Reliable Internet Stream Transport (RIST) is an
open-source
Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use and view the source code, design documents, or content of the product. The open source model is a decentrali ...
, open-specification transport
protocol
Protocol may refer to:
Sociology and politics
* Protocol (politics)
Protocol originally (in Late Middle English, c. 15th century) meant the minutes or logbook taken at a meeting, upon which an agreement was based. The term now commonly refers to ...
designed for reliable transmission of video over
lossy networks (including
the Internet
The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a network of networks that consists of private, publ ...
) with low latency and high quality. It is currently under development in the
Video Services Forum's "RIST Activity Group."
RIST is intended as a more reliable successor to
Secure Reliable Transport
Secure Reliable Transport (SRT) is an open source video transport protocol that utilises the UDP transport protocol. The SRT Protocol specification is available as an Internet Draft from the IETF.
Overview
SRT provides connection and con ...
, and as an open alternative to proprietary commercial options such as ActionStreamer, Zixi, VideoFlow, QVidium, and DVEO (Dozer).
Technology
Technically, RIST seeks to provide reliable, high performance media transport by using
RTP /
UDP at the transport layer to avoid the limitations of
TCP. Reliability is achieved by using NACK-based retransmissions (
ARQ). SMPTE-2022
Forward Error Correction
In computing, telecommunication, information theory, and coding theory, forward error correction (FEC) or channel coding is a technique used for controlling errors in data transmission over unreliable or noisy communication channels.
The centra ...
can be combined with RIST but is known to be significantly less effective than ARQ.
RIST Simple Profile
was published in October 2018 and includes the following features:
* The base stream uses RTP for compatibility with existing equipment.
* Retransmission requests use
RTCP
The RTP Control Protocol (RTCP) is a binary-encoded out-of-band signaling protocol that functions alongside the Real-time Transport Protocol (RTP). RTCP provides statistics and control information for an RTP session. It partners with RTP in th ...
. Two types of retransmission requests are defined:
** A Bitmask NACK, defined in RFC 4585.
** A Range NACK, defined as an APP RTCP packet.
*
Bonding of multiple links for load sharing.
* Seamless switching using SMPTE-2022-7.
*Out-of-band transmission of protection data.
The RIST AG is working on an update to RIST Simple Profile that adds link probing to allow for dynamic ARQ protection.
RIST Main Profile
was published in March 2020 and adds the following features to Simple Profile:
* Tunneling based on RFC 8086, with bidirectional send/receive in the same tunnel.
*Multiplexing of multiple streams into the same tunnel.
*In-band data support in the tunnel, useful for remote management.
*Client/Server architecture.
*Firewall traversal.
*
DTLS
Datagram Transport Layer Security (DTLS) is a communications protocol providing security to datagram-based applications by allowing them to communicate in a way designed to prevent eavesdropping, tampering, or message forgery. The DTLS protocol ...
encryption.
* Pre-Shared Key encryption, with multicast support, access control, and authentication.
*Advanced authentication options using either
public key certificate
In cryptography, a public key certificate, also known as a digital certificate or identity certificate, is an electronic document used to prove the validity of a Key authentication, public key. The certificate includes the public key and informati ...
s or
TLS-SRP Transport Layer Security Secure Remote Password (TLS-SRP) ciphersuites are a set of cryptographic protocols that provide secure communication based on passwords, using an SRP password-authenticated key exchange.
There are two classes of TLS-SRP ...
.
* Bandwidth optimization based on NULL packet deletion.
* Support for high bit-rate streams by extending the RTP sequence number.
The RIST AG has defined a number of Main Profile compliance levels. Approval of this document is expected soon.
RIST Advanced Profile was published in 2022 and updated in 2023.
VideoFlow has provided IPR that covers both Simple Profile and Main Profile under
RAND-Z
Reasonable and non-discriminatory (RAND) terms, also known as fair, reasonable, and non-discriminatory (FRAND) terms, denote a voluntary licensing commitment that standards organizations often request from the owner of an intellectual property r ...
terms.
Open source implementations and tools
libRIST an open-source RIST implementation that includes both Simple and Main Profiles.
GStreamerplugin for RIST
UpipeWireShark dissector for RIST
References
{{reflist
Multimedia
Network protocols