webrtc-delay-estimation

Delay estimation logic extracted from WebRTC.

How to build

This repository uses CMake to automate cross-platform builds. If it fails to build, please create an issue with the following informations:

• CMake version
• Platform (operating system with CPU architecture)
• Compiler name and version
• Error message produced by CMake

On Windows

1. Install Visual Studio and CMake. For Visual Studio 2017 and newer, instead of installing CMake by yourself, you can install a Visual Studio component called Visual C++ Tools for CMake, which greatly simplifies the process. If you are using an older version of Visual Studio, install standalone CMake.

2. Clone this repository with submodules.

git clone --recurse-submodules https://github.com/RangHo/webrtc-delay-estimation

VS2017 or newer

3. You can open the project by clicking File > Open > Folder in Visual Studio, and selecting the webrtc-delay-estimation folder you just cloned. Visual Studio should recognize CMakeLists.txt automatically. You can build the project as if it is a regular Visual Studio project.

VS2015 or older

3. For older versions of Visual Studio, you need to use CMake command line to generate project files. Generate .vcxproj files using the following command. Replace <generator> with the name of Visual Studio generator matching the version of Visual Studio you are using.

mkdir build
cd build
cmake -G "<generator>" ..

4. Open the .sln file CMake created, and build the solution.

On macOS and Linux (and any other POSIX systems)

1. Install CMake. For most distributions, there should be a package for your default package manager.

# Ubuntu
sudo apt-get install cmake

# Arch Linux
sudo pacman -S cmake

# Homebrew
brew install cmake

2. Clone the repository and cd into it.

git clone --recurse-submodules https://github.com/RangHo/webrtc-delay-estimation
cd webrtc-delay-estimation

3. Create a build directory and build.

mkdir build && cd build
cmake ..
cmake --build . --target webrtc-delay-estimation

How to use

This repository provides 3 CMake targets as follows:

• webrtc-delay-estimation: A static library exposing delay estimation function as declared in include/webrtc-delay-estimation.h
• delay-estimator: An executable that uses the library above to estimate delay in between two WAV files
• webrtc-delay-estimation-tests: A testing executable that generates random samples and tries to estimate delay using them

webrtc-delay-estimation library

This library exposes the extracted WebRTC components and an additional helper function. By default, linking this library using CMake's target_link_libraries directive includes definition for the helper function only. To access raw WebRTC components, copy the relevant .h files from src/ directory.

Example CMakeLists.txt file would look like:

add_executable (my-executable
  "main.cc"
  # ...
)

target_link_libraries (my-executable PRIVATE
  webrtc-delay-estimation
)

delay-estimator binary

This command line utility uses webrtc-delay-estimation library above to find delay from two different WAV files. Unless given a -v switch, the program will write the estimated delay in samples to stdout. It takes two positional arguments: render and capture. The former is the WAV file of the far end, and the latter is the WAV file captured by the local microphone.

Usage

delay-estimator [-hv] [-f integer] [-d {2,4,8}] /path/to/render /path/to/capture

Argument information

• (required, positional) /path/to/render: path to the render WAV file.
• (required, positional) /path/to/capture: path to the capture WAV file.
• (optional) -h or --help: displays help message.
• (optional) -v or --verbose: show additional information when executing the program.
• (optional) -f integer or --filter integer: Use integer number of filters when estimating delay. (default: 10)
• (optional) -d {2,4,8} or --downsampling-factor {2,4,8}: sets the down sampling factor. The factor can be either 2, 4, or 8. (default: 8)

webrtc-delay-estimation-tests binary

This target builds a testing binary using Catch2 testing framework. Build and run the binary to test the functionality of the library.

# You can run the binary directly
cd build/tests
./webrtc-delay-estimation-tests

# ... or you can just use ctest to automate things
ctest