overte/cmake/ports/webrtc

WebRTC

WebRTC Information:

• https://webrtc.org/
• https://webrtc.googlesource.com/src
• https://webrtc.googlesource.com/src/+/refs/heads/master/docs/native-code/index.md
  • https://webrtc.googlesource.com/src/+/refs/heads/master/docs/native-code/development/prerequisite-sw/index.md
  • https://webrtc.googlesource.com/src/+/refs/heads/master/docs/native-code/development/index.md
• https://www.chromium.org/developers/calendar
• https://github.com/microsoft/winrtc
• https://docs.microsoft.com/en-us/winrtc/getting-started
• https://groups.google.com/g/discuss-webrtc
  See "PSA" posts for release information.
• https://bugs.chromium.org/p/webrtc/issues/list
• https://stackoverflow.com/questions/27809193/webrtc-not-building-for-windows
• https://github.com/aisouard/libwebrtc/issues/57

Windows - M84

WebRTC's M84 release is currently used because it corresponded to Microsoft's latest WinRTC release at the time of development, and WinRTC is a source of potentially useful patches.

The following notes document how the M84-based Windows VCPKG was created, using Visual Studio 2019.

Set Up depot_tools

Install Google's depot_tools.

• Download depot_tools.zip.
• Extract somewhere.
• Add the extracted directory to the start of the system PATH environment variable.

Configure depot_tools.

• Set an environment variable DEPOT_TOOLS_WIN_TOOLCHAIN=0
• Set an environment variable GYP_MSVS_VERSION=2019

Initialize depot_tools.

• VS2019 developer command prompt in the directory where the source tree will be created.
• gclient

Get the Code

Fetch the code into a \src subdirectory. This may take some time!

• fetch --nohooks webrtc

Switch to the M84 branch.

• cd src
• git checkout branch-heads/4147

Fetch all the subrepositories.

• gclient sync -D -r branch-heads/4147

Patch the Code

Modify compiler switches

• Edit build\config\win\BUILD.gn:
  • Change all /MT to /MD, and /MTd to /MDd.
  • Change all cflags = [ "/MDd" ] to [ "/MDd", "-D_ITERATOR_DEBUG_LEVEL=2", "-D_HAS_ITERATOR_DEBUGGING=1" ].
• Edit build\config\compiler\BUILD.gn:
  Change:

    if (is_win) {
      if (is_clang) {
        cflags = [ "/Z7" ]  # Debug information in the .obj files.
      } else {
        cflags = [ "/Zi" ]  # Produce PDB file, no edit and continue.
      }
  

  to:

    if (is_win) {
      if (is_clang) {
        cflags = [ "/Z7", "/std:c++17", "/Zc:__cplusplus" ]  # Debug information in the .obj files.
      } else {
        cflags = [ "/Zi", "/std:c++17", "/Zc:__cplusplus" ]  # Produce PDB file, no edit and continue.
      }
  

H265 Codec Fixes

https://bugs.webrtc.org/9213#c13

• Edit the following files:
  • modules\video_coding\codecs\h264\h264_color_space.h
  • modules\video_coding\codecs\h264\h264_decoder_impl.h
  • modules\video_coding\codecs\h264\h264_encoder_impl.h In each, comment out the following lines:

  #if defined(WEBRTC_WIN) && !defined(__clang__)
  #error "See: bugs.webrtc.org/9213#c13."
  #endif
  

• Edit third_party\ffmpeg\libavcodec\fft_template.c:
  Comment out all of ff_fft_init except the fail clause at the end.
• Edit third_party\ffmpeg\libavcodec\pcm.c:
  Comment out last line, containing PCM Archimedes VIDC.
• Edit third_party\ffmpeg\libavutil\x86\imgutils_init.c:
  Add the following method to the end of the file:

  void avpriv_emms_asm(void) {}  // Fix missing symbol in FFMPEG.
  

Exclude BoringSSL

A separate OpenSSL VCPKG is used for building Overte. The following patches are needed even though SSL is excluded in the gn gen build commands.

• Rename third_party\boringssl to third_party\boringssl-NO.

• Edit *third_party\libsrtp\BUILD.gn:
  Change:

  public_deps = [
    "//third_party/boringssl:boringssl",
  ]
  

  To:

  public_deps = [
    # "//third_party/boringssl:boringssl",
  ]
  

• Edit third_party\usrsctp\BUILD.gn:
  Change:

  deps = [ "//third_party/boringssl" ]
  

  To:

  deps = [
    # "//third_party/boringssl"
  ]
  

• Edit base\BUILD.gn:
  In the code under:

  # Use the base implementation of hash functions when building for
  # NaCl. Otherwise, use boringssl.
  

  Change:

  if (is_nacl) {
  

  To:

  # if (is_nacl) {
  if (true) {
  

• Edit rtc_base\BUILD.gn:
  Change:

  if (rtc_build_ssl) {
    deps += [ "//third_party/boringssl" ]
  } else {
  

  To:

  if (rtc_build_ssl) {
    # deps += [ "//third_party/boringssl" ]
  } else {
  

Set Up OpenSSL

Do one of the following to provide OpenSSL for building against: a. If you have built Overte, find the HIFI_VCPKG_BASE subdirectory used in your build and make note of the path to and including the installed\x64-windows\include directory (which includes an openssl directory). a. Follow https://github.com/overte-org/vcpkg to install vcpkg and then openssl. Make note of the path to and including the packages\openssl-windows_x64-windows\include directory (which includes an openssl directory).

Copy the <path>\openssl directory to the following locations (i.e., add as openssl subdirectories):

• third_party\libsrtp\crypto\include
• third_party\usrsctp\usrsctplib\usrsctplib

Also use the path in the gn gen commands, below, making sure to escape \s as \\s.

Build and Package

Use a VS2019 developer command prompt in the src directory.

If it complains about the debugger being missing from your Windows SDK, modify your Windows "Software Development Kit" in your installed programs (See: https://stackoverflow.com/questions/46237620/how-to-install-debugging-tools-with-visual-studio-2017-installer).

Create a release build of the WebRTC library:

• gn gen --ide=vs2019 out\Release --filters=//:webrtc "--args=is_debug=false is_clang=false use_custom_libcxx=false libcxx_is_shared=true symbol_level=2 use_lld=false rtc_include_tests=false rtc_build_tools=false rtc_build_examples=false proprietary_codecs=true rtc_use_h264=true enable_libaom=false rtc_enable_protobuf=false rtc_build_ssl=false rtc_ssl_root=\"<path>\""
• ninja -C out\Release

Create a debug build of the WebRTC library:

• gn gen --ide=vs2019 out\Debug --filters=//:webrtc "--args=is_debug=true is_clang=false use_custom_libcxx=false libcxx_is_shared=true enable_iterator_debugging=true use_lld=false rtc_include_tests=false rtc_build_tools=false rtc_build_examples=false proprietary_codecs=true rtc_use_h264=true enable_libaom=false rtc_enable_protobuf=false rtc_build_ssl=false rtc_ssl_root=\"<path>\""
• ninja -C out\Debug

Create VCPKG file:

• Assemble files in VCPKG directory structure: Use the copy-VCPKG-files-win.cmd batch file per instructions in it.
  cd ..
copy-VCPKG-files-win
• Zip up the VCPKG webrtc directory created by the batch file.
  cd vcpkg
7z a -tzip webrtc-m84-yyyymmdd-windows.zip webrtc
• Calculate the SHA512 of the zip file. E.g., using a Windows PowerShell command window:
  Get-FileHash <filename> -Algorithm SHA512 | Format-List
• Convert the SHA512 to lower case. E.g., using Microsoft Word, select the SHA512 text and use Shift-F3 to change the case.
• Host the zip file on the Web.
• Update CONTROL and portfile.cmake with version number (revision date), zip file Web URL, and SHA512.

Tidying up

Disable the depot_tools:

• Rename the depot_tools directory so that these tools don't interfere with the rest of your development environment for other work.

Linux - M81

The original, High Fidelity-provided WebRTC VCPKG library is used for AEC (audio echo cancellation) only.

TODO: Update to M84 and include WebRTC components per Windows WebRTC.

MacOS - M78

The original, High Fidelity-provided WebRTC VCPKG library is used for AEC (audio echo cancellation) only.

TODO: Update to M84 and include WebRTC components per Windows WebRTC.