asio-rtc

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A fresh WebRTC implementation built on C++23, Boost.Asio, and stdexec.

When to use asio-rtc

If your project uses Boost.Asio and needs to establish WebRTC connections with browsers or SFU servers, asio-rtc is a great fit because:

• asio-rtc has no internal threads; all logic runs on an executor.
• asio-rtc supports both the traditional asio async model and the C++26 Senders/Receivers model.
• asio-rtc provides JavaScript-like interfaces; if you are familiar with browser WebRTC, asio-rtc will feel familiar.
• All async operations support cancellation.
• The code is readable and easy to modify.

Current Progress

• PeerConnection — offer/answer, ICE, DTLS-SRTP, SCTP DataChannel
• Transceiver — add_transceiver, get_transceivers, replace_track
• DataChannel — RFC 8832 DCEP over SCTP-over-DTLS
• SDP — parse/generate, BUNDLE, codec negotiation, extmaps
• Jitter buffer — RTP reorder and frame assembly
• NACK — packet loss retransmission
• TWCC — TWCC receive-side feedback
• mDNS
• Trickle-ICE
• ICE-Lite Client Side
• ICE-Lite Server Side
• GCC — TWCC send-side congestion control
• Bandwidth estimation — REMB send/receive
• Simulcast
  • send
  • recv
• FEC — RED, ULPFEC
• Renegotiation
• DTMF sender
• Audio PLC
• TCP candidate
• TURN
  • UDP
  • TCP
  • TLS
• asio completion token compatible interfaces
• Browser interop test suite

Dependencies

Dependency	Version	Notes
Boost (headers only)	1.89+	boost.container, boost.intrusive, etc.; required even with standalone Asio
stdexec	—	std::execution reference implementation
OpenSSL	3.0+	DTLS/SCTP
asio-ice	git submodule	ICE/DTLS/SCTP transport layer
libsrtp	git submodule	SRTP encryption
Clang / GCC / MSVC	20+ / 13+ / 19+	C++23

Build

git clone --recurse-submodules https://github.com/SamGaaWaa/asio-rtc.git
./debug-build.sh          # Clang 20 debug + ASan → clang-build/

Or manually:

mkdir build && cd build
cmake .. -DCMAKE_BUILD_TYPE=Debug \
         -DBoost_DIR=/path/to/boost/lib/cmake/Boost-1.91.0 \
         -DSTDEXEC_DIR=/path/to/stdexec/include
make -j$(nproc)

CMake option	Default	Description
ASIORTC_USE_STANDALONE_ASIO	OFF	Use standalone Asio instead of Boost.Asio (still requires other Boost headers)
ASIORTC_TEST	ON	Build tests

Usage

All async interfaces are available in two forms:

• Sender interface (default): returns a stdexec sender, which can be co_awaited in coroutines, or composed with algorithms like stdexec::then / stdexec::when_all / exec::async_scope.
• Completion token interface: methods additionally accept an asio completion token (use_awaitable, use_future, deferred, use_sender, plain callbacks, etc.), allowing co_await in asio coroutines or composition with other completion tokens.

#include "asiortc.hpp"

namespace rtc = asiortc;

boost::asio::io_context ctx;

rtc::peer_connection conn(ctx.get_executor(), rtc::configuration{
    .ice_servers = {.urls = {"stun:stun.l.google.com:19302"}}
});

auto tr = conn.add_transceiver(
    rtc::media_description::make_default(rtc::media_format::vp8),
    {.direction = rtc::sdp_direction::sendrecv, .streams = {"my-video"}});

co_await conn.set_remote_description(parse_sdp(browser_offer, "offer"));
auto answer = co_await conn.create_answer();
co_await conn.set_local_description(std::move(answer));

Both interface styles:

// sender interface: co_await directly in a stdexec coroutine
rtc::task<void> f(rtc::peer_connection &conn) {
    auto offer = co_await conn.create_offer();
}

// completion token interface: co_await in an asio coroutine
boost::asio::awaitable<void> g(rtc::peer_connection &conn) {
    auto offer = co_await conn.create_offer(boost::asio::use_awaitable);
}

Examples

Example	Description
chat	SDP exchanged via copy-paste, DataChannel chat
sfu	Browser video SFU loopback
test	Browser UI-driven negotiation test

Tests

cd clang-build
./srtp_test
./rtp_rtcp_test
./sdp_test
./any_stream_track_test ../test.webm   # needs ASIORTC_ENABLE_FFMPEG=ON

asio-rtc draws on the following implementations

• aiortc
• libdatachannel
• pion/webrtc

License

MIT

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🚧 This project is under heavy development. Bug reports, feature suggestions, and pull requests are welcome!