,6 +24,7 @@ if "%VSDEVCMD_ARGS%" == "" (
 if "%CU_VERSION%" == "xpu" call "C:\Program Files (x86)\Intel\oneAPI\setvars.bat"
 
 set DISTUTILS_USE_SDK=1
+set BUILD_AGAINST_ALL_FFMPEG_FROM_S3=1
 
 set args=%1
 shift

setup.py

@@ -155,10 +155,10 @@ def copy_extensions_to_source(self):
             # dynamically loaded module. For more, see:
             #   https://stackoverflow.com/a/2339910
             extensions = ["dylib", "so"]
+        elif sys.platform in ("win32", "cygwin"):
+            extensions = ["dll"]
         else:
-            raise NotImplementedError(
-                "Platforms other than linux/darwin are not supported yet"
-            )
+            raise NotImplementedError(f"Platform {sys.platform} is not supported")
 
         for ext in extensions:
             for lib_file in self._install_prefix.glob(f"*.{ext}"):

src/torchcodec/_core/CMakeLists.txt

@@ -11,10 +11,29 @@ find_package(Python3 ${PYTHON_VERSION} EXACT COMPONENTS Development)
 if(DEFINED TORCHCODEC_DISABLE_COMPILE_WARNING_AS_ERROR AND TORCHCODEC_DISABLE_COMPILE_WARNING_AS_ERROR)
     set(TORCHCODEC_WERROR_OPTION "")
 else()
-    set(TORCHCODEC_WERROR_OPTION "-Werror")
+    if (WIN32)
+        # TODO set warnings as errors on Windows as well.
+        # set(TORCHCODEC_WERROR_OPTION "/WX")
+    else()
+        set(TORCHCODEC_WERROR_OPTION "-Werror")
+    endif()
+endif()
+
+if (WIN32)
+  # Avoid warnings about non-ASCII characters in source files.
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /wd4819")
+  # Important for when we add Windows CUDA: exporting all symbols is limited to
+  # 65535 symbols, which (apparently) will not work for CUDA.
+  # https://github.com/pytorch/pytorch/pull/3650
+  set(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS ON)
+endif()
+
+if (WIN32)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W4 ${TORCHCODEC_WERROR_OPTION} ${TORCH_CXX_FLAGS}")
+else()
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -pedantic ${TORCHCODEC_WERROR_OPTION} ${TORCH_CXX_FLAGS}")
 endif()
 
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -pedantic ${TORCHCODEC_WERROR_OPTION} ${TORCH_CXX_FLAGS}")
 
 function(make_torchcodec_sublibrary
     library_name
@@ -34,11 +53,26 @@ function(make_torchcodec_sublibrary
     # Avoid adding the "lib" prefix which we already add explicitly.
     set_target_properties(${library_name} PROPERTIES PREFIX "")
 
+    if(WIN32)
+        # On Windows, the built artifacts are put in Release/Debug
+        # subdirectories by default. We want to avoid that, otherwise our
+        # install() step would not know where to find those.
+        set_target_properties(${library_name} PROPERTIES
+            RUNTIME_OUTPUT_DIRECTORY_DEBUG ${CMAKE_CURRENT_BINARY_DIR}
+            RUNTIME_OUTPUT_DIRECTORY_RELEASE ${CMAKE_CURRENT_BINARY_DIR}
+            LIBRARY_OUTPUT_DIRECTORY_DEBUG ${CMAKE_CURRENT_BINARY_DIR}
+            LIBRARY_OUTPUT_DIRECTORY_RELEASE ${CMAKE_CURRENT_BINARY_DIR}
+            ARCHIVE_OUTPUT_DIRECTORY_DEBUG ${CMAKE_CURRENT_BINARY_DIR}
+            ARCHIVE_OUTPUT_DIRECTORY_RELEASE ${CMAKE_CURRENT_BINARY_DIR}
+        )
+    endif()
+
     target_link_libraries(
         ${library_name}
         PUBLIC
         ${library_dependencies}
     )
+
 endfunction()
 
 function(make_torchcodec_libraries
@@ -144,11 +178,14 @@ function(make_torchcodec_libraries
     # stray initialization of py::objects. The rest of the object code must
     # match. See:
     #   https://pybind11.readthedocs.io/en/stable/faq.html#someclass-declared-with-greater-visibility-than-the-type-of-its-field-someclass-member-wattributes
-    target_compile_options(
-        ${pybind_ops_library_name}
-        PUBLIC
-      "-fvisibility=hidden"
-    )
+    if(NOT WIN32)
+        target_compile_options(
+            ${pybind_ops_library_name}
+            PUBLIC
+            "-fvisibility=hidden"
+        )
+    endif()
+
     # The value we use here must match the value we return from
     # _get_pybind_ops_module_name() on the Python side. If the values do not
     # match, then we will be unable to import the C++ shared library as a
@@ -158,14 +195,17 @@ function(make_torchcodec_libraries
         PRIVATE
         PYBIND_OPS_MODULE_NAME=core_pybind_ops
     )
-    # If we don't make sure this flag is set, we run into segfauls at import
-    # time on Mac. See:
-    #    https://github.com/pybind/pybind11/issues/3907#issuecomment-1170412764
-    target_link_options(
-        ${pybind_ops_library_name}
-        PUBLIC
-        "LINKER:-undefined,dynamic_lookup"
-    )
+
+    if(APPLE)
+        # If we don't make sure this flag is set, we run into segfauls at import
+        # time on Mac. See:
+        # https://github.com/pybind/pybind11/issues/3907#issuecomment-1170412764
+        target_link_options(
+            ${pybind_ops_library_name}
+            PUBLIC
+            "LINKER:-undefined,dynamic_lookup"
+        )
+    endif()
 
     # Install all libraries.
     set(
@@ -183,7 +223,9 @@ function(make_torchcodec_libraries
     install(
         TARGETS ${all_libraries}
         LIBRARY DESTINATION ${CMAKE_INSTALL_PREFIX}
+        RUNTIME DESTINATION ${CMAKE_INSTALL_PREFIX}  # For Windows DLLs
     )
+
 endfunction()
 
 if(DEFINED ENV{BUILD_AGAINST_ALL_FFMPEG_FROM_S3})

src/torchcodec/_core/fetch_and_expose_non_gpl_ffmpeg_libs.cmake

@@ -9,12 +9,20 @@ endif()
 
 include(FetchContent)
 
+if (UNIX AND NOT APPLE)
+    set(LINUX TRUE)
+else()
+    set(LINUX FALSE)
+endif()
+
 set(
     base_url
     https://pytorch.s3.amazonaws.com/torchcodec/ffmpeg/2025-03-14
 )
 
-if (${CMAKE_SYSTEM_NAME} STREQUAL "Linux")
+if (LINUX)
+    set(lib_dir "lib")
+
     set(
         platform_url
         ${base_url}/linux_x86_64
@@ -36,7 +44,6 @@ if (${CMAKE_SYSTEM_NAME} STREQUAL "Linux")
         f7_sha256
         1cb946d8b7c6393c2c3ebe1f900b8de7a2885fe614c45d4ec32c9833084f2f26
     )
-
     set(
        f4_library_file_names
        libavutil.so.56
@@ -77,7 +84,8 @@ if (${CMAKE_SYSTEM_NAME} STREQUAL "Linux")
        libswscale.so.8
        libswresample.so.5
     )
-elseif (${CMAKE_SYSTEM_NAME} STREQUAL "Darwin")
+elseif (APPLE)
+    set(lib_dir "lib")
     set(
         platform_url
         ${base_url}/macos_arm64
@@ -98,6 +106,7 @@ elseif (${CMAKE_SYSTEM_NAME} STREQUAL "Darwin")
         f7_sha256
         48a4fc8ce098305cfd4a58f40889249c523ca3c285f66ba704b5bad0e3ada53a
     )
+
     set(
        f4_library_file_names
        libavutil.56.dylib
@@ -138,6 +147,70 @@ elseif (${CMAKE_SYSTEM_NAME} STREQUAL "Darwin")
        libswscale.8.dylib
        libswresample.5.dylib
     )
+
+elseif (WIN32)
+    set(lib_dir "bin")
+    set(
+        platform_url
+        ${base_url}/windows_x86_64
+    )
+    set(
+        f4_sha256
+        270a1aa8892225267e68a7eb87c417931da30dccbf08ee2bde8833e659cab5cb
+    )
+    set(
+        f5_sha256
+        b8b2a349a847e56a6da875b066dff1cae53cb8ee7cf5ba9321ec1243dea0cde0
+    )
+    set(
+        f6_sha256
+        5d9f8c76dc55f790fa31d825985e9270bf9e498b8bfec21a0ad3a1feb1fa053a
+    )
+    set(
+        f7_sha256
+        ae391ace382330e912793b70b68529ee7c91026d2869b4df7e7c3e7d3656bdd5
+    )
+
+    set(
+        f4_library_file_names
+        avutil.lib
+        avcodec.lib
+        avformat.lib
+        avdevice.lib
+        avfilter.lib
+        swscale.lib
+        swresample.lib
+    )
+    set(
+        f5_library_file_names
+        avutil.lib
+        avcodec.lib
+        avformat.lib
+        avdevice.lib
+        avfilter.lib
+        swscale.lib
+        swresample.lib
+    )
+    set(
+        f6_library_file_names
+        avutil.lib
+        avcodec.lib
+        avformat.lib
+        avdevice.lib
+        avfilter.lib
+        swscale.lib
+        swresample.lib
+    )
+    set(
+        f7_library_file_names
+        avutil.lib
+        avcodec.lib
+        avformat.lib
+        avdevice.lib
+        avfilter.lib
+        swscale.lib
+        swresample.lib
+    )
 else()
     message(
         FATAL_ERROR
@@ -183,24 +256,25 @@ target_include_directories(ffmpeg5 INTERFACE ${f5_SOURCE_DIR}/include)
 target_include_directories(ffmpeg6 INTERFACE ${f6_SOURCE_DIR}/include)
 target_include_directories(ffmpeg7 INTERFACE ${f7_SOURCE_DIR}/include)
 
+
 list(
     TRANSFORM f4_library_file_names
-    PREPEND ${f4_SOURCE_DIR}/lib/
+    PREPEND ${f4_SOURCE_DIR}/${lib_dir}/
     OUTPUT_VARIABLE f4_library_paths
 )
 list(
     TRANSFORM f5_library_file_names
-    PREPEND ${f5_SOURCE_DIR}/lib/
+    PREPEND ${f5_SOURCE_DIR}/${lib_dir}/
     OUTPUT_VARIABLE f5_library_paths
 )
 list(
     TRANSFORM f6_library_file_names
-    PREPEND ${f6_SOURCE_DIR}/lib/
+    PREPEND ${f6_SOURCE_DIR}/${lib_dir}/
     OUTPUT_VARIABLE f6_library_paths
 )
 list(
     TRANSFORM f7_library_file_names
-    PREPEND ${f7_SOURCE_DIR}/lib/
+    PREPEND ${f7_SOURCE_DIR}/${lib_dir}/
     OUTPUT_VARIABLE f7_library_paths
 )
 

src/torchcodec/_internally_replaced_utils.py

@@ -18,10 +18,10 @@ def _get_extension_path(lib_name: str) -> str:
         extension_suffixes = importlib.machinery.EXTENSION_SUFFIXES
     elif sys.platform == "darwin":
         extension_suffixes = importlib.machinery.EXTENSION_SUFFIXES + [".dylib"]
+    elif sys.platform in ("win32", "cygwin"):
+        extension_suffixes = importlib.machinery.EXTENSION_SUFFIXES + [".dll"]
     else:
-        raise NotImplementedError(
-            "Platforms other than linux/darwin are not supported yet"
-        )
+        raise NotImplementedError(f"{sys.platform = } is not not supported")
     loader_details = (
         importlib.machinery.ExtensionFileLoader,
         extension_suffixes,