RIST Library Overview

bilbycast-rist is a pure-Rust implementation of the RIST (Reliable Internet Stream Transport) protocol for professional broadcast media transport. It wraps standard RTP/RTCP with automatic retransmission (ARQ) to recover lost packets over lossy IP networks — internet, satellite, cellular — without the latency penalty of FEC-only approaches.

Zero C/C++ dependencies. Wire-verified against librist 0.2.11 (Simple Profile), and interoperable with FFmpeg rist:// and GStreamer ristenc/ristdec.

Features

• No external system libraries — builds with cargo build alone
• Wire-verified — 100% bidirectional interop with librist 0.2.11 Simple Profile
• NACK-based ARQ — receiver detects gaps and requests retransmission
• RTT-aware timing — NACK scheduling adapts to measured round-trip time
• Dual-port RTP/RTCP — standard even/odd port pair (RFC 3550)
• SMPTE 2022-7 bonding — hitless merge across redundant network paths
• Low, bounded latency — configurable receiver buffer (typically 100–2000 ms)
• Async I/O — Built on Tokio, lock-free data path

Workspace Structure

bilbycast-rist/
  rist-protocol/    # Pure protocol logic (no I/O, no async runtime)
  rist-transport/   # Async I/O layer (tokio-based networking)

Crate	Use When
rist-protocol	Building a custom transport or embedding RIST logic — packet parsing/serialisation, RTCP state machines, NACK tracking, RTT estimation, bonding merger. No I/O dependencies.
rist-transport	Building Rust applications that need RIST — tokio-based sender/receiver tasks, dual-port UDP channels, public RistSocket API.

Quick Start

use rist_transport::{RistSocket, RistSocketConfig};
use bytes::Bytes;

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    // --- Sender ---
    let config = RistSocketConfig {
        local_addr: "0.0.0.0:6010".parse()?,
        ..Default::default()
    };
    let sender = RistSocket::sender(config, "10.0.0.2:6000".parse()?).await?;
    sender.send(Bytes::from_static(&[0x47, 0x00, 0x00, 0x10])).await?;

    // --- Receiver ---
    let config = RistSocketConfig {
        local_addr: "0.0.0.0:6000".parse()?,
        ..Default::default()
    };
    let mut receiver = RistSocket::receiver(config).await?;
    while let Some(payload) = receiver.recv().await {
        // payload is the raw MPEG-TS data (no RTP header)
        println!("received {} bytes", payload.len());
    }
    Ok(())
}

Specifications

Spec	Title	Status
TR-06-1:2020	RIST Simple Profile	Implemented
TR-06-2:2024	RIST Main Profile	Types stubbed (GRE-over-UDP, DTLS, AES-CTR, null-packet deletion — dedicated follow-up sprints)
RFC 3550	RTP: A Transport Protocol for Real-Time Applications	Implemented
RFC 4585	Extended RTP Profile for RTCP-Based Feedback (AVPF)	Implemented (Generic NACK)

Interoperability

Tested against librist 0.2.11 (Simple Profile, -p 0) under adverse-network conditions (10% loss / 200 ms delay / 50 ms jitter on both RTP and RTCP paths):

Direction	Rate	Delivery
librist ristsender → bilbycast receiver	5 Mbps	100%
librist ristsender → bilbycast receiver	50 Mbps	100%
bilbycast sender → librist ristreceiver	5 Mbps	100% (stats-verified)
bilbycast sender → librist ristreceiver	50 Mbps	99.996%

In bilbycast-edge

RIST is an always-compiled, first-class input and output protocol in bilbycast-edge — there is no feature flag to enable it. The edge integration is wire-verified against the full librist 0.2.11 ARQ matrix in both directions.

See the Usage Guide for embedding the library, and the Protocol Reference for wire formats and state-machine detail.