build(windows): add arm64 build

.github/workflows/ci.yml

@@ -68,6 +68,15 @@ jobs:
             arch: x86_64
             generator: "MSYS Makefiles"
             shell: msys2 {0}
+            msystem: ucrt64
+            toolchain: ucrt-x86_64
+          - name: Windows-ARM64
+            os: windows-11-arm
+            arch: aarch64
+            generator: "MSYS Makefiles"
+            shell: msys2 {0}
+            msystem: clangarm64
+            toolchain: clang-aarch64
     defaults:
       run:
         shell: ${{ matrix.shell }}
@@ -269,21 +278,23 @@ jobs:
         if: runner.os == 'Windows'
         uses: msys2/setup-msys2@v2
         with:
-          msystem: ucrt64
+          msystem: ${{ matrix.msystem }}
           update: true
 
       - name: Update Windows dependencies
         env:
-          MSYSTEM: ucrt64
-          TOOLCHAIN: ucrt-x86_64
+          MSYSTEM: ${{ matrix.msystem }}
+          TOOLCHAIN: ${{ matrix.toolchain }}
         if: runner.os == 'Windows'
         shell: msys2 {0}
         run: |
           # variables
           declare -A pinned_deps
           pinned_deps["mingw-w64-${TOOLCHAIN}-cmake"]="3.31.6-1"
-          pinned_deps["mingw-w64-${TOOLCHAIN}-gcc"]="14.2.0-3"
-          pinned_deps["mingw-w64-${TOOLCHAIN}-gcc-libs"]="14.2.0-3"
+          if [[ ${MSYSTEM} == "ucrt64" ]]; then
+            pinned_deps["mingw-w64-${TOOLCHAIN}-gcc"]="14.2.0-3"
+            pinned_deps["mingw-w64-${TOOLCHAIN}-gcc-libs"]="14.2.0-3"
+          fi
 
           dependencies=(
             "diffutils"
@@ -331,7 +342,8 @@ jobs:
       - name: Debug msys2.CMD
         if: runner.os == 'Windows'
         run: |
-          cat /d/a/_temp/setup-msys2/msys2.CMD
+          echo "MSYS2_ROOT=${{ runner.temp }}/msys64" >> $GITHUB_ENV
+          cat "${{ runner.temp }}/setup-msys2/msys2.CMD"
 
       - name: Initialize Submodules
         # libx265 has issues when using the recursive method of the first checkout action

CMakeLists.txt

@@ -51,11 +51,17 @@ elseif(NOT N MATCHES "^[0-9]+$")
     set(N_PROC 1)
 endif()
 
+set(MSYS2_ROOT "C:/msys64")
+if(WIN32 AND DEFINED ENV{MSYS2_ROOT})
+    set(MSYS2_ROOT "$ENV{MSYS2_ROOT}")
+    message(STATUS "Detected MSYS2_ROOT, get msys2 path from environment: ${MSYS2_ROOT}")
+endif()
+
 if(NOT DEFINED BASH_EXECUTABLE)
     find_program(BASH_EXECUTABLE
             NAMES zsh bash
             REQUIRED
-            HINTS D:/a/_temp/msys64/usr/bin C:/msys64/usr/bin /bin /usr/bin /usr/local/bin)
+            HINTS "${MSYS2_ROOT}/usr/bin" /bin /usr/bin /usr/local/bin)
     message(STATUS "Found bash: ${BASH_EXECUTABLE}")
 endif()
 
@@ -70,12 +76,25 @@ if(WIN32)
     set(MAKE_EXECUTABLE "make")
     message(STATUS "Detected Windows, falling back to using make: ${MAKE_EXECUTABLE}")
 
+    # fatal error when cross compiling
+    if(CMAKE_CROSSCOMPILING)
+        message(STATUS "System processor: ${CMAKE_SYSTEM_PROCESSOR}")
+        message(STATUS "Host system processor: ${CMAKE_HOST_SYSTEM_PROCESSOR}")
+        message(FATAL_ERROR "Cross-compiling is not supported on Windows")
+    endif()
+
     set(MSYSTEM "UCRT64")
-    find_file(MSYS2_EXECUTABLE NAMES msys2_shell.cmd REQUIRED HINTS D:/a/_temp/msys64 C:/msys64)
+    set(MSYS2_ARG "-ucrt64")
+    if(CMAKE_SYSTEM_PROCESSOR MATCHES "ARM64")
+        set(MSYSTEM "CLANGARM64")
+        set(MSYS2_ARG "-clangarm64")
+    endif()
+
+    find_file(MSYS2_EXECUTABLE NAMES msys2_shell.cmd REQUIRED HINTS ${MSYS2_ROOT})
     message(STATUS "Found MSYS2: ${MSYS2_EXECUTABLE}")
 
     if(NOT DEFINED MSYS2_OPTION OR MSYS2_OPTION STREQUAL "1" OR MSYS2_OPTION STREQUAL "")
-        set(SHELL_CMD ${MSYS2_EXECUTABLE} -ucrt64 -defterm -here -no-start -shell bash -c)
+        set(SHELL_CMD ${MSYS2_EXECUTABLE} ${MSYS2_ARG} -defterm -here -no-start -shell bash -c)
     elseif(MSYS2_OPTION STREQUAL "2")
         # Theoretically, this is equivalent to the above
         configure_file(${CMAKE_CURRENT_SOURCE_DIR}/msys2.cmd.in ${CMAKE_CURRENT_BINARY_DIR}/msys2.cmd @ONLY)
@@ -135,7 +154,7 @@ message(STATUS "Initial PKG_CONFIG_PATH: ${PKG_CONFIG_PATH}")
 find_program(PKG_CONFIG_EXECUTABLE
         NAMES pkg-config
         REQUIRED
-        HINTS D:/a/_temp/msys64/usr/bin C:/msys64/usr/bin /bin /usr/bin /usr/local/bin)
+        HINTS "${MSYS2_ROOT}/usr/bin" /bin /usr/bin /usr/local/bin)
 UNIX_PATH(PKG_CONFIG_EXECUTABLE ${PKG_CONFIG_EXECUTABLE})
 message(STATUS "Found pkg-config: ${PKG_CONFIG_EXECUTABLE}")
 

README.md

@@ -121,7 +121,13 @@ brew install \
 
 #### Windows
 
-First, install [MSYS2](https://www.msys2.org/), then open the UCRT64 shell and run the following commands:
+ℹ️ Cross-compilation is not supported on Windows. You must build on the target architecture.
+
+First, install [MSYS2](https://www.msys2.org/).
+
+##### x86_64 / amd64
+
+Open the UCRT64 shell and run the following commands:
 
 ```bash
 pacman -Syu
@@ -139,6 +145,26 @@ pacman -S \
     mingw-w64-ucrt-x86_64-onevpl
 ```
 
+##### aarch64 / arm64
+
+Open the CLANGARM64 shell and run the following commands:
+
+```bash
+pacman -Syu
+pacman -S \
+    diffutils \
+    git \
+    make \
+    pkg-config \
+    mingw-w64-clang-aarch64-binutils \
+    mingw-w64-clang-aarch64-cmake \
+    mingw-w64-clang-aarch64-gcc \
+    mingw-w64-clang-aarch64-make \
+    mingw-w64-clang-aarch64-nasm \
+    mingw-w64-clang-aarch64-ninja \
+    mingw-w64-clang-aarch64-onevpl
+```
+
 ### Configure
 
 Use the `Unix Makefiles` generator for Linux and macOS, and the `MSYS Makefiles` generator for Windows.

cmake/ffmpeg/ffmpeg.cmake

@@ -52,17 +52,35 @@ list(APPEND FFMPEG_EXTRA_CONFIGURE
 if(WIN32)
     list(APPEND FFMPEG_EXTRA_CONFIGURE
             --enable-amf
-            --enable-cuda
             --enable-d3d11va
             --enable-encoder=h264_amf,hevc_amf,av1_amf
             --enable-encoder=h264_mf,hevc_mf
-            --enable-encoder=h264_nvenc,hevc_nvenc,av1_nvenc
             --enable-encoder=h264_qsv,hevc_qsv,av1_qsv
-            --enable-ffnvcodec
             --enable-libvpl
-            --enable-nvenc
             --enable-mediafoundation
     )
+
+    # On Windows Arm64
+    # We must specify the arch parameter until one of the following issues is resolved
+    #
+    # https://github.com/msys2/msys2-runtime/issues/171
+    # https://github.com/FFmpeg/FFmpeg/blob/4e5523c98597a417eb43555933b1075d18ec5f8b/configure#L4161
+    #
+    # We must disable CUDA and NVENC until following issues is resolved
+    #
+    # https://github.com/FFmpeg/FFmpeg/blob/4e5523c98597a417eb43555933b1075d18ec5f8b/configure#L7443
+    if(${arch} STREQUAL "aarch64" OR ${arch} STREQUAL "arm64")
+        list(APPEND FFMPEG_EXTRA_CONFIGURE
+                --arch=${arch}
+        )
+    elseif (${arch} STREQUAL "amd64" OR ${arch} STREQUAL "x86_64")
+        list(APPEND FFMPEG_EXTRA_CONFIGURE
+                --enable-cuda
+                --enable-encoder=h264_nvenc,hevc_nvenc,av1_nvenc
+                --enable-ffnvcodec
+                --enable-nvenc
+        )
+    endif()
 elseif(APPLE)
     list(APPEND FFMPEG_EXTRA_CONFIGURE
             --enable-encoder=h264_videotoolbox,hevc_videotoolbox

cmake/ffmpeg/x264.cmake

@@ -19,9 +19,9 @@ else()
 endif()
 
 if(WIN32)
-    set(X264_HOST ${X264_ARCH}-windows)
+    set(X264_HOST ${X264_ARCH}-mingw64)
 elseif(APPLE)
-    set(X264_HOST ${X264_ARCH}-macos)
+    set(X264_HOST ${X264_ARCH}-darwin)
 elseif(UNIX)
     set(X264_HOST ${X264_ARCH}-linux)
 else()
@@ -37,6 +37,17 @@ if(CMAKE_CROSSCOMPILING)
     endif()
 endif()
 
+# On Windows Arm64
+# We must specify the host parameter until one of the following issues is resolved
+#
+# https://github.com/msys2/msys2-runtime/issues/171
+# https://code.videolan.org/videolan/x264/-/tree/1ecc51ee971e0056a53bd6cf9c6f6af18b167e4b/config.guess#L809
+if(${X264_HOST} STREQUAL "aarch64-mingw64")
+    set(FFMPEG_X264_EXTRA_CONFIGURE
+            --host=${X264_HOST}
+    )
+endif()
+
 # convert list to string
 # configure command will only take the first argument if not converted to string
 string(REPLACE ";" " " FFMPEG_X264_EXTRA_CONFIGURE "${FFMPEG_X264_EXTRA_CONFIGURE}")

msys2.cmd.in

@@ -3,4 +3,4 @@ setlocal
 IF NOT DEFINED MSYSTEM set MSYSTEM=@MSYSTEM@
 IF NOT DEFINED MSYS2_PATH_TYPE set MSYS2_PATH_TYPE=inherit
 set CHERE_INVOKING=1
-@MSYS2_EXECUTABLE@ -ucrt64 -defterm -here -no-start -shell bash -c %*
+@MSYS2_EXECUTABLE@ @MSYS2_ARG@ -defterm -here -no-start -shell bash -c %*