Expose TorchCodecConfig.cmake (#938)

Co-authored-by: Dmitry Rogozhkin <dmitry.v.rogozhkin@gmail.com>
Co-authored-by: Nicolas Hug <nicolashug@meta.com>

Author: 3 people

CMakeLists.txt

@@ -1,6 +1,13 @@
 cmake_minimum_required(VERSION 3.18)
 project(TorchCodec)
 
+# Define LINUX platform variable globally
+if (UNIX AND NOT APPLE)
+    set(LINUX TRUE)
+else()
+    set(LINUX FALSE)
+endif()
+
 add_subdirectory(src/torchcodec/_core)
 
 

src/torchcodec/__init__.py

@@ -4,6 +4,8 @@
 # This source code is licensed under the BSD-style license found in the
 # LICENSE file in the root directory of this source tree.
 
+from pathlib import Path
+
 # Note: usort wants to put Frame and FrameBatch after decoders and samplers,
 # but that results in circular import.
 from ._frame import AudioSamples, Frame, FrameBatch  # usort:skip # noqa
@@ -14,3 +16,12 @@
     from .version import __version__  # noqa: F401
 except Exception:
     pass
+
+# cmake_prefix_path is needed for downstream cmake-based builds that use
+# torchcodec as a dependency to tell cmake where torchcodec is installed and where to find its
+# CMake configuration files.
+# Pytorch itself has a similar mechanism which we use in our setup.py!
+cmake_prefix_path = Path(__file__).parent / "share" / "cmake"
+# Similarly, these are exposed for downstream builds that use torchcodec as a
+# dependency.
+from ._core import core_library_path, ffmpeg_major_version  # usort:skip

src/torchcodec/_core/CMakeLists.txt

@@ -245,16 +245,16 @@ if(DEFINED ENV{BUILD_AGAINST_ALL_FFMPEG_FROM_S3})
         you still need a different FFmpeg to be installed for run time!"
     )
 
-    # This will expose the ffmpeg4, ffmpeg5, ffmpeg6, ffmpeg7, and ffmpeg8 targets
+    # This will expose the torchcodec::ffmpeg{N} (N=4,5,6,7,8) targets
     include(
         ${CMAKE_CURRENT_SOURCE_DIR}/fetch_and_expose_non_gpl_ffmpeg_libs.cmake
     )
 
-    make_torchcodec_libraries(8 ffmpeg8)
-    make_torchcodec_libraries(7 ffmpeg7)
-    make_torchcodec_libraries(6 ffmpeg6)
-    make_torchcodec_libraries(4 ffmpeg4)
-    make_torchcodec_libraries(5 ffmpeg5)
+    make_torchcodec_libraries(8 torchcodec::ffmpeg8)
+    make_torchcodec_libraries(7 torchcodec::ffmpeg7)
+    make_torchcodec_libraries(6 torchcodec::ffmpeg6)
+    make_torchcodec_libraries(4 torchcodec::ffmpeg4)
+    make_torchcodec_libraries(5 torchcodec::ffmpeg5)
 else()
     message(
         STATUS
@@ -263,40 +263,12 @@ else()
         installed FFmpeg from conda, make sure pkg-config is installed from
         conda as well."
     )
-    find_package(PkgConfig REQUIRED)
-    pkg_check_modules(LIBAV REQUIRED IMPORTED_TARGET
-        libavdevice
-        libavfilter
-        libavformat
-        libavcodec
-        libavutil
-        libswresample
-        libswscale
-    )
 
-    # Split libavcodec's version string by '.' and convert it to a list
-    string(REPLACE "." ";" libavcodec_version_list ${LIBAV_libavcodec_VERSION})
-    # Get the first element of the list, which is the major version
-    list(GET libavcodec_version_list 0 libavcodec_major_version)
-
-    if (${libavcodec_major_version} STREQUAL "58")
-        set(ffmpeg_major_version "4")
-    elseif (${libavcodec_major_version} STREQUAL "59")
-        set(ffmpeg_major_version "5")
-    elseif (${libavcodec_major_version} STREQUAL "60")
-        set(ffmpeg_major_version "6")
-    elseif (${libavcodec_major_version} STREQUAL "61")
-        set(ffmpeg_major_version "7")
-    elseif (${libavcodec_major_version} STREQUAL "62")
-        set(ffmpeg_major_version "8")
-    else()
-        message(
-            FATAL_ERROR
-            "Unsupported libavcodec version: ${libavcodec_major_version}"
-        )
-    endif()
+    # This will expose `add_ffmpeg_target_with_pkg_config`
+    include("${CMAKE_CURRENT_SOURCE_DIR}/../share/cmake/TorchCodec/ffmpeg_versions.cmake")
 
-    make_torchcodec_libraries(${ffmpeg_major_version} PkgConfig::LIBAV)
+    add_ffmpeg_target_with_pkg_config(ffmpeg_major_version)
+    make_torchcodec_libraries(${ffmpeg_major_version} torchcodec::ffmpeg${ffmpeg_major_version})
 
     # Expose these values updwards so that the test compilation does not need
     # to re-figure it out. FIXME: it's not great that we just copy-paste the

src/torchcodec/_core/__init__.py

@@ -19,6 +19,7 @@
     _test_frame_pts_equality,
     add_audio_stream,
     add_video_stream,
+    core_library_path,
     create_from_bytes,
     create_from_file,
     create_from_file_like,
@@ -29,6 +30,7 @@
     encode_video_to_file,
     encode_video_to_file_like,
     encode_video_to_tensor,
+    ffmpeg_major_version,
     get_ffmpeg_library_versions,
     get_frame_at_index,
     get_frame_at_pts,

src/torchcodec/_core/fetch_and_expose_non_gpl_ffmpeg_libs.cmake

@@ -9,20 +9,12 @@ 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 (LINUX)
-    set(lib_dir "lib")
-
     set(
         platform_url
         ${base_url}/linux_x86_64
@@ -48,58 +40,7 @@ if (LINUX)
         f8_sha256
         c55b3c1a4b5e4d5fdd7c632bea3ab6f45b4e37cc8e0999dda3f84a8ed8defad8
     )
-    set(
-       f4_library_file_names
-       libavutil.so.56
-       libavcodec.so.58
-       libavformat.so.58
-       libavdevice.so.58
-       libavfilter.so.7
-       libswscale.so.5
-       libswresample.so.3
-    )
-    set(
-       f5_library_file_names
-       libavutil.so.57
-       libavcodec.so.59
-       libavformat.so.59
-       libavdevice.so.59
-       libavfilter.so.8
-       libswscale.so.6
-       libswresample.so.4
-    )
-    set(
-       f6_library_file_names
-       libavutil.so.58
-       libavcodec.so.60
-       libavformat.so.60
-       libavdevice.so.60
-       libavfilter.so.9
-       libswscale.so.7
-       libswresample.so.4
-    )
-    set(
-       f7_library_file_names
-       libavutil.so.59
-       libavcodec.so.61
-       libavformat.so.61
-       libavdevice.so.61
-       libavfilter.so.10
-       libswscale.so.8
-       libswresample.so.5
-    )
-    set(
-       f8_library_file_names
-       libavutil.so.60
-       libavcodec.so.62
-       libavformat.so.62
-       libavdevice.so.62
-       libavfilter.so.11
-       libswscale.so.9
-       libswresample.so.6
-    )
 elseif (APPLE)
-    set(lib_dir "lib")
     set(
         platform_url
         ${base_url}/macos_arm64
@@ -124,60 +65,7 @@ elseif (APPLE)
         f8_sha256
         beb936b76f25d2621228a12cdb67c9ae3d1eff7aa713ef8d1167ebf0c25bd5ec
     )
-
-    set(
-       f4_library_file_names
-       libavutil.56.dylib
-       libavcodec.58.dylib
-       libavformat.58.dylib
-       libavdevice.58.dylib
-       libavfilter.7.dylib
-       libswscale.5.dylib
-       libswresample.3.dylib
-    )
-    set(
-       f5_library_file_names
-       libavutil.57.dylib
-       libavcodec.59.dylib
-       libavformat.59.dylib
-       libavdevice.59.dylib
-       libavfilter.8.dylib
-       libswscale.6.dylib
-       libswresample.4.dylib
-    )
-    set(
-       f6_library_file_names
-       libavutil.58.dylib
-       libavcodec.60.dylib
-       libavformat.60.dylib
-       libavdevice.60.dylib
-       libavfilter.9.dylib
-       libswscale.7.dylib
-       libswresample.4.dylib
-    )
-    set(
-       f7_library_file_names
-       libavutil.59.dylib
-       libavcodec.61.dylib
-       libavformat.61.dylib
-       libavdevice.61.dylib
-       libavfilter.10.dylib
-       libswscale.8.dylib
-       libswresample.5.dylib
-    )
-    set(
-       f8_library_file_names
-       libavutil.60.dylib
-       libavcodec.62.dylib
-       libavformat.62.dylib
-       libavdevice.62.dylib
-       libavfilter.11.dylib
-       libswscale.9.dylib
-       libswresample.6.dylib
-    )
-
 elseif (WIN32)
-    set(lib_dir "bin")
     set(
         platform_url
         ${base_url}/windows_x86_64
@@ -202,57 +90,6 @@ elseif (WIN32)
         f8_sha256
         bac845ac79876b104959cb0e7b9dec772a261116344dd17d2f97e7ddfac4a73f
     )
-
-    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
-    )
-    set(
-        f8_library_file_names
-        avutil.lib
-        avcodec.lib
-        avformat.lib
-        avdevice.lib
-        avfilter.lib
-        swscale.lib
-        swresample.lib
-    )
 else()
     message(
         FATAL_ERROR
@@ -293,68 +130,12 @@ FetchContent_Declare(
 
 FetchContent_MakeAvailable(f4 f5 f6 f7 f8)
 
-add_library(ffmpeg4 INTERFACE)
-add_library(ffmpeg5 INTERFACE)
-add_library(ffmpeg6 INTERFACE)
-add_library(ffmpeg7 INTERFACE)
-add_library(ffmpeg8 INTERFACE)
+# makes add_ffmpeg_target available
+include("${CMAKE_CURRENT_SOURCE_DIR}/../share/cmake/TorchCodec/ffmpeg_versions.cmake")
 
 # Note: the f?_SOURCE_DIR variables were set by FetchContent_MakeAvailable
-target_include_directories(ffmpeg4 INTERFACE ${f4_SOURCE_DIR}/include)
-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)
-target_include_directories(ffmpeg8 INTERFACE ${f8_SOURCE_DIR}/include)
-
-
-list(
-    TRANSFORM f4_library_file_names
-    PREPEND ${f4_SOURCE_DIR}/${lib_dir}/
-    OUTPUT_VARIABLE f4_library_paths
-)
-list(
-    TRANSFORM f5_library_file_names
-    PREPEND ${f5_SOURCE_DIR}/${lib_dir}/
-    OUTPUT_VARIABLE f5_library_paths
-)
-list(
-    TRANSFORM f6_library_file_names
-    PREPEND ${f6_SOURCE_DIR}/${lib_dir}/
-    OUTPUT_VARIABLE f6_library_paths
-)
-list(
-    TRANSFORM f7_library_file_names
-    PREPEND ${f7_SOURCE_DIR}/${lib_dir}/
-    OUTPUT_VARIABLE f7_library_paths
-)
-list(
-    TRANSFORM f8_library_file_names
-    PREPEND ${f8_SOURCE_DIR}/${lib_dir}/
-    OUTPUT_VARIABLE f8_library_paths
-)
-
-target_link_libraries(
-    ffmpeg4
-    INTERFACE
-    ${f4_library_paths}
-)
-target_link_libraries(
-    ffmpeg5
-    INTERFACE
-    ${f5_library_paths}
-)
-target_link_libraries(
-    ffmpeg6
-    INTERFACE
-    ${f6_library_paths}
-)
-target_link_libraries(
-    ffmpeg7
-    INTERFACE
-    ${f7_library_paths}
-)
-target_link_libraries(
-    ffmpeg8
-    INTERFACE
-    ${f8_library_paths}
-)
+add_ffmpeg_target(4 "${f4_SOURCE_DIR}")
+add_ffmpeg_target(5 "${f5_SOURCE_DIR}")
+add_ffmpeg_target(6 "${f6_SOURCE_DIR}")
+add_ffmpeg_target(7 "${f7_SOURCE_DIR}")
+add_ffmpeg_target(8 "${f8_SOURCE_DIR}")