EN 62676-2-1:2014

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Video nadzorni sistemi za varnostne aplikacije - 2-1. del: Protokoli video prenosa - Splošne zahteve (IEC 62676-2-1:2013)Systèmes de video surveillance appliqués à la sécurité - Part 2-1: Protocoles de transmission video - Exigences généralesVideo surveillance systems for use in security applications - Part 2-1: Video transmission protocols - General requirements33.160.40Video sistemiVideo systems13.320Alarmni in opozorilni sistemiAlarm and warning systemsICS:Ta slovenski standard je istoveten z:EN 62676-2-1:2014SIST EN 62676-2-1:2014en01-marec-2014SIST EN 62676-2-1:2014SLOVENSKI
STANDARD
EUROPEAN STANDARD EN 62676-2-1 NORME EUROPÉENNE
EUROPÄISCHE NORM January 2014
CENELEC European Committee for Electrotechnical Standardization Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B - 1000 Brussels
© 2014 CENELEC -
All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 62676-2-1:2014 E
ICS 13.320
English version
Video surveillance systems for use in security applications -
Part 2-1: Video transmission protocols -
General requirements (IEC 62676-2-1:2013)
Systèmes de vidéosurveillance destinés à être utilisés dans les applications de sécurité -
Part 2-1: Protocoles de transmission vidéo -
Exigences générales (CEI 62676-2-1:2013)
Videoüberwachungsanlagen für Sicherungsanwendungen – Teil 2-1: Videoübertragungsprotokolle – Allgemeine Anforderungen (IEC 62676-2-1:2013)
This European Standard was approved by CENELEC on 2013-12-12. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Foreword The text of document 79/435/FDIS, future edition 1 of IEC 62676-2-1, prepared by IEC TC 79 "Alarm and electronic security systems" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN 62676-2-1:2014. The following dates are fixed: • latest date by which the document has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2014-09-12 • latest date by which the national standards conflicting with the document have to be withdrawn (dow) 2016-12-12
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent rights. Endorsement notice The text of the International Standard IEC 62676-2-1:2013 was approved by CENELEC as a European Standard without any modification. In the official version, for Bibliography, the following note has to be added for the standard indicated: IEC 62676-1-1 NOTE
Harmonised as EN 62676-1-1. SIST EN 62676-2-1:2014

- 3 - EN 62676-2-1:2014 Annex ZA
(normative)
Normative references to international publications with their corresponding European publications
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
NOTE
When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies.
Publication Year Title EN/HD Year IEC 62676-1-2 - Video surveillance systems for use in security applications -
Part 1-2: Video transmission – General video transmission - requirements EN 62676-1-2 -
IEC 62676-2-2 - Video surveillance systems for use in security applications -
Part 2-2: Video transmission protocols - IP interoperability implementation based on HTTP and REST services EN 62676-2-2 -
IEC 62676-2-3 - Video surveillance systems for use in security applications -
Part 2-3: Video transmission protocols - IP interoperability implementation based on WEB services EN 62676-2-3 -
IETF RFC 2326 1998 Real time Streaming protocol (RTSP)
IETF RFC 3550 - A Transport Protocol for Real-Time Applications - -
IETF RFC 3984 - RTP Payload Format for H.264 Video - -
IETF RFC 4566 - SDP: Session Description Protocol - -
IETF RFC 3016 - RTP Payload Format for MPEG-4 Audio/Visual Streams - -
IETF RFC 4571 - Framing Real-time Transport Protocol (RTP) and RTP Control Protocol (RTCP) Packets over Connection-Oriented Transport - -
IETF RFC 3551 - RTP Profile for Audio and Video Conferences with Minimal Control - -
IEC 62676-2-1 Edition 1.0 2013-11 INTERNATIONAL STANDARD NORME INTERNATIONALE Video surveillance systems for use in security applications –
Part 2-1: Video transmission protocols – General requirements
Systèmes de vidéosurveillance destinés à être utilisés dans les applications de sécurité –
Partie 2-1: Protocoles de transmission vidéo – Exigences générales
INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE W ICS 13.320 PRICE CODE CODE PRIX ISBN 978-2-8322-1181-6
– 2 – 62676-2-1 © IEC:2013 CONTENTS FOREWORD . 4 INTRODUCTION . 6 1 Scope . 7 2 Normative references . 7 3 Terms, definitions and abbreviations . 8 3.1 Terms and definitions . 8 3.2 Abbreviations . 15 4 Video transmission network architecture . 16 4.1 General . 16 4.2 Networking and connectivity . 17
General . 17 4.2.1 Network streaming performance: quality of service . 18 4.2.24.3 Device discovery and description . 18 4.4 Video media types and payload formats . 18 4.5 Video transport . 18 4.6 Eventing and health check . 18 5 The building block of existing standards . 19 6 VSS device model . 19 6.1 Overview . 19 6.2 Device model elements . 20 7 General IP interoperability requirements . 21 7.1 General . 21 7.2 General protocol requirements overview . 21 7.3 General high level IP video interface and protocol requirements . 21
General . 21 7.3.1 Versioning, capability exchange, and extensibility requirements . 22 7.3.2 Implementations . 22 7.3.37.4 Non-conformance video transmission systems and devices . 22 7.5 Mandatory documentation for the IP video interface of a VTD . 22 7.6 Video and data transport: mandatory streaming requirements . 24 7.7 Overview . 24 8 Live streaming . 25 8.1 General . 25 8.2 Media stream protocol . 25
Transport format . 25 8.2.1 Media transport . 25 8.2.2 Synchronization point . 27 8.2.38.3 Media control protocol . 28
Stream control . 28 8.3.1 RTSP . 28 8.3.2 Keep-alive method for RTSP session . 29 8.3.3 RTSP audio and video synchronization . 30 8.3.4 RTSP message example . 31 8.3.58.4 Error handling . 32 9 Playback . 32 9.1 General . 32 SIST EN 62676-2-1:2014

62676-2-1 © IEC:2013 – 3 – 9.2 RTP header extension . 32 10 Device discovery and description. 32 11 Eventing requirements . 32 Bibliography . 34
Figure 1 – Overview IP Video standard protocol . 17 Figure 2 – Functional protocol layers . 17 Figure 3 – Building block of existing standards . 19 Figure 4 – VTD example network . 20 Figure 5 – Layer structure . 24 Figure 6 – RTCP sequence . 26 Figure 7 – RTCP sender report . 27 Figure 8 – Media synchronization. 27 Figure 9 – Stream control . 28 Figure 10 – Keep alive . 30
Table 1 – RTSP methods . 29
– 4 – 62676-2-1 © IEC:2013 INTERNATIONAL ELECTROTECHNICAL COMMISSION ____________
VIDEO SURVEILLANCE SYSTEMS FOR USE
IN SECURITY APPLICATIONS –
Part 2-1: Video transmission protocols –
General requirements
FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations. 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international consensus of opinion on the relevant subjects since each technical committee has representation from all interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user. 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications. Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter. 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any services carried out by independent certification bodies. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 62676-2-1 has been prepared by IEC technical committee 79: Alarm and electronic security systems. The text of this standard is based on the following documents: FDIS Report on voting 79/435/FDIS 79/448/RVD
Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. A list of all parts in the IEC 62676 series, published under the general title Video surveillance systems for use in security applications, can be found on the IEC website. SIST EN 62676-2-1:2014

62676-2-1 © IEC:2013 – 5 – The committee has decided that the contents of this publication will remain unchanged until the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to the specific publication. At this date, the publication will be
• reconfirmed, • withdrawn, • replaced by a revised edition, or • amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates that it contains colours which are considered to be useful for the correct understanding of its contents. Users should therefore print this document using a colour printer.
– 6 – 62676-2-1 © IEC:2013 INTRODUCTION The IEC Technical Committee 79 in charge of alarm and electronic security systems together with many governmental organisations, test houses and equipment manufacturers have defined a common framework for video surveillance transmission in order to achieve interoperability between products.
The IEC 62676 series of standards on video surveillance system is divided into 4 independent parts: Part 1:
System requirements Part 2:
Video transmission protocols Part 3:
Analog and digital video interfaces Part 4: Application guidelines (to be published) Each part has its own clauses on scope, references, definitions and requirements. This IEC 62676-2 series consists of 3 subparts, numbered parts 2-1, 2-2 and 2-3 respectively: IEC 62676-2-1, Video transmission protocols – General requirements
IEC 62676-2-2, Video transmission protocols – IP interoperability implementation based on HTTP and REST services IEC 62676-2-3, Video transmission protocols – IP interoperability implementation based on Web services The first subpart of this IEC 62676-2 series defines protocol requirements to be fulfilled by any high-level IP video device interface. The following two parts – Part 2-2 and Part 2-3 – define two alternative protocols, one is based on HTTP and REST services and the second is based on Web Services. It is based on the general requirements for video transmission of IEC 62676-1-2, which defines minimum IP connectivity requirements, basic video streaming, stream control, eventing, discovery and description functions. The purpose of the transmission system in a video surveillance system installation is to provide reliable transmission of video signals between the different types of Video Surveillance System (VSS) so far called CCTV equipment in security, safety and monitoring applications. Today VSS reside in security networks using IT infrastructure, equipment and connections within the protected site itself.
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IN SECURITY APPLICATIONS –
Part 2-1: Video transmission protocols –
General requirements
1 Scope This part of IEC 62676 introduces an IP network interface for devices in surveillance applications. This International Standard specifies a network protocol for the full interoperability of video devices. On top of the basic layers protocols are defined to accomplish the full interoperability of video devices. In surveillance applications IP video devices have to use standardized protocols to accomplish following functionality: video streaming, stream control, event handling, discovery, capability description, device management, PTZ control, auxiliaries and other functions. Some areas of this transmission standard are covered by more than one approach, e.g. ZeroConf and WS-Discovery. The network protocols recommended and defined by this video transmission standard are selected with a sense for future relevance and further extensions.
Video transmission equipment may be combined with additional functions, e.g. for audio or metadata transmission.
2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 62676-1-2, Video surveillance systems for use in security applications – Part 1-2: System requirements – Performance requirements for video transmission
IEC 62676-2-2, Video surveillance systems for use in security applications – Part 2-2: Video transmission protocols – IP interoperability implementation based on HTTP and REST services IEC 62676-2-3, Video surveillance systems for use in security applications – Part 2-3: Video transmission protocols – IP interoperability implementation based on web services IETF RFC 2326:1998, Real Time Streaming Protocol (RTSP) IETF RFC 3016, RTP Payload Format for MPEG-4 Audio-Visual Streams
IETF RFC 3550, A transport protocol for Real-Time Applications (Replaces RFC 1889) IETF RFC 3550, Standard 64, RTP: A Transport Protocol for Real-Time Applications IETF RFC 3551, Profile for audio and video conferences with minimal control (Replaces RFC890) SIST EN 62676-2-1:2014

– 8 – 62676-2-1 © IEC:2013 IETF RFC 3551, Standard 65, RTP Profile for Audio and Video Conferences with Minimal Control
IETF RFC 3984, RTP payload format for H.264/AVC IETF RFC 4566, SDP: Session Description Protocol IETF RFC 4571, Framing Real-time Transport Protocol and RTP Control Protocol [RTCP] Packets over Connection-Oriented Transport 3 Terms, definitions and abbreviations 3.1 Terms and definitions For the purposes of this document, the following terms and definitions apply.
3.1.1analog
a form of information that is represented by a continuous and smoothly varying amplitude or frequency changes over a certain range
3.1.2analog video video signal made of a continuous electrical signal
3.1.3application program interface a set of
interfaces for developers to interact with a component or application
3.1.4bandwidth property of
networks to describe the amount of data that can be carried from one point in the network to another in a given time period, usually a second, affected in video surveillance by frame rate, image resolution, compression ratio, image noise, complexity detail of a monitored scene
3.1.5capability a named piece of functionality (or feature) that is declared as supported or requested by an agent
3.1.6capturing process of transferring video from one source to another for use on a digital video device, network or storage, e.g. conversion of analog to digital
3.1.7channel one or more streams of video, audio and/or metadata that together constitute a unique entity for the purpose of surveillance
3.1.8client a software application or other entity that uses the services offered by a Video Transmission Device (VTD) SIST EN 62676-2-1:2014

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3.1.9codec abbreviation of compression/decompression algorithm, used to encode and decode, or compress and decompress data, such as video
3.1.10component a software or hardware object, meant to interact with other components, encapsulating certain functionality or a set of functionalities with clearly defined interfaces and conforming to a prescribed behavior common to all components within a standard
3.1.11device description formal definition of a network device, expressed in XML syntax, specified by a vendor
3.1.12digital information coded in discrete, separate pulses or signal levels
3.1.13digital video recorder
DVR network video device recording multiple analog video channels onto a hard disk in digital format, which allows viewing, replay and management remotely via a VT client
3.1.14discovery act of locating a network device or machine-processable description of a service-related resource that may have been previously unknown and that meets certain functional criteria
3.1.15DNS
domain name system protocol that enables hierarchical naming system in a network for identification and resolving symbolic names such as domain or computer names for example translate http://Videoserver1 or www.upnp.org into IP addresses
3.1.16DTD
document type definition document defining the format of the contents presented between the tags in an XML document, and the way they should be interpreted by the application reading the XML document
3.1.17dynamic host configuration protocol
DHCP protocol to automatically provide IP addresses and other network configuration information to network nodes
3.1.18event notification of one or more changes in state variables sent by a network device
3.1.19eventing the exchange of specially-formatted messages describing events of a event server e.g network device SIST EN 62676-2-1:2014

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3.1.20frame full frame of video as acquired in progressive mode or as combination of two image fields interlaced together
3.1.21identifier
code associated with each object which uniquely identifies the object e.g. for SNMP in the global tree of objects
3.1.22IETF
Internet engineering task force standards body that forms Working Groups to develop technology for the Internet community
3.1.23I-frame independent frame coded as intraframe of an image sequence of differential coded frames
3.1.24Internet protocol
IP basic connectionless network-layer protocol
3.1.25IP camera device capturing and transmitting live video images over an IP network allowing remote viewing, recording, and management
3.1.26Internet protocol video
IP video transmission of video signals over an IP network: representation of sequential image information in digital (discrete level) formats that are transferred using IP data packets (datagrams) including associated protocols for discovery, description, streaming, stream control, eventing, control and configuration of video network devices
3.1.27IP video Interface software point of communication for IP video between a device and the network
3.1.28IP video Network collection of video transmission devices connected to each other allowing to communicate with each other, share resources and information over a variety of connection protocols
3.1.29interoperability ability of communication of systems and units to provide services and to accept services from other systems and units, in order to use the services for efficient operation;
ability for information or services to be exchanged directly and smoothly between providers and consumers
3.1.30jitter variation in a network delay that is perceived by the receiver of each packet SIST EN 62676-2-1:2014

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3.1.31latency delay in the response of far end participants, often a result of network congestion and geographic distance
3.1.32link
relationship between two network nodes when one resource refers to the other resource e.g. by the means of a URI
3.1.33message the basic unit of communication containing the data to be transmitted between network nodes such as client and server
3.1.34messaging exchange of messages, which are specially formatted data packets, describing events, commands, status information, requests, replies, etc of a messaging source to a subscribing or listening client
3.1.35moving picture experts group
MPEG
working committee that defines and develops industry standards for digital video systems, specifying the data compression and decompression processes and how they are delivered on digital video systems Note 1 to entry: This note applies to the French language only.
3.1.36network architecture framework and technology foundation for the design, building and managing of a communication network, typically in a layered structure dividing the communication tasks into a number of smaller parts, each part accomplishing a particular sub-task and interacting with the other parts in a small number of well-defined ways
3.1.37network connectivity physical (wired or wireless) and logical (protocol) connection of multiple devices or a single device to a network, such as a IP video network
3.1.38network interfaces point of communication between a device and the network
3.1.39network node grouping of one or more network components which provides network related functions, administered as a single entity
3.1.40network protocol defined rules and procedures for the network communications SIST EN 62676-2-1:2014

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3.1.41network video recorder
NVR network video device recording multiple video streams onto a hard disk in digital format, which allows viewing, replay and management remotely via a VT client
3.1.42OASIS
organization for the advancement of structured Information standards a nonprofit, international consortium whose goal is to promote the adoption of product-independent standards for information formats such as Extensible Markup Languages (XML), Hypertext Markup Language (HTML) etc.
3.1.43open systems interconnection
OSI complete suite of network routing protocols developed by ISO including routing protocols between the different layers of the system
3.1.44payload
true message data itself without protocol information
3.1.45principle
fundamental rule applicable to a large number of situations and variations
3.1.46protocol error result and answer of an incorrectly formed protocol message, which may consist of illegal header values or payload, received unexpectedly or after a certain timeout EXAMPLES: HTTP and RTSP define a set certain of standard status codes to notify about protocol errors.
3.1.47quality of service
QoS software-based ability to guarantee the required level of network resources for real-time video traffic;
a major performance indicator for networks especially for devices such as IP cameras, access control, and building management or security systems
3.1.48recording a single container for a set of video, audio and metadata tracks with an endless timeline holding data at certain time frames or gaps without any information from any kind of real-time video source or input including associated non-video data stored on any kind of media
3.1.49representation
data about the actual state of a resource or component
3.1.50RFC
request for comment documents maintained by the IETF standards body containing standards in various stages of completion SIST EN 62676-2-1:2014

62676-2-1 © IEC:2013 – 13 – Note 1 to entry: This note applies to the French language only.
3.1.51RTCP packet Real-Time Transport Control Protocol (RTCP) control packet that consists of a fixed header part similar to that of RTP data packets and structured elements that vary depending upon the RTCP packet type, as described in RFC 3550
3.1.52RTP payload data transported in a packet by using Real-Time Transport Protocol (RTP), as described in RFC 3550
3.1.53RTP session association among a set of participants who are communicating by using the Real-Time Transport Protocol (RTP), maintaining a full, separate space of Synchronization Source (SSRC) identifiers, transmitted to the same destination IP address and UDP port Note 1 to entry: Typically, there is a one-to-one mapping between RTP streams and RTP sessions,
but it is possible for multiple RTP streams to use the same RTP session (port multiplexing). The associated RTCP traffic is also part of that RTP session although the packets are sent to the next higher UDP port number.
3.1.54RTP stream video stream that is encapsulated in RTP Note 1 to entry: All of the RTP packets have the same SSRC and are transmitted on the same RTP session.
3.1.55RTSP session session typically consisting of a VT client creating one or more RTP Sessions (SETUP) with a VT server, starting the stream with PLAY or RECORD, and closing the RTSP Session
3.1.56secure hash algorithm
SHA1
algorithm which generates out of input data like a message of less than 264 bits in length a 160-bit hash code or fingerprint designed in a way that it hardly possible to find a matching text string
service abstract resource that represents capabilities to perform tasks
3.1.57streaming process of sending video over a network to allow instant operation as the video is received, rather than requiring the entire file to be downloaded prior to operation
3.1.58transmission control protocol
TCP connection-oriented transport-layer protocol establishing a connection between host and recipient, guaranteeing delivery and reliability through retransmission
3.1.59TTL
time-to-live specified length of time that information e.g. DNS is stored in a cache and after that the information is deleted, e.g. entry from the DNS name server’s cache SIST EN 62676-2-1:2014

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3.1.60user datagram protocol
UDP connectionless transport layer protocol used to send messages as part of the IP suite of protocols with low overhead, not using Acknowledging (ACK) or error-checking (CRC), e.g. SNMP messages, not guaranteeing the delivery of a data packet with the advantage of using fewer network resources than TCP, making it more suitable for transporting streams of data or large amount of status messages
3.1.61universal resource identifier
URI a compact sequence of characters that identifies an abstract or physical resource on a server in a network
3.1.62video frame single image shown as part of a sequence of images in a video stream
3.1.63video management system
VMS system managing, accessing and controlling
the video transmission devices in real time in the video surveillance environment
3.1.64video surveillance system network
VSS network video surveillance system based on an IP video network used within a protected site
3.1.65video transmission device
VTD video device with at least one IP network interface handling video and typically coding or decoding video EXAMPLES: Encoders, decoders, NVR systems, video management systems.
3.1.66video transmission client
VT client video network device acting as client or receiver requesting video streams, status messages, etc. from a connected VTD server for the purpose of video recording, display, etc.
EXAMPLE: A VTD client can be a video management system workstation or a video decoder.
3.1.67video transmission server
VT server video network device acting as server or sender, encoding and sending video to a connected VTD Client, providing video streams, video status information, etc.
EXAMPLE: A VTD Server can be an IP network camera or a video encoder
3.1.68web service software entity that responds to SOAP messages capable of being defined, located via the Internet protocol, and interacting with other software applications, identified by a Uniform Resource Identity SIST EN 62676-2-1:2014

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3.1.69web service definition language
WSDL XML-based standard for specifying message-based distributed services containing either document- or procedure-oriented information
3.1.70XML schema a document that describes, in a formal way, the syntax elements and parameters of a web language, designed by W3C to replace DTD
3.1.71zeroconf
zero configuration networking a set of techniques that automatically create a usable IP network without configuration or special servers.
Note 1 to entry: In this standard only the service discovery is referred to. 3.2 Abbreviations API
Application Program Interface DA Device Architecture DCP Device Control Protocol DHCP
Dynamic Host Configuration Protocol DNS
Domain Name System DTD Document Type Definition DVR Digital Video Recorder HTML Hyper Text Mark-up Language HTTP
Hypertext Transfer Protocol IETF
Internet Engineering Task Force IP Internet Protocol IPsec
IP Security ISO
International Standards Organization IT Information Technology MPEG
Moving Pictures Experts Group NAT Network Address Translation NPT Normal Play Time NTP Network Time Protocol NVR
Network video recorder OASIS Organization for the Advancement of Structured Information Standards OSI Open Systems Interconnect PTZ Pan / Tilt / Zoom QoS
Quality of Service REST Representational State Transfer RFC (Request for comment) IETF Standards Draft RTCP Real Time Control Protocol RTP Real-time Transport Protocol
RTSP
Real Time Streaming Protocol SIST EN 62676-2-1:2014

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Session Description Protocol SMPTE Society for Motion Picture and Television Engineers SOAP
Simple Object Access Protocol SRTP
Secure Real-time Transport Protocol SSL
Secure Sockets Layer SSRC Synchronization source TCP
Transmission Control Protocol TCP/IP Transmission Control Protocol / Internet Protocol TLS Transport Layer Security TTL Time-to-live UDP User Datagram Protocol UPnP
Universal Plug and Play URI Uniform Resource Identifier URL
Uniform Resource Locator UTC
Universal Time Coordinated UTF
Unicode Transformation Format UTF-8
8-bit Unicode Transformation Format VMS Video management system VSS Video Security Systems VT
Video Transmission VTD
Video Transmission device W3C World Wide Web Consortium WS
Web Service
WSDL
Web Services Description Language XML
eXtensible Markup Language Zeroconf
Zero Configuration Networking 4 Video transmission network architecture
4.1 General To achieve interoperability between connected digital video devices in the VSS network, a common set of building blocks based on existing standards is needed as a basis to develop the video transmission standards. The present transmission network architecture is informative Figure 1 illustrates these functional components within the networking architecture of the video transmission standards. The video transmission standards define usage of these functional components to ensure interoperability among device classes defined in Clause 6. A brief overview of each functional component follows in the subsequent subclauses. SIST EN 62676-2-1:2014

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Figure 1 – Overview IP Video standard protocol Figure 2 shows the specific functional components and technology ingredients that are covered in the video transmission standards.
Figure 2 – Functional protocol layers 4.2 Networking and connectivity
General 4.2.1The IP video protocol suite is the foundation for networking and connectivity for VT devices in the digital VSS network. IP also provides the underlying network communications for applications in security. Based on industry-standard specifications from the IETF, IP is implemented and supported in a wide range of devices. IP has the following advantages for use by VT devices: • IP has demonstrated that it allows applications to run over different network topologies transparently; • IP allows connecting every device to a VSS network or even to a security network; • IP connectivity solutions are widely used and are cost-effective. The most common ones are Ethernet (802.3i and 802.3u) and wireless technologies (802.11n, 802.11b, and 802.11g) for devices in the VSS security networking environment.
RTSP/RTP HTTP 1.1 Discovery TCP, UDP Ethernet, Wi-Fi Video Transport Device Description Capabilities Configuration Service Discovery Network protocol stack Physical layer connectivity IEC
2729/13 IEC
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– 18 – 62676-2-1 © IEC:2013 The following subclause specifies the detailed protocols to enable interoperability between VT devices in the digital VSS network. In addition, the VSS network environment requires supporting network infrastructure, such as access points, bridges, gateways, routers, and switches. These non-normative devices are referred to in this standard as network infrastructure devices. IEC 62676-1-2 provides performance criteria for video network streaming and infrastructure devices to facilitate a good user experience and interoperability for video transmission devices.
Network streaming performance: quality of service 4.2.2Video surveillance applications on IP networks benefit from high network performance and a good quality of service (QoS) to optimize the way shared network resources are allocated among different surveillance applications, functions and devices. All applications running on different video transmission devices have according to the nature of IP networks an equal opportunity to transmit data frames. Video surveillance is according to IEC 62676-1-2 sensitive to delay, latency variations and bandwidth reductions. By stream limitations or prioritized streaming IP video devices define how the video packets access network resources. In contrast to broadcasting applications with an unknown number of clients, IP video in security does not define any QoS protocol today. The QoS in a surveillance network is guaranteed by the proper setup and configuration at design time for a certain number of operators or receivers and by using the capabilities of a video management system (VMS) taking care of all video streaming and requests of the single video transmission devices. Requirements on the quality and performance on streaming are listed in IEC 62676-1-2. 4.3 Device discovery and description Device discovery and description enables a device on the VSS network to discover the presence and capabilities of the device itself and other devices on the network and collaborate with these devices in a uniform and consistent manner. ZeroConf and WS-Discovery address all of these needs and simplify device networking in the VSS network. For this reason device discovery and description is part of the IP solution for VT devices. Clause 10 specifies the detailed protocols to enable interoperability between VT devices in the digital VSS network. IEC 62676-1-2 specifies that under secure conditions devices cannot be automatically discovered; network security is then assured and addressed in IEC 62676-1-2. 4.4 Video media types and payload formats Video formats describe how content is encoded and formatted for transport and final rendering on the VSS network. The video formats listed in IEC 62676-1-2 are intended to achieve a baseline for network interoperability while encouraging continued innovation in video codec technology. 4.5 Video transport Video transport defines how content travels across the VSS network. VT devices that offer or receive video streams across the VSS network shall support the streaming protocols. Clause 8 specifies the detailed protocols to enable interoperability between VT devices in the digital VSS network. 4.6 Eventing and health check In security providing video streams only is not sufficient. In Clause 11 the need to monitor the health status of video transmission devices and notify events is specified.
62676-2-1 © IEC:2013 – 19 – 5 The building block of existing standards
To achieve interoperability between connected digital video devices in the VSS network, a common set of building blocks based on existing standards is needed as a basis to develop the video transmission standards as shown in the Figure 3 below. The building block of existing standards given here are informative.
Figure 3 – Building block of existing standards 6 VSS device model 6.1 Overview A VTD example network is given in the Figure 4 below. IEC
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Figure 4 – VTD example network The video transmission standards address the requirements of devices with differing application characteristics, such as
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