WebRTC Cross-Platform Build Guide

1. WebRTC Versions

WebRTC versions and corresponding branch-heads are listed on Chromiumdash. The latest was M128 at the time of writing.

20240731115047

2. Downloading the Code

Create a webrtc directory. Google repositories are not reachable from mainland China without a proxy.

2.1. Proxy Configuration

Create an http_proxy.boto proxy config file in the webrtc directory:

[Boto] 
proxy=127.0.0.1
proxy_port=7890  # 端口根据自己配置的代理工具来

Declare the proxy

export NO_AUTH_BOTO_CONFIG=~/webrtc/proxy.boto

Configure git proxy

Edit ~/.gitconfig and add:

[http]
	proxy = 127.0.0.1:7890
[https]
	proxy = 127.0.0.1:7890

Configure terminal proxy

Mainly for curl, wget, and Python scripts:

export https_proxy=http://127.0.0.1:7890 http_proxy=http://127.0.0.1:7890 all_proxy=socks5://127.0.0.1:7890

2.2. depot_tools

Clone the repository and add depot_tools to your PATH. Commands like gn, gclient, and ninja live there.

git clone https://chromium.googlesource.com/chromium/tools/depot_tools

Edit ~/.zshrc or ~/.bashrc and add the following. Adjust the path to your install location.

# depot_tools
export PATH="/Users/admin/repos/tools/depot_tools:$PATH"

Verify configuration:

source ~/.zshrc
which gclient

Reference

https://www.chromium.org/developers/how-tos/install-depot-tools/

2.3. iOS and MacOS

fetch --nohooks webrtc_ios
gclient sync --with_branch_heads

2.4. Android

Run the following in the webrtc directory:

fetch --nohooks webrtc_android
gclient sync --with_branch_heads

2.5. Windows

fetch --nohooks webrtc
gclient sync --with_branch_heads

2.6. All Platforms

To fetch code for all platforms at once, create a .gclient file with the following. target_os lists every platform to fetch.

solutions = [
  {
    "name": "src",
    "url": "https://webrtc.googlesource.com/src.git",
    "deps_file": "DEPS",
    "managed": False,
    "custom_deps": {},
  },
]
target_os = ["ios", "mac", "android", "win", "unix"]

Then run:

gclient sync --with_branch_heads

The .gclient_entries file is auto-generated next to src and lists all WebRTC dependency repositories.

If download fails, check proxy settings and run gclient sync again until it reaches 100%. {: .prompt-info }

About gclient

It syncs all repositories in a solution. Common flags:

-f, --force: force update unchanged modules;
--with_branch_heads: clone branch_heads refspecs in addition to default refspecs;
--with_tags: clone git tags in addition to default refspecs;
--no-history: do not fetch git commit history;
--revision <version>: check out a specific version;
--nohooks: do not run hooks after sync.

3. Switching Branches

After gclient sync --with_branch_head, you will see branch heads like below.

20240731135153 fetched branch_heads

Switch branch

# webrtc src 目录
cd src
# 创建m128对应的 branch-heads/6633 分支
git checkout -b M128/6613 branch-heads/6613

# 同步该节点依赖的三方库，必须要执行
gclient sync --nohooks

4. Building

4.1. iOS

Generate project

# debug build for 64-bit iOS
gn gen out/ios_64 --args='target_os="ios" target_cpu="arm64" ios_enable_code_signing=false'

# debug build for simulator
gn gen out/ios_sim --args='target_os="ios" target_cpu="x64" ios_enable_code_signing=false'

Build

ninja -C out/ios_64 AppRTCMobile

Build with Xcode

# 生成xcode工程
gn gen out/ios --args='target_os="ios" target_cpu="arm64" ios_enable_code_signing=false' --ide=xcode
# 打开xcode工程
open -a Xcode.app out/ios/all.xcworkspace

ios_enable_code_signing=false avoids code signing errors when generating the project. See end of article for more gn options. {: .prompt-info }

4.2. MacOS

Generate project

Apple Silicon:

gn gen  out/mac_debug --args='target_os="mac" target_cpu="arm64"' --ide=xcode

Intel Mac:


# xcode 
gn gen out/mac_debug --args='target_os="mac" target_cpu="x64"' --ide=xcode

Build

ninja -C out/mac_debug AppRTCMobile
# 或
open -a Xcode.app out/mac_debug/all.xcworkspace

4.3. Android

Install dependencies

On Ubuntu or Debian, install build dependencies by running the script under webrtc/src/build:

./build/install-build-deps.sh

Generate project

# arm
gn gen out/Debug --args='target_os="android" target_cpu="arm"'

# arm64
gn gen out/Debug --args='target_os="android" target_cpu="arm64"'

# x86
gn gen out/Debug --args='target_os="android" target_cpu="x86"'

# x64
gn gen out/Debug --args='target_os="android" target_cpu="x64"'

Debug is the default. For release, add is_debug=false. See end of article for more options. {: .prompt-info }

Generate Android Studio project (optional)

# Import the project in Android Studio. (Do not just open it.) The project is located in out/Debug/gradle.
build/android/gradle/generate_gradle.py --output-directory $PWD/out/Debug \
--target "//examples:AppRTCMobile" --use-gradle-process-resources \
--split-projects

Build

ninja -C out/Debug

Android code can be downloaded on macOS, but official builds are supported only on Ubuntu. For building on macOS, see here. {: .prompt-info }

4.4. Windows

Generate project

gn gen out/Debug --args="target_os=\"win\" target_cpu=\"x64\" is_component_build=false rtc_enable_protobuf=true rtc_use_h264=true rtc_initialize_ffmpeg=true ffmpeg_branding=\"Chrome\" rtc_include_tests=false " --ide=vs2015

Build

ninja -C out/Debug
# 或使用vs打开工程编译

Reference: Widows编译WebRTC

5. Build Arguments

List all build arguments for a generated output directory, e.g. out/ios:

gn args out/ios --list

Common gn arguments to reduce build time and binary size:

# 开启rtti, 默认开启
use_rtti=true 
# 开启debug, 默认开启  
is_debug=true 
# 开启h264编码
is_component_build=false 
rtc_use_h264=true 
# 开启protobuf
rtc_enable_protobuf=true 
 # 是否编译测试代码，默认true
rtc_include_tests=false  
 # 是否编译示例代码，默认true
rtc_build_examples=false

proprietary_codecs=true

rtc_enable_sctp=false 
# 禁用libevent
rtc_enable_libevent=false 
# 指定ffmepg 版本
ffmpeg_branding="Chrome"
# 
rtc_build_tools=false 
# 禁用android lint
disable_android_lint=false
 #禁用 webrtc自带的libc++库，防止和标准库冲突，如果编译动态库可以打开
use_custom_libcxx=false
#使用非 webrtc自带的libc++库，防止和标准库冲突
use_custom_libcxx_for_host=true 
 # 仅针对安卓
android32_ndk_api_level=18 
 # 仅针对iOS和Mac，启用签名
ios_enable_code_signing=false 
 # 编译警告当错误处理
treat_warnings_as_errors=true 
# 开启libaom，AV1编码
enable_libaom=true 
 # 开启libvpx，VP9编码
rtc_libvpx_build_vp9=false
# 生成DSYM文件, 防止Mac和iOS断点不停止问题
enable_dsyms=true