Note: In September 2021, the GStreamer project merged all its git repositories into a single, unified repository, often called monorepo. The build system referred in this post as "gst-build" is now in the root of this combined/mono repository.

Earlier this week, WebRTC became an official W3C and IETF standard for enabling real time communication (RTC) between browsers and other mobile applications via a set of simple APIs. GStreamer has a powerful and rapidly maturing WebRTC implementation. So, the obvious question is: how do we build this on Windows?

There are two ways of building GStreamer on Windows - either with cerbero or gst-build. For a simple GStreamer install with WebRTC support, cerbero will just work out of the box. However, for a more flexible solution that builds significantly faster, we use gst-build. Unfortunately, it's not just a matter of using gst-build. You also need the OpenSSL dependency so that gst-build will build the WebRTC element.

Here's how to add this support:

OpenSSL

If you haven't already followed my previous guide on GStreamer and Windows, please follow the steps there to build GStreamer from source.

Next, we will need to clone and build OpenSSL

1. Install 64 bit Strawberry Perl
2. Delete Strawberry Perl path entries from system path
3. Install 64 bit NASM
4. Enter the NASM install directory on your Windows PATH
5. git clone https://github.com/openssl/openssl.git
6. Open 64 bit VS command shell as Administrator
7. build OpenSSL using steps below (this could take a while). Note: we set c:/bin/OpenSSl as our OpenSSL install directory, but this is easily changed to the directory of your choice.

> cd openssl
> set PATH=%PATH%;C:\Strawberry\c\bin;C:\Strawberry\perl\site\bin;C:\Strawberry\perl\bin
> perl Configure VC-WIN64A --prefix=c:/bin/OpenSSL
> nmake
> nmake test
> nmake install

Now, download the OpenSSL pkg-config folder here and place it in the lib directory of your OpenSSL install directory.

Next, we need to add the OpenSSL install directory to the PKG_CONFIG_PATH environment variable that we set in my previous post:

Set PKG_CONFIG_PATH equal to %GSTREAMER_1_0_ROOT_X86_64%lib\pkgconfig;C:\bin\OpenSSL\lib\pkg-config

We also need to add the OpenSSL bin directory C:\bin\OpenSSL\bin to the Windows path.

And finally, we open a new 64 bit VS command shell and execute the following:

> cd %SOURCE_DIR%gst-build
> meson build --reconfigure --prefix=%GSTREAMER_1_0_ROOT_X86_64% -Dtls=disabled -Ddevtools=disabled && ninja -C build install

And now:

> gst-inspect-1.0 webrtcbin

should find the webrtcbin plugin!

If you have any questions about GStreamer WebRTC support on Windows or any other platform, please contact us!