MOQ Plugin

Introduction

This is an OpenMOQ plugin for OBS that streams video over MOQ, using openmoq/moq5 as the underlying protocol implementation.

This project is under active development. It may contain bugs, and several features are still in progress or not yet implemented. See the Roadmap section below for what's currently missing.

Dependencies

• libmoq (openmoq/moq5), MOQ protocol implementation, built with the service component. Must be built from the qualabs/moq5 fork, whose codec-signaling work is proposed upstream as PR #5 (see Required libmoq fork below).
• OBS Studio fork with dynamic service registration, required to use this plugin (see Required OBS fork below).
• CMake 3.28+
• A C++ compiler with C++17 support (GCC 13+, Clang, or MSVC)

Required OBS fork

To use this plugin, OBS Studio needs support for dynamically detecting services registered by plugins. That support is currently in review as obs-studio PR #12911, and is being considered for inclusion in the v33.0 release (not guaranteed).

Until that PR is merged, you'll need to build OBS Studio from that PR's branch/fork to be able to select and configure this plugin's service from the OBS UI.

Required libmoq fork

This plugin currently requires a fork of libmoq (openmoq/moq5): qualabs/moq5, whose codec-signaling helpers and sized config initializers are proposed upstream as PR #5. The plugin will not build against upstream moq5 as-is.

git clone https://github.com/qualabs/moq5.git
cd moq5

Then follow the build steps below from that checkout. The revision CI builds against is pinned in .github/scripts/.libmoq-version and it is temporarily the fix/hevc-temporal-sublayers branch.

Building libmoq (openmoq/moq5)

This plugin links against libmoq (openmoq/moq5) (find_package(libmoq REQUIRED COMPONENTS service)). libmoq must be built and installed on the system before configuring this plugin.

1. Build and install libmoq

libmoq's picoquic-backed adapters (MOQ_BUILD_PQ_THREADED, used by the service tier here) need picoquic's private picoquic_internal.h, which picoquic does not install. Because of that, libmoq must be built in "source-tree mode": pointed at a picoquic source checkout plus a built picotls, rather than at any picoquic already installed on the system.

# Fetch pinned picoquic + picotls sources and build picotls.
# Prints (and writes to .deps/picoquic-ci/picoquic_deps.env) the two paths
# needed below.
scripts/setup_picoquic_deps.sh

cmake -S . -B build \
  -DCMAKE_BUILD_TYPE=RelWithDebInfo \
  -DMOQ_BUILD_SERVICE=ON \
  -DMOQ_BUILD_MSF=ON \
  -DMOQ_BUILD_MEDIA_OBJECT=ON \
  -DMOQ_BUILD_ADAPTER_PICOQUIC=ON \
  -DMOQ_BUILD_PQ_THREADED=ON \
  -DMOQ_BUILD_TESTS=OFF \
  -DCMAKE_INSTALL_PREFIX=/usr/local \
  -DMOQ_PICOQUIC_SOURCE_DIR="$(pwd)/.deps/picoquic-ci/picoquic" \
  -DMOQ_PICOTLS_PREFIX="$(pwd)/.deps/picoquic-ci/picotls/build"

cmake --build build -j"$(nproc)"
cmake --install build

2. Configure this plugin against libmoq

Because libmoq was built in source-tree mode, anything that consumes it via find_package(libmoq), including this plugin, re-triggers the same picoquic resolution (libmoqConfig.cmake calls find_dependency(Picoquic)). So this plugin's own configure needs the same two picoquic variables, and needs OBS's default warnings-as-errors disabled.

cmake -S . -B build \
  -DMOQ_PICOQUIC_SOURCE_DIR=</path/to/moq5/>.deps/picoquic-ci/picoquic \
  -DMOQ_PICOTLS_PREFIX=</path/to/moq5/>.deps/picoquic-ci/picotls/build \
  -DCMAKE_COMPILE_WARNING_AS_ERROR=OFF

cmake --build build -j"$(nproc)"

Building in CI

CI does the same thing automatically: .github/scripts/build-libmoq builds and installs libmoq into .moq-deps/libmoq/prefix at the revision pinned in .github/scripts/.libmoq-version, then exports MOQ_PICOQUIC_SOURCE_DIR, MOQ_PICOTLS_PREFIX and CMAKE_PREFIX_PATH for the plugin build that follows. To move to a different libmoq, change MOQ5_REF there to a commit SHA or a branch name; the build cache is keyed on the SHA it resolves to, so tracking a branch still picks up new commits.

On macOS the plugin is a universal binary, so libmoq and picotls are built for both arm64 and x86_64 in a single pass. OpenSSL cannot be built that way, its build system handles one architecture per tree, and neither obs-deps (mbedtls only) nor Homebrew (single-arch) ships a universal one, so .github/scripts/build-openssl-macos builds each slice separately and lipos the static archives together. It runs before build-libmoq and exports OPENSSL_ROOT_DIR. OpenSSL is linked statically, so the plugin carries no Homebrew runtime dependency.

The Windows job is disabled (if: false) until libmoq is built there too.

Installing the built plugin

Copy the resulting shared object into your OBS install's plugin directory, e.g.:

cp build/obs-moq.so </path/to/obs-install>/lib/x86_64-linux-gnu/obs-plugins/

Usage

1. Select the MOQ service in OBS's stream settings.
2. In the Server field, enter the URL of the MOQ relay you want to publish to.
3. In the Stream Key field, enter the MOQ namespace, with each namespace tuple part separated by a dash (-). For example, a namespace of ["live", "user123"] would be entered as live-user123.

Tested against

This plugin has been, and continues to be, tested using:

• moqx
• moq-playa

Roadmap

The plugin currently only supports H.264 video. Planned next steps:

• Add support for audio tracks (AAC, Opus, AC-3)
• Add support for other video/audio codecs (HEVC, AV1)
• Add CMAF support
• Achieve a lower latency target