Use pre-built binaries for ffmpeg extension (#3460)

Summary:
This commit changes the way FFmpeg extension is built.

Originally, the build process expected the FFmpeg binaries to be somehow available in build env.
This makes the build process unpredictable and prevents default enabling FFmpeg extension.

The proposed change uses pre-built FFmpeg binaries as build-time only scaffold, which are built in our CI job https://github.com/pytorch/audio/actions/workflows/ffmpeg.yml.

This makes the build process more predictable and removes the necessity to build FFmpeg in our CI.
Currently, it supports macOS (arm64, x86_64), unix (x86_64, aarch64) and windows (amd64).
The downside is that it no longer works with the architecture not listed above.
We can potentially workaround by searching the FFmpeg binaries available in system (the old way) for
these system, but since they are not supported by PyTorch, the priority is low.

Pull Request resolved: #3460

Differential Revision: D47261885

Pulled By: mthrok

fbshipit-source-id: 223a15e95c9140c95688af968beb35ff40354476

Author: mthrok

CMakeLists.txt

@@ -171,6 +171,7 @@ if (BUILD_SOX)
   add_subdirectory(torchaudio/csrc/sox)
 endif()
 if (USE_FFMPEG)
+  add_subdirectory(third_party/ffmpeg)
   add_subdirectory(torchaudio/csrc/ffmpeg)
 endif()
 if (BUILD_CUDA_CTC_DECODER)

cmake/FindFFMPEG.cmake

@@ -0,0 +1,91 @@
+################################################################################
+# This file defines the following FFmpeg libraries using pre-built binaries.
+
+add_library(ffmpeg4 INTERFACE)
+add_library(ffmpeg ALIAS ffmpeg4)
+
+################################################################################
+
+include(FetchContent)
+
+set(base_url https://pytorch.s3.amazonaws.com/torchaudio/ffmpeg)
+
+if (APPLE)
+  if ("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "arm64")
+    FetchContent_Declare(
+      f4
+      URL ${base_url}/2023-07-06/macos_arm64/4.1.8.tar.gz
+      URL_HASH SHA256=a44b8152b7f204ce5050fc7f6fd2bbbafe7ae4e45f03e135f3b45dd9a08f404e
+      )
+  elseif ("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "x86_64")
+    FetchContent_Declare(
+      f4
+      URL ${base_url}/2023-07-06/macos_x86_64/4.1.8.tar.gz
+      URL_HASH SHA256=392d5af0b24535bfc69d6244e7595e5f07117b93d94505d0a4b34c82ae479f48
+      )
+  else ()
+    message(
+      FATAL_ERROR
+      "CPU architecture ${CMAKE_SYSTEM_PROCESSOR} is not currently supported. If you do not need FFmpeg integration, then setting USE_FFMPEG=0 will bypass the issue.")
+  endif()
+elseif (UNIX)
+  if ("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "aarch64")
+    FetchContent_Declare(
+      f4
+      URL ${base_url}/2023-07-06/linux_aarch64/4.1.8.tar.gz
+      URL_HASH SHA256=aae0b713040e30ceebe0d0bc82353d3d9054055c7af8a4f4abc1766015ab7681
+    )
+  elseif ("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "x86_64")
+    FetchContent_Declare(
+      f4
+      URL ${base_url}/2023-07-06/linux_x86_64/4.1.8.tar.gz
+      URL_HASH SHA256=52e53b8857739bdd54f9d8541e22569b57f6c6f16504ee83963c2ed3e7061a23
+      )
+  else ()
+    # Possible case ppc64le (though it's not officially supported.)
+    message(
+      FATAL_ERROR
+      "CPU architecture ${CMAKE_SYSTEM_PROCESSOR} is not currently supported. If you do not need FFmpeg integration, then setting USE_FFMPEG=0 will bypass the issue.")
+  endif()
+elseif(MSVC)
+  FetchContent_Declare(
+    f4
+    URL ${base_url}/2023-07-06/windows/4.1.8.tar.gz
+    URL_HASH SHA256=c45cd36e0575490f97ace07365bb67c5e1cbe9f3e6a4272d035c19348df96790
+    )
+endif()
+
+FetchContent_MakeAvailable(f4)
+target_include_directories(ffmpeg4 INTERFACE ${f4_SOURCE_DIR}/include)
+
+if(APPLE)
+  target_link_libraries(
+    ffmpeg4
+    INTERFACE
+    ${f4_SOURCE_DIR}/lib/libavutil.56.dylib
+    ${f4_SOURCE_DIR}/lib/libavcodec.58.dylib
+    ${f4_SOURCE_DIR}/lib/libavformat.58.dylib
+    ${f4_SOURCE_DIR}/lib/libavdevice.58.dylib
+    ${f4_SOURCE_DIR}/lib/libavfilter.7.dylib
+    )
+elseif (UNIX)
+  target_link_libraries(
+    ffmpeg4
+    INTERFACE
+    ${f4_SOURCE_DIR}/lib/libavutil.so.56
+    ${f4_SOURCE_DIR}/lib/libavcodec.so.58
+    ${f4_SOURCE_DIR}/lib/libavformat.so.58
+    ${f4_SOURCE_DIR}/lib/libavdevice.so.58
+    ${f4_SOURCE_DIR}/lib/libavfilter.so.7
+    )
+elseif(MSVC)
+  target_link_libraries(
+    ffmpeg4
+    INTERFACE
+    ${f4_SOURCE_DIR}/bin/avutil.lib
+    ${f4_SOURCE_DIR}/bin/avcodec.lib
+    ${f4_SOURCE_DIR}/bin/avformat.lib
+    ${f4_SOURCE_DIR}/bin/avdevice.lib
+    ${f4_SOURCE_DIR}/bin/avfilter.lib
+    )
+endif()

third_party/ffmpeg/CMakeLists.txt

@@ -36,7 +36,7 @@ def _get_build(var, default=False):
 _BUILD_SOX = False if platform.system() == "Windows" else _get_build("BUILD_SOX", True)
 _BUILD_RIR = _get_build("BUILD_RIR", True)
 _BUILD_RNNT = _get_build("BUILD_RNNT", True)
-_USE_FFMPEG = _get_build("USE_FFMPEG", False)
+_USE_FFMPEG = _get_build("USE_FFMPEG", True)
 _USE_ROCM = _get_build("USE_ROCM", torch.backends.cuda.is_built() and torch.version.hip is not None)
 _USE_CUDA = _get_build("USE_CUDA", torch.backends.cuda.is_built() and torch.version.hip is None)
 _BUILD_ALIGN = _get_build("BUILD_ALIGN", True)

tools/setup_helpers/extension.py

@@ -1,10 +1,3 @@
-message(STATUS "FFMPEG_ROOT=$ENV{FFMPEG_ROOT}")
-find_package(FFMPEG 4.1 REQUIRED COMPONENTS avdevice avfilter avformat avcodec avutil)
-add_library(ffmpeg INTERFACE)
-target_include_directories(ffmpeg INTERFACE "${FFMPEG_INCLUDE_DIRS}")
-target_link_libraries(ffmpeg INTERFACE "${FFMPEG_LIBRARIES}")
-
-
 set(
   sources
   ffmpeg.cpp